Optional Science Book Class 10

Types of organ transplantation

On the basis of the genetic relationship between the !lsogratt !
donor and recipient, transplantation is classified
into four types: autograft, isograft, allograft -(8«1ticalTwin$ I
(homograft) and xenograft (heterograft).

1. Autograft: In autograft, the donor and fig: Types of organ transplantation
recipient is the same individual. In this
transplantation, one’s own tissue from a
part of the body is transplanted to another
part of the body. A common example of
this transplantation is skin graft for plastic
surgery. The success rate is high for this
type of transplantation.

2. Isograft: In isograft, the donor and recipient are genetically identical individuals, i.e.
identical twins. Example: kidney transplantation

3. Allograft (Homograft): In allograft, the donor and recipient are genetically different
but are of the same species. Example: Skin transplantation and blood transplantation
from others.

4. Xenograft or heterograft: In xenograft, the donor and recipient are of different species,
i.e. from a monkey to a human or from a pig to a human. This is a special case of
transplantation carried for research and experiment. Examples: transplantation of
baboon livers into humans.

Advantage of organ transplantation
1. It can be carried out to save life of a person dying of organ failure.
2. It helps in replacing a non-functional, damaged or lost body part with functional ones.

Disadvantages of organ transplantation

1. The main disadvantage is the rejection of the transplanted organ by the patient’s body
due to production of antibodies by the patient’s immune system against the transplanted
organ. Patients may die due to allergies or reaction from the new transplanted organ.

3. Organ transplantation is very expensive. It may not be affordable for the real people in
need.

Prevention of graft rejection

Sometimes, the body does not accept the transplanted organ. The immune system recognizes
the donor organ as a foreign organ and attacks it, resulting in transplant failure. In such a case,
there is a need to remove the organ immediately from the recipient, which is called rejection.
The graft rejection can be prevented by the following measures:
1. Selection of organs from a genetically similar member.
2. Suppressing the immune system by radiation.

3. Performing tissue typing and blood grouping test.

4. Use of immune-suppressant drugs.

5. Use of monoclonal antibodies.

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Memory Plus

Many organs and tissues are donated by individuals at the time of their death. Others are
donated by living donors. Generally, donated organs are matched with individuals on an
organ-waiting list. Matching is based on a variety of factors, including blood and tissue
type, medical need, length of time on the waiting list and weight of donor and recipient.

High blood pressure

Our heart pumps blood around the body constantly every second of our lives. The pumping
of blood creates pressure, and we call that blood pressure. Blood pressure is the pressure
exerted on the walls of the arteries as blood flows through them. Blood pressure is of two
types: systolic blood pressure and diastolic pressure. Systolic blood pressure is the pressure
in the arteries as the ventricles of the heart contract. Diastolic blood pressure is the pressure
in the arteries as the ventricles of the heart relax. Our normal blood pressure is below120/ 80
and above 100/60. Here, the numerator value indicates the systolic blood pressure and the
denominator indicates diastolic blood pressure. Anyone whose blood pressure is more than
140/ 90mmHg for a sustained period of time is said to have high blood pressure. High blood
pressure is also termed as hypertension.

Memory Plus

Sphygmomanometer measures blood pressure. In order to measure blood pressure there
is use of Stethoscope along with Sphygmomanometer.

The arterial blood pressure is always written in systolic pressure by diastolic pressure in
mm of Hg form (e.g. 120/80 mmHg).

Symptoms of high blood pressure
Most of the people with high blood pressure will not experience any symptoms until it reaches
about 180/110 mmHg. The most common symptoms of high blood pressure are:
1. Headache lasting for several days
2. Nausea and dizziness
3. Vomiting
4. Blurred or double vision
5. Nose bleeding (epistaxis)
6. Sensation of irregular or forceful beating of the heart (palpitation)
7. Breathlessness or shortness of breath (dyspnea)
Causes of high blood pressure
There is no identifiable cause of high blood pressure, but there are some risk factors that may
cause high blood pressure.
1. Age - everyone is at a greater risk of high blood pressure as they get older. Prevalence of

hypertension is higher in people above 60 years of age.

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2. Family history: if we have close members with hypertension in the family, there are high
chances of developing hypertension.

3. Ethnic background (race): Research has indicated that people with African or south Asian
ancestry have a higher risk of developing hypertension compared to American people.

4. Body size: Being both overweight and obese is a key risk factor for hypertension.

5. Gender: In general, men are more prone to hypertension than females. But generally, men
are prone to hypertension at a younger age and women have a higher rate of hypertension
in older age.

6. Lifestyle of an individual: lack of exercise, greater intake of dietary salt, high fat diet and
excessive intake of alcohol and smoking contribute to increased risk of hypertension.

7. Mental stress: various studies have said that people with mental stress over a long period
of time is at higher risk of hypertension.

Effects of high blood pressure

If high blood pressure is not treated or controlled, the excessive pressure on the artery walls
can lead to damage of the blood vessels as well as vital organs. Some of the effects of high
blood pressure are:

1. Stroke: blood flow to the brain is impaired by blockage and rupture of an artery to the
brain, and the brain cells die, causing a stroke. It may lead to death.

2. Heart attack: due to the loss of blood supply, the heart muscle dies.

3. Heart failure: pumping blood with high Bleeding withi.n the brain
pressure into the blood vessels, the heart muscle (hemorrhagic stroke) , /
thickens and fails to work.
Loss of sight from :-..
4. Blood clot: some blood converts into solid state narrowing, closure.
due to high blood pressure and causes serious or bleeding of
complications.
small vessels

in the retina

5. Kidney disease: high blood pressure damages
the small blood vessels in the kidneys, due to
this they cannot function properly.

6. Eye disease (hypertensive retinopathy): If high /

blood pressure is not treated in time, the blood fig: Effects of high blood pressure

vessels in the eyes may tear or get thickened,
which can lead to vision loss.

Control measures of high blood pressure
1. Lowering the intake of dietary salt: modest blood pressure reductions can be achieved by

lowering the amount of salt intake by people with hypertension.

2. Regular physical exercise: people suffering from hypertension should engage in at least
30 minutes of moderate physical exercise, such as walking, jogging, cycling or swimming.

3. Reducing weight and maintaining it: As we know, hypertension is closely related to
body weight, so it is important to maintain normal weight. Reduction in weight leads to
fall in blood pressure.

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4. Increasing the consumption of vegetables and fruits: people suffering from hypertension
or at risk of hypertension should eat whole grain, high fibre foods, more vegetables and
fruits to minimize the effects of high blood pressure.

5. Moderation of alcohol consumption: excessive drinking is associated to raise the blood
pressure with a high risk of stroke. People with hypertension or at risk of hypertension
should lower the alcohol consumptions.

6. Decreasing the consumptions of dietary fat: People with hypertension or at risk of
hypertension should minimize the intake of saturated and total fat.

7. Stress reduction: Avoiding sources of stress and developing healthy lifestyles can manage
stress that can help to control blood pressure.

8. Quitting smoking: Smoking also raises blood pressure and has adverse effect on health.
Therefore, People with hypertension or at risk of hypertension are highly recommended
to give up smoking.

Fact with reason

Patients with high blood pressure should not eat food with high amounts of salt, why?
Patients with high blood pressure should not eat food with high amounts of salt because
too much salt in our diet makes our body hold on to more water, which raises your blood
pressure and puts strain on our heart and kidneys.

Activity

Measure the blood pressure of all the students present in your classroom Fill the data in a
table. Make a comparative study of blood pressure on the basis of gender.

High cholesterol

Cholesterol is an oil based substance (lipid) that does not mix with blood and distributed
throughout the body. It is carried to different parts of the body through blood by lipoproteins.
Cholesterol is both beneficial and harmful to us. At normal level, it is an essential substance
for the body. But, if its concentration in the blood gets too high, it is dangerous for the heart
and health. It is found in every cell of the body and has important natural functions. It helps in
digesting food, producing hormones , generating vitamin D. It is manufactured by our body
and also taken from food.

Fact with reason

High cholesterol can cause heart attacks and strokes. Give reason.

If the cholesterol level in our blood gets too high, it starts to deposite in the walls of our arteries.
This is called hardening of the arteries (artherosclerosis). This can narrow the arteries and makes
it harder for blood to flow through them, leading to dangerous blood clots and inflammation
that can cause heart attacks and strokes.

0354 Optional Science - 10 BIOLOGY

Types of Lipoproteins that carry Cholesterol
There are two types of lipoproteins that carry cholesterol:
1. Low density lipoprotein (LDL): It transports cholesterol around the body where it is

needed. The cholesterol carried by this type of lipoprotein is termed as bad cholesterol. If
the level of cholesterol is too much, it may get deposited in the arteries and raise the risk
of heart attack and stroke.
2. High density lipoprotein (HDL): It carries away excess cholesterol from our cells and
tissues and returns it to our liver. This cholesterol is reused whenever needed by our
body. The cholesterol carried by this type of lipoprotein is termed as 'good cholesterol'.

Memory Plus

Increase in the level of LDL leads to deposition of cholesterol in the arteries, whereas
HDL carries cholesterol to the liver for removal from the body.

Fact with reason

Low density lipoprotein (LDL) cholesterol is known as 'bad cholesterol', why?

Low density lipoprotein (LDL) cholesterol is known as 'bad cholesterol' because having
high levels of LDL can lead to plaque buildup in our arteries and result in heart disease
and stroke.

High density lipoprotein (HDL) cholesterol is known as 'good cholesterol', why?

High density lipoprotein (HDL) cholesterol is known 'good cholesterol' as the lipoprotein
absorbs this cholesterol and carries it back to the liver, which flushes it from the body.

Causes of high cholesterol

1. The primary cause of high cholesterol is genetic. It starts to rise after the age of 20.
2. Being overweight or obese can also lead to higher blood LDL levels.
3. Other conditions like diabetes, liver or kidney disease, etc. also raise the level of cholesterol.
4. Pregnancy and underactive thyroid gland also increase the cholesterol level.
5. Some drugs like progestins, anabolic steroids and corticosteroids also increase LDL

cholesterol and decrease HDL cholesterol.

Effects

1. Deposition of cholesterol in the arteries narrows it. This condition is termed as
atherosclerosis. In this case, plaques form in arteries and cause restriction of blood flow.

2. High cholesterol is a major risk factor for coronary heart disease(CHD) like heart attacks
and stroke.

3. It causes pain and discomfort in the chest.
4. High cholesterol can create problem with blood flow to the legs, causing numbness.
5. High cholesterol can cause bile imbalance that leads to formation of gall stones.

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Control measures of high cholesterol
In order to manage high cholesterol levels to reduce the risk of coronary heart disease and
heart attacks, some changes in the lifestyles of a person are recommended.

1. Limiting intake of fat in the diet helps to manage the cholesterol level.

2. Eating vegetables, fruits and fiber-rich whole grains also helps to lower the risk of high
cholesterol.

3. Regular exercise also helps to maintain the cholesterol level.

4. Avoiding smoking

5. Achieving and maintaining a healthy weight.

Memory Plus

Having high cholesterol levels does not show any signs or symptoms. Unless routinely
screened through regular blood testing, high cholesterol levels will go unnoticed and
could present a silent threat of heart attack or stroke.

Uric acid

Uric acid is a waste product obtained during the breakdown of purines found in foods such
as liver, mushrooms, dried beans, etc. kidneys filter uric acid from blood and passes out of
the body in urine. A small amount passes out of the body in stool. However, if the kidney
fails to function at the appropriate level, or if uric acid intake is too high to be balanced by
kidney excretion then the level of uric acid in the blood increases. This condition is known as
hyperuricemia.

Normal uric acid levels are 2.4-6.0 mg/dL (female) and 3.4-7.0 mg/dL (male). The high
concentration of uric acid in the blood is converted into urate crystals. These urate crystals then
accumulate around the joints and soft tissues to cause inflammation and pain. This is known
as gout. Gout is the most common form of inflammatory arthritis, called gouty arthritis. It is
caused by the high uric acid level in blood. These crystals accumulate in the joints and bring
about a gout flare-ups. Gout is most commonly seen in men between the ages of 40 and 50.

Symptoms of Gout

Gout has painful and distinctive symptoms during flare-ups. The common symptoms of gout are:
1. There is intense joint pain. The pain is most severe in the first 12 to 24 hours.

2. Joint pains spread to more joints over a week.

3 Redness, tenderness and swelling of the joints

Effects of Hyperuricemia

Gout affects the ankles, heels and toes. The painful gout flare is concentrated in the joints.
Following are the effects of hyperuricemia:

1. Patient suffers a low fever of 99oF to 100ᵒF.

2. Patients suffering from gout experience swelling and pain in the ankles, knees, feet, wrist
or elbows.

2. Chronic gout reduces the function of the kidney. It may result in the formation of kidney
stones.

3. If gout is untreated, it can cause deposition of large lumps of urate crystal at joints and
results in permanent damage to the joints.

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Causes of gout

There are several factors that can make a person more susceptible to gout. Following are the
major causes of the high levels of uric acid that lead to gout:

1. Diet rich in purines: Purines are broken down by our body into uric acid. Foods that
contain high levels of purines include nuts, organ foods such as liver, kidney, etc.

2. High production of uric acid: This can happen in certain inherited genetic metabolic
disorders, leukaemia and during chemotherapy for cancer.

3. Less filtration of uric acid by the kidneys: This can be caused by kidney disease,
starvation and alcohol use. This also can occur in people taking medications.

4. Obesity or sudden weight gain: In case of the obese people, the body’s tissues break
down more purines. This can cause high uric acid level in blood.

Control measures of gout

1. Doing regular exercise.

2. Eating fresh fruits (e.g. cherries) and vegetables.

3. Avoiding high purine foods, such as dried beans and peas, mushrooms, organ meats
(liver and kidneys), asparagus, etc.

4. Consuming baking soda increases the alkalinity of the blood and lower the amount of
uric acid.

5. Patients are advised to drink more water.

6. Limiting alcohol intake, especially beer.

7. Maintain normal weight in case of obesity.

Fact with reason

Gout patients should avoid foods that are rich in purines, why?
Gout patients should avoid foods that are rich in purines like meat and fish as they increase
the amount of uric acid in a person’s blood, which can worsen the symptoms of gout. So,
gout patients should eat food with low protein content.

Antibiotic

Antibiotic is a combination of two Greek words: anti- against and bios- life. Therefore,
antibiotic is defined as a chemical substance produced by some microorganisms that have
the capacity to deactivate or kill other microorganisms. They are widely used in the field of
medicine to cure a number of diseases, especially bacterial infections. The antibiotics are very
reactive even in very low concentration.

Memory Plus

The first antibiotic was penicillin, which was discovered in 1929 by Alexander Fleming
from a mold culture.

Antibiotics are not effective against the viral diseases such as common cold or influenza.

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Types of antibiotics

On the basis of the action of antibiotics towards the pathogens, antibiotics are of two types:

1. Bactericidal antibiotics: Bactericidal antibiotics kill bacteria directly. The suffix ‘cidal’
means kill. Example: Metronidazole, Cotrimoxazole, Fluoroquinolones, etc.

2. Bacteriostatic antibiotics: Bacteriostatic antibiotics do not kill bacteria but stop the
growth or replication of bacteria. The suffix ‘static’ means stable. Example: Tertacydines,
Trimethoprim, Macrolides, etc.

On the basis of the effects of antibiotics towards the pathogens, antibiotics are of two types:

1. Narrow-spectrum antibiotics: Narrow-spectrum antibiotics are active against a selected
group of bacteria. For example, penicillin G is very effective in killing gram-positive
bacteria, but not very effective against gram-negative bacteria. It is used for specific
infection, when the causative organism is known. Narrow-spectrum antibiotic will not
kill the normal microorganisms in the body. Examples are Azithromycin, Clarithromycin,
Clindamycin, Erythromycin, Vancomycin.

Memory Plus

It's good to treat patients with antibiotics that have a narrow spectrum of activity.
The all 'good' bacteria that normally live inside of us will not get killed off along with
the pathogen that caused the infection.

2. Broad-spectrum antibiotics: Broad-spectrum antibiotics are active against a wider range
of microorganisms, which include both Gram-positive and Gram negative bacteria. They
may be used to treat a variety of infectious diseases. But use of broad spectrum antibiotics
may give rise to drug resistance.

In the case of severe infections, as it takes time to identify the causative bacteria, broad
spectrum antibiotic is used so that there will be no delay in treatment. This occurs, for
example, in meningitis, where the patient can become so ill that he/she could die within
hours if broad-spectrum antibiotics are not given. Examples: Amoxicillin, Levofloxacin,
Streptomycin, Tetracycline, Chloramphenicol.

Advantages and disadvantages of antibiotics

Antibiotics are effective against infections caused by pathogenic microorganisms and many
other diseases. The advantages of antibiotic are as follows:

1. Some antibiotics have been developed to attack human cells for the treatment of cancer.

2. They are applied to control bacterial and fungal damage in fruits and grains.

3. Small amounts of antibiotics are sometimes used to stimulate animal’s growth.

4. They used as food preservatives in canned or packed foods.

Disadvantages of antibiotics

Overuse of antibiotics is a major concern worldwide. Overuse of antibiotics contributes to the
increase in bacterial infections. The disadvantages of antibiotics are as follows:

1. Due to overuse of antibiotics, bacteria are becoming resistant to antibacterial medications.

2. Antibiotics can have side effects, such as diarrhea, vomiting, nausea.

3. They kill healthy bacteria in the body that can be useful for metabolism.

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4. Sometimes antibiotics can lead to complications like yeast infections.
5. Some antibiotics may cause allergy.

Fact with reason

Antibiotics should not be overused, why?

Antibiotics should not be overused or used incorrectly because there is a risk of bacteria
becoming resistant to antibiotics. The antibiotics becomes less effective against such
bacteria and be a problem in curing infections.

Blood Grouping Group A Group B Group AB GroupO

Although blood is made up of the same basic Red blood .),,,\(/.-
components, not all blood is alike. According cell 1ype /{";:--
to the ABO system of blood grouping, there are
four main types of blood groups- A, B, AB and Antibodies -n--,,,,)(j... Anli-A ),,)(.,i_ _),,,\!/.,
O. Our blood group is determined by the genes in Plasma
we inherit from our parents. A blood group is a Anti-B f _I!"'- /{";:--
classification of blood based on the presence or \I
absence of antigens on the surface of red blood B antigen
cells (RBCs) and antibodies in blood plasma. None Anti-A and Anli-B

Antigens in 'A antigen ,t None
Red Blood
A and B
Cell anligens

1. Blood group A has A antigens in the red blood cells with anti- B antibodies in the plasma

2. Blood group B has B antigens in the red blood cells with anti- A antibodies in the plasma

3. Blood group O has no antigens in the red blood cells, but has both anti-A and anti- B
antibodies in the plasma

4. Blood group AB has both A and B antigens in the red blood cells, but no antibodies.

Blood group Antigens in red blood cell Antibodies in plasma
O none anti-A & anti-B
A A anti-B
B B anti-A
AB None
A and B

Fact with reason

Receiving blood from the wrong ABO group can be life threatening, why?

An ABO incompatibility reaction can occur if a person receives the wrong type of blood
during a blood transfusion. For example, if someone with group B blood is given group
A blood, their anti-A antibodies will attack the group A cells. This is why group A blood
must never be given to someone who has group B blood and vice versa. As group O red
blood cells don't have any A or B antigens, it can safely be given to any other group.

The Rh Factor (Rhesus factor)

Red blood cells have another antigen other than antigen A and antigen B. Rh factor is the
protein known as RhD antigen that is present on the surface of RBC. If it is present in our
blood, our blood group is RhD positive. If it's absent, our blood group is RhD negative. This
means there are eight blood groups according to the Rh system:

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ABO blood group system Rh blood group system

O RhD positive RhD negative
A
B O+ O-
AB
A+ A-

B+ B-

AB+ AB-

Memory Plus

The most well-known and medically important blood types are in the ABO group. They
were discovered in 1900 and 1901 at the University of Vienna by Karl Landsteiner in the
process of trying to learn why blood transfusion sometimes causes death and at other
times saves a patient. In 1930, he belatedly received the Nobel Prize for his discovery of
blood types.

Rh-Factor was first isolated from RBC’s of Rhesus Monkey by Karl Landsteiner and
Wiener in 1940.

Activity

Blood Group Test
Materials Required:

1. Monoclonal antibodies (Anti-A, B and D) 2. Blood lancet

3. Alcohol swabs 4. Tooth picks

5. Sterile cotton balls 6. Clean glass slide

Procedure

1. Rub the finger tip of a person with the help of the alcohol swab. Alcohol is used as a
disinfectant.

2. Open the lancet cover, put pressure on the tip of the finger from where blood will be
sampled. Then, prick the finger tip with the opened Lancet.

3. As blood starts oozing out, make 1 drop fall on three places of the glass slide.

4. Place a cotton ball at the site where it was pricked. Using the thumb, put pressure on
the area to stop the blood flow.

5. Take the Anti-A (blue) bottle, place a drop of it on the 1st spot.

6. Take the Anti-B (yellow) bottle; place a drop on the 2nd spot.

7. Take the Anti-D (colorless) bottle; place a drop on the 3rd spot.
8. Take a tooth pick and mix the content in each spot. Use a new tooth pick for each spot.
9. After mixing, wait for a while to observe agglutination (clumpings).
Observation and Result

If we see clumping in first spot after putting anti-A, then its blood group is A. Similarly,
if we see clumping in blood labeled B after putting anti-B, then its blood group is
B, and if we see clumping in both A and B, then the blood group is AB. Similarly,
agglutination of sample D indicates the Rh+.

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Answer writing skill

1. What does graft mean?
Graft means the tissue or organ that is transplanted. For example, kidney taken from a
donor person is a graft.

2. What is isograft?

Isograft is the type of transplantation between the donor and recipient who are
genetically identical, i.e. identical twins. Example: kidney transplantation

3. Define high blood pressure.

High blood pressure can be defined as blood pressure that is more than 140/ 90mmHg
for a sustained period of time.

4. Define hyperuricemia.

Hyperuricemia is defined as the condition of high uric acid level in the body. This
condition occurs in the body either when the kidneys excrete too little uric acid or when
the body produces too much uric acid.

5. The success rate of organ transplantation is very low. Give reasons.

Organ transplantation from a different individual may result in the rejection of the
transplanted organ due to the production of antibodies against the transplanted organ.
This may cause reaction in the blood. Therefore, the success rate of organ transplantation
is very low.

6. Write the difference between systolic and diastolic pressure.

The difference between systolic and diastolic pressure is as follows:

Systolic pressure Diastolic pressure

1. Systolic blood pressure is the pressure 1. Diastolic pressure is the pressure in

in the arteries as the heart contracts. the arteries as the heart relaxes.

2. It is written usually as the numerator. 2. It is written usually as the
denominator.

7. Write short notes on the ABO system of blood grouping.

According to the ABO system of blood grouping, there are four main types of blood
groups- A, B, AB and O. A blood group is classified based on the presence and absence
of antibodies and antigens on the surface of the red blood cells (RBCs). The blood of
different persons is determined as A, B, AB and O on the following bases:

i. Blood group A: If a sample of blood clumps with anti-A serum, then it is Blood Group A.

ii. Blood group B: If a sample of blood clumps with anti-B serum, then it is Blood Group A.

iii. Blood group O: If a sample of blood does not clump with both anti-A and anti-B
serum, then it is Blood Group O

iv. Blood group AB: If a sample of blood clumps with both anti-A and anti-B serum,

then it is Blood Group AB.

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8. What are the causes of cholesterol?

The causes of cholesterol are as follows:

i. The primary cause of high cholesterol is genetic.
ii. Being overweight or obese can also lead to higher blood LDL levels.
iii. Other conditions like diabetes, liver or kidney disease, polycystic ovary syndrome

also raise the level of cholesterol.
iv. Pregnancy and underactive thyroid gland also increase the cholesterol level.
v. Some drugs like progestin, anabolic steroids and corticosteroids also increase the

LDL cholesterol and decrease HDL cholesterol.
9. What are the effects of gout?

Gout affects the ankles, heels and toes. The painful gout flare-up is concentrated in the
joints. Patients suffering from gout experience swelling and pain in the ankles, knees,
feet, wrist or elbows. If gout is untreated, it can cause permanent damage to the joints
and kidneys.

10. Explain in short about the types of antibodies on the basis of the effects of antibiotics
towards the pathogens.

An antibiotic is a chemical substance produced by some microorganisms that have
the capacity to deactivate or kill other microorganisms. On the basis of the effects of
antibiotics towards the pathogens, antibiotics are of two types:

a. Narrow-spectrum antibiotics: Narrow-spectrum antibiotics are antibiotics that
are active against a select group of bacteria. They are used for specific infection
when the causative organism is known. Example: Azithromycin, Clarithromycin,
Clindamycin, Erythromycin, Vancomycin.

b. Broad-spectrum antibiotics: Broad-spectrum antibiotics are antibiotics that are
active against a wider range of microorganisms, which include both gram positive
and gram negative. It may be used to treat a variety of infectious diseases. Example:
Amoxicillin, Levofloxacin, Streptomycin, Tetracycline, Chloramphenicol.

0362 Optional Science - 10 BIOLOGY

Exercise

Section "A"

1. What is an organ transplantation?

2. Give the names of the organs that can be transplanted.

3. Name the organs that are not possible to transplant yet.

4. What is autograft?

5. Give one example of each of the followings:

a. autograft b. isograft

c. allograft d. xenograft

6. What is heterograft?

7. Define blood pressure.

8. Name the instrument used to measure blood pressure.

9. What is cholesterol?

10. What is uric acid?

11. What is gout?

12. Define antibiotic.

13. What is Rh factor?

14. What do you mean by blood group?

15. What is artherosclerosis?

Section "B"

1. Write differences between xenograft and allograft.
2. What is the difference between isograft and allograft?
3. Write two differences between systolic blood pressure and diastolic blood pressure.
4. Write two differences between low density lipoprotein and high density lipoprotein.
5. What are the types of antibiotics?
6. Write the difference between bactericidal and bacteriostatic antibiotics.
7. Differentiate between narrow and broad-spectrum antibiotics.
8. Write in short about ABO blood group system.
9. Write a short notes on the Rh blood group system.

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Section "C"

1. State the advantages of organ transplantation.
2. What are the disadvantages of organ transplantation?
3. List the symptoms of high blood pressure.
4. What is the effect of blood pressure?
5. What are the symptoms of uric acid?
6. List the advantages of antibiotics.
7. What are the disadvantages of antibiotics?

Section "D"

1. Describe the procedure of organ transplantation.
2. What are the causes of high blood pressure? Mention some of the control measures of

high blood pressure.
3. What is cholesterol? What are the types of cholesterol?
4. What are the effects, causes and control measures of high cholesterol?
5. What are the causes and control measures of gout?
6. Describe the procedure of a blood group test in brief.
7. Explain about the types of antibiotics.

Multiple choice questions

1. The process of transplanting the organs is called

a) Surgery b) Keratoplasty c) Tissue culture d) Dialysis

2. The tissue or organ which gets transplanted is called a

a) Graft b) Sample c) Keratoplasty d) Donor

3. Our normal blood pressure is below

a) 120/ 80 b) 100/ 60 c) 120/ 90 d) 130/ 80

4. Antibiotics are mostly used to treat

a) Bacteria b) Fungi c) Virus d) Protozoa

5. If a sample of blood does not clump with both anti-A and anti-B serum, then it is

a) Blood Group A b) Blood Group B c) Blood Group AB d) Blood Group O

6. Rh factor is present on the surface of

a) RBCs b) WBCs c) Blood d) Plasma

Project Work

Conduct a survey in your neighborhood to compare the blood pressure rate in men and
women. Prepare a report and submit it to your teacher. Ask the blood group of your
friends in class. Prepare a report and submit it to your teacher.

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UNIT

19 THE EARTH

Inge Lehmann (1888–1993) was a Danish seismologist and geophysicist. Based on her

studies on seismology, in 1928 she earned the magister scientiarum degree in geodesy

and accepted a position as state geodesist and head of the department of seismology at the

Geodetical Institute of Denmark. In 1936, she discovered that the earth has a solid inner

core. Lehmann was also the longest-lived woman scientist. She lived to be over 104 years old,
and died in 1993. She received many honours for her outstanding scientific achievements.
She was awarded honourary doctorates from Columbia University in 1964 and from the
University of Copenhagen in 1968, as well as numerous honorific memberships.

Key terms and terminologies of the unit

1. Minerals: Minerals are naturally occurring non-renewable resources which have
constant chemical composition and stable physical properties.

2. Ores: The combined states of solid minerals from which metal can be extracted are
called ores.

3. Gemstones: A gemstone is a piece of mineral crystal which is used to make jewelry
or other ornaments in its cut and polished form.

4. Natural Gas: Natural gas is a naturally occurring mixture of hydrocarbon gas inside
the earth crust consisting primarily of methane.

5. Fossils: The preserved remains, impression or trace of living organisms which were
buried in the earth's crust million years ago are called fossils.

6. Shaligram: The ammonites found in the Kali Gandaki River of Himalayan region
are called Shaligram in Nepali language.

7. Radioisotope: Radioisotope is a form of an element with an unstable nucleus.
8. Radioactive decay: The process of nuclear disintegration is called radioactive decay.
9. Radiometric dating: The method of finding the age of a material by measuring

radioisotope and its daughter elements is called radiometric dating.
10. Half-life: The time taken to decay half of a sample of radioisotope is called half-life.

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Introduction

Earth is a rocky, terrestrial planet. It consists of land, air, water and life. The land contains
active surface with mountains, valleys, canyons, plains, etc. Our home planet is not a perfect
sphere. The north and south poles are slightly flat. The equator is an imaginary circle that
divides earth into two halves. The northern half is called the northern hemisphere and the
southern half is called the southern hemisphere. A major part of the lithosphere lies in the
northern hemisphere while the southern hemisphere is mostly made up of oceans. Nepal is
also in the northern hemisphere of the earth.
Nepal occupies only 0.1 percent of the earth's land surface. It has an area of 147,181 square
kilometers. Nepal is a land-locked mountainous country located at the central part of the
Himalayan belt and bordered to the north by China and to the south, east, and west by India.
About 17 percent of the land is plain and remaining 83% has hills and mountains. Nepal is rich
in different types of natural resources like water, minerals, forest and medical herbs. Various
types of metallic, non-metallic minerals and fossils are found here. In this unit, you will learn
about Nepal's geographic diversity and natural resource, identification of age of the rocks on
the basis of radioactive decay method, etc.

Geologic diversity of Nepal

Nepal is situated in the southern slopes of Himalayas. It has a wide range of geologic diversity
within very short distance. It is like a rectangle in shape with 885 km east-west length and an
average north-south width of 193 km. The landscape of Nepal ranges from 70m in the south
to the highest peak of 8848m in the north from sea level.

Terai Zone
Sub-Himalayan Zone
Lasser-Himalayan Zone
Higher Himalayan Zone
Tibetan Tethys Zone

.. . .....", 1$ .....

fig: Geological map of Nepal

Geologic structure of Nepal is very complex. The continuous geodynamic process in the
Himalayan region results in many thrusting, faulting, folding and metamorphic events.
Nepal can be divided into five morpho-geotectonic zones from south to north on the basis of
availability of mineral resources. They are: Terai Zone, Sub-Himalayan (Siwalik) Zone, Lesser
Himalayan Zone, Higher Himalayan Zone and Tibetan-Tethys Himalayan zone.

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Terai zone

The southernmost zone is called the Terai. To the north, this zone is separated by an active
thrust system called as the Main Frontal Thrust (MFT) with the Siwalik. The Terai zone is also
called Gangetic Plain. It spreads in 17 percent of the total land area of Nepal.

a. North to south extension, i.e. width: The width of the Terai zone varies from 10 to 50
km. It extends from the Indian border in the south to the Sub-Himalayan (Siwalik) zone
to the north.

b. East to west extension, i.e. length: The Terai zone is interrupted by Siwalik for 70 km at
Chitwan and 80 km at the Rapti Valley.

Rocks and Minerals: It has thick alluvial sediments. This zone is rich in boulder, gravel,
silt, and clay. There is high potential for petroleum and natural gas in the Terai zone of our
country.

Sub-Himalayan Zone (Churia/Siwalik foothills)

The Sub-Himalayan zone lies in between the
Terai and Lesser Himalayan zone.

Rocks and Minerals: The Siwalik region is fig: Geographical diversity in Nepal
the potential area for construction materials,
radioactive minerals, petroleum, natural gas
and minor amount of coal. The Siwalik zone
consists of irregularly laminated beds of fine
grained greenish sandstone, and siltstone with
mudstone.

Lesser Himalayan Zone (The Mahabharata range including mid hills)

The Lesser Himalayan zone lies in between the Sub-Himalayas and Higher Himalayas.

Rocks and Minerals: From east to west, the Lesser Himalayan zone of Nepal varies in rock
type, their age, structures, and igneous rock intrusion. In this zone, high grade metamorphic
rocks are found in the eastern part. This zone is rich in the following minerals:
a. Metallic minerals mainly iron, copper, lead, zinc, cobalt, nickel, tin, tungsten,

molybdenum, gold, uranium, rare metal, etc.
b. Industrial minerals like magnesite, phosphorite, limestone, dolomite, talc, clay, kaoline,

graphite, mica, silica sand and quartz.
c. Gemstones like tourmaline, aquamarine/beryl, garnet, kyanite and quartz crystals.
d. Fuel minerals like coal, lignite, methane, petroleum, natural gas, hot springs and

radioactive minerals.

Higher Himalayan Zone

The higher himalayan zone is rich in following rocks and minerals.
Rocks and Minerals: It consists of huge pile of strongly metamorphosed rocks. Some of the
areas in the Higher Himalaya are highly promising for precious and semiprecious stones like
ruby, sapphire, and emerald and metallic minerals like lead, zinc, uranium, gold, silver, etc.

Tibetan Tethys Zone

The Tibetan-Tethys zone lies in the northern part of our country. It is rich in following minerals

and rocks.

Geology and Astronomy 0Science - 10 367

Rocks and Minerals: It is rich in sedimentary rocks, such as shale, limestone, and sandstone.
It also consists of gypsum, brine water (salt) and natural gas. The fossiliferous rocks of this
zone are well-developed in Thak Khola (Mustang), Manang, and Dolpa areas of our country.
This region is 40 km wide.

Status of Mineral Resources in Nepal

Minerals are the non-renewable natural resources. They are formed by various geodynamic
processes. Minerals are naturally occurring non-renewable resources which have constant
chemical composition and stable physical properties.

In Nepal, the Department of Mines and Geology (DMG) and the UN-funded Mineral
Exploration Development Project (MEDP) explored minerals at different part of the country
from 1974 to 1980. Geological investigations and mineral exploration activities carried out
mainly by DMG, UNDP/DMG/MEDP projects, Geological Survey of India (GSI) and a few
private entrepreneurs were able to identify more than 66 minerals in Nepal. Some of the
important minerals are described below.

Metallic mineral

Metallic minerals are those minerals which have a metallic luster and are opaque. Metals are

extracted from their respective ores. Some of the least reactive metals like gold are available

in their native form. Other reactive metals are found in a combined state with other elements

like Oxygen, Sulphur, etc. Thus, the combined states of a metal from which the metal can be

extracted economically are called ores. Some of the important metals in different parts of our

country are given below.

Iron (Fe)

Iron is a widely used metal in the construction works as well as in machinery parts. The main
ores of iron like magnetite, haematite, limonite are reported from more than 85 localities in
Nepal. In Dhaubadi of Nawalparasi, a team of experts had located a huge deposit of iron ore
in 2016 AD. Local people claim that the ore used to be sent up to Palpa district during the rule
of Sen Kings. A governmental team with experts had visited the place and studied the
possibility of extracting iron from the huge deposit.

Other well-known iron ore deposits are Phulchoki fig: A team of expert located a fig: Iron ore
(Lalitpur), Thoshe (Ramechhap), LabdiKhola huge deposit of iron in Dhaubadi
(Tanahun), Jirbang (Chitwan), Dhuwakot of Nawalparasi in 2016 A.D.
(Parbat), Purchaundi/ Lamunigad (Bitadi),
Dahabagar, and Ekghar/ Khanigaon (Bajhang).
These ores are also known from different parts
of Baitadi, Bajhang, Jajarkot, Rolpa, Surkhet,
Myagdi, Baglung, Parbat, Chitwan, Ramechhap,
Okhaldhunga, Taplejung etc.

Memory Plus

Thoshe iron deposit was mined in small scale during Rana's regime for almost 100 years
till 2006 BS. But it was totally stopped after 2007BS.

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Copper (Cu)

Copper is another important metal which is mainly used in electrical industries to make
copper wires. It is also used to make pots, crafts, alloys, different sculptures, etc. It was mined
traditionally in Nepal long time ago. There is no running copper mine in Nepal at present. The
common copper ores found in Nepal are chalcopyrite, and few malachite, cuprite, chalcocite,
etc. These ores were found in more than 107 localities. The well-known copper ore deposits
are Gyazi (Gorkha), Okharbot (Myagdi), Wapsa (Solukhumbu), Kalitar (Makwanpur), Dhusa
(Dhadhing), Bamangaon (Dadeldhura), Khandeshori/ Marma (Darchula), Kurule (Udayapur),
Bhut Khola (Tanahun), Pandav Khani (Baglung), Baise Khani (Myagdi), Minamkot (Syangja),
Chhirling Khola (Bhojpur), Jantare Khani (Okhaldhunga).

Zinc (Zn) and Lead (Pb)

Zinc is used in galvanizing iron, dry battery, pigments, soldering, dyeing, glue making etc. It
is also used to manufacture various alloys like brass, bronze whereas the lead is used to make
lead sheets, pipes, alloys, pigments, dyeing, insecticide, medicine, etc.
The zinc and lead deposits are reported from more than 54 localities in different parts of
our country. The well-known deposits of zinc and lead ores are found in the Ganesh Himal
area (Rasuwa), Phakuwa (Sankhuwasabha), Labang- Khairang, Baraghare and Damar
(Makwanpur), Pangum (Solukhumbu), Salimar valley (Mugu/ Humla), Phulchoki (Lalitpur),
Sisha Khani and Kandebas (Baglung), Dhuwakot (Parbat), Bhaludanda (Dhadhing, Khola
Khani (Taplejung) etc.

Gold (Au)

Gold is a precious metal with worldwide market. It is widely used in making coins, ornaments,
jewelry, dental appliances, electroplating, metal coating and many other purposes. In Nepal,
alluvial/ placer gold are frequently wined by local dwellers (Botes) from the river gravel/
sediments deposited by the rivers like the Mahakali, Chamliya, Jamari Gad, Seti, Karnali, Bheri,
Rapti, Lungri Khola and Phagum Khola (Rolpa), the Kaligandaki, Myagdi Khola, Modi, Madi,
Marshyangdi, Trishuli, Budhi Gandaki, and Sunkoshi. There is no gold mine yet reported in
Nepal although local people extract small scale of gold from above mentioned rivers.

Silver (Ag)

Silver is mainly used to make ornaments, jewelry, coins, handicrafts, utensils dental fillings,
etc. It is generally associated with zinc-lead ores. In Nepal, small amount of silver is reported in
the zinc-lead ore of Ganesh Himal (Rasuwa), Barghare (Makwanpur) and polymetalsulphide
of Biring Khola (Ilam), Netadarling (Arghakhanchi) and Samarbhamar (Gulmi). Silver ore has
not yet been reported in Nepal; however, it is present in association with zinc-lead ores and
gold.

Nonmetallic Minerals

Nepal is rich in nonmetallic minerals. A numbers of nonmetallic minerals like magnesite,
phosphorite, talc, limestone, dolomite, quartz, mica, clay, silica sand, gemstones, decorative
and dimension stones are known to exist in different parts of Nepal. Some of the explored
nonmetallic minerals are briefly described below:

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Limestone

Limestone is the main raw material to manufacture cement. According to a report of the
Department of Mine and Geology (DMG), a number of large to small size limestone deposits
are in Nepal. Preliminary studies indicate that there is a possibility to find more than 2.5
billion tons of cement grade limestone deposits in the Lesser Himalaya zone. Some of the main
cement grade limestone deposits are found in Sinduhuli and Galtar (Udayapur); Bhainse,
Okhare and Nibuwatar (Makwanpur); Jogimara and Beldada (Dhadhing); Chovar,
Bhattedanda (Lalitpur); Balthali and Nandu (Kavre); Kakaru Khola (Sindhuli); Kajeri (Salyan);
Nigale (Dhankuta); Chaukune and Lakharpata (Surkhet); Gandari (Dang); Narapani and
Supa Khola (Arghakhanchi); Diyarigad (Baitadi) and a few other places in Khotang, Syangja,
Palpa, Pyuthan, Sallyan, Rolpa, Rukum, Bajhang, and Darchula districts.

Memory Plus

Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in
the form of the mineral calcite.

Dolomite

Dolomite occurs as crystals as well as in large sedimentary rock beds. It is used in paints, soap,
detergent and agriculture purpose. In many cases dolomite and limestone occur together.
From geological mapping it is known that there is a probability of occurrence of over 5 billion
tons of dolomite in different localities of Nepal, including Dhankuta, Khotang, Udayapur,
Sindhuli, Dolakha, Kavre, Kathmandu, Makwanpur, Dhadhing, Syangja, Palpa, Baglung,
Gulmi, Arghakhanchi, Dang, Pyuthan, Sallyan, Rolpa, Rukum, Jajarkot, Surkhet, Dailekh,
Jumla, Achham, Doti, Bajhang, Bajura, Baitadi and Darchula districts in the Lesser Himalayan
and in some parts of Higher Himalayan region.

Memory Plus

Dolomite is a type of compact limestone composed of calcium magnesium carbonate
(CaMg(CO3)2).

Phosphorite [Ca₃(PO₄)₂]

Phosphorite is one of the main raw materials to manufacture chemical fertilizers like fused
magnesium phosphate, triple super phosphate etc. Phosphorite is found in Dhik Gad, Junkuna,
Morgaon, Sanagaon and Dhaubisaune areas in Baitadi, Tarugad, Juilgad area as in Bajhang
and further east to Bajura, Sewar Khola (Dang), and Mari Khola (Pyuthan).
Magnesite

Magnesite is a source of magnesium. Magnesite is used to produce synthetic rubber, chemical
fertilizers, etc. It is also used to manufacture high temperature refractory bricks that can be
used for lining in the furnaces, steel industries and crucibles in chemical industries. Preliminary
studies have shown that 180 million tons of magnesite deposit is in Kharidhunga, Dolakha.
It is one of the biggest and best quality magnesite in south Asia. About 20 million tons of
medium to low-grade magnesite deposit is in Kampughat in Udayapur; and a few small size
magnesite occurrences are found in Palpa, Baitadi and Dolakha.

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Memory Plus

~ - - - 1Magnesite is a mineral with the chemical formula MgCO3 (magnesium carbonate).

Talc [H₂Mg₃(SiO₃)₄] or Mg₃Si₄O10(OH)₂

Talcum powder is an important ingredient in many baby powders, foot powders, first aid
powders, and a variety of cosmetics. It is also used in ceramics, paint, paper, roofing materials,
plastics, rubber, insecticides, and as dry fire extinguisher powder. It is found in Lalitpur,
Dolakha, Sindhupalchok, Dhadhing, Chitwan, Tanahun, Kaski, Syangja, Surkhet, Bajhang,
Bajura, Baitadi and Darchula districts.

Red Clay

Red clay is used to manufacture construction materials like bricks, roofing tiles, flooring tiles,
etc. It is also used to make earthen pots and in pigments for painting. Red clay from Panchkhal
(Kavre), Lamosure (Hetaunda), Trijuga/ Beltar (Udayapur), Chidika (Arghakhanchi) and
Guttu (Surkhet) are used in cement factory. Such red clay deposits are also known from
different parts of Nuwakot, Dhadhing, Makwanpur, Nawalparasi, Udayapur, Palpa and
Surkhet districts. Clay from Thimi/ Bhaktpur is used in small-scale pottery industries. A huge
amount of silty clay deposit in different parts of the Kathmandu Valley and other parts of our
country is used to manufacture bricks. In villages, it is also used in house wall painting.

Memory Plus

liiii~ - - -Red clay is a highly weathered clay deposit mineral which contains mostly hydrated
~ - - - 1silicates of aluminum and iron oxides.

Ceramic clay or Kaolin
Clay is a natural material that is obtained from the ground but ceramics are various materials,
including clay, which hardens when heated. Kaolin is mainly used in ceramics. It is also used
in medicine, paper, cosmetics, etc. Irregularly distributed kaolin are known from Daman
(Makwanpur), Panchmane (Kathmandu), Dalchhap and few other places.

1~~ - - -MemoryPlus
Ceramic clay or Kaolin is a type of soft white clay. The primary constituent in kaolin is a
hydrated aluminium silicate.

F-~~ ====================IKnowtheReason
Kaolin is also called China clay, why?

Kaolin is named after the Kao-ling mountain in China where it was first mined, for many
years before it was discovered in Europe in 1745. It is a source of white chinaware. So
Kaolin is also called China clay.

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Graphite

Graphite is mainly used in lead pencils, crucibles, paints, lubricants etc. It is one of the
significant minerals in metamorphic terrain in Lesser Himalayan region. It is reported from
different localities like Ilam, Dhankuta, Sankhusabha, Nuwakot, Sindhupalchok and
Dadeldhura.

Memory Plus

Graphite is a naturally occurring form of crystalline carbon. It is a native element mineral
found in metamorphic and igneous rocks.

Brine/Salt

Brine is a high-concentration solution of salt in water. It may refer to salt solutions ranging
from about 3.5% up to about 26% which is in a typical saturated solution. In Nepal, brine
water is available in the Narsing Khola (Mustang), Chhiding Khola and Chharkabhot (Dolpa).
It is tapped and dried for common salt production. Brine water of these areas contains 1.5 to
3% NaCl. So far mineable deposit of brine is not found in our country.

Gemstones diamod sapphire ruby emerald

A gemstone is a piece of mineral crystal which is used garnet peridot aquamarine topaz
to make jewelry or other ornaments in its cut and
polished forms. Gemstones consist of hard crystalline amethyst opal citrine zircon
substances with unique chemical and physical
properties. Gemstones are popularly mentioned in fig: gemstones
the myths and legends of human cultures throughout
history. They are believed to have special powers.
Traditionally, gemstones are considered as precious
and semiprecious.

Precious Gemstones

Diamond, Ruby, Sapphire and Emerald are considered precious gemstones.

Rubies and Sapphire

Ruby and Sapphire are the two precious gemstones found in Nepal. They are gems of the
mineral which has chemical composition of aluminium oxide (Al2O3).
Generally small crystals of light red to red ruby and light to dark blue coloured sapphire are
known from Chumar, Ruyil, Shelghar, Pola, Shongla (Dhadhing) and Lari/ Ganesh Himal
area (Rasuwa). They are found in highly folded metamorphic rocks.

Semiprecious Gemstones

All gemstones other than precious gemstones are considered as semiprecious gemstones.
Semiprecious gemstones found in Nepal include tourmaline, aquamarine/ beryl, garnet,
kyanite, amethyst, citrine, smoky quartz (quartz crystals).

Tourmaline

Tourmaline is the earth's most colourful mineral and gem material. It is available in pink,
bright green, light orange sometimes with repeated colour banding, olive green with amber
coloured core. It is found in the Langtang Valley (Rasuwa), Naje (Manang), Daha (Jajarkot),
etc. Tourmaline crystals are cut and polished for gem.

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Beryl/ Aquamarine

The Beryl gems are named by their colour as emerald (green), aquamarine (greenish blue to
blue), etc. Aquamarine of Taplejung (Ikabu, Lodantar) area is highly expensive. Phakuwa
(Sankhuwasabha), Lekhpatan and Tikachaur in Jajarkot; Jagat, Panchmane, Kagtigaon in
Kathmandu, Baguwa, Tarkeghyang, Nibuwagaon in Sindhupalchok are the other known
localities for Beryl.

Garnets
Garnets are a group of silicate minerals with combinations of metals within it. Red is the most
common colour, although it exists in different colours, including green, purple, black and blue.
Garnetsare found in metamorphic rocks in higher Himalayan region. Deep red or purplish red
coloured almandine, hessonite and pyrope garnet are found mainly in Sankhuwasabha and
Taplejung districts.

Kyanite
Kyanite is a mineral found mainly in metamorphic rocks. In Nepal, Kyanites are reported from
different localities like Dolakha, Sankhuwasabha, Taplejung, Rasuwa, Dhadhing, Jajarkot and
Achham districts. Some small-scale kyanite mines are in operation in Daha and Suneri in
Jajarkot and Barah of Aachham districts. Kyanite crystals are cut for gems.

Dimension Stones/Decorative Stones

Dimension stone is a collective name used for various natural stones which are trimmed to
specific size or shape for structural or decorative purposes in construction or monumental
applications. For example, granite, marble, quartzite, slate, etc.

Marble
Marble is a metamorphic rock. It is used for bathroom floors, wall covering and many other
decorative purposes in the residential and commercial buildings. In Nepal, about 1.63 billion
tons of pink, gray, and white coloured marble deposit is in Godawari (Lalitpur). It is also
found in Anekot (Kavre); Chhatre Deurali (Dhadhing); Bhainse and Sukaura (Makwanpur).

Granites
Granite is an igneous rock. Polished granite is used in flooring tiles, stair trades, kitchen
countertops and many other decorative features. Rough cut granite is used in buildings,
bridges, paving monuments, etc. In Nepal, granite is known from different localities like
Makwanpur (Palung and Ipa), Sindhuli, and Udaypur in the Lesser Himalayan region.

Quartzite
Quartzite is a metamorphic rock formed from quartz rich sandstone. It is a hard rock and
resistant to weathering. It occurs naturally in various forms, colours, designs and textures.
So it can be used for decorating outdoor and walls of the house. It is abundantly known from
many districts like Taplejung, Ilam, Dhankuta, Ramechhap, Sindhupalchok, Makwanpur,
Dhadhing, Tanahun, Kaski, Syangja, Parbat, Baglung, Achham, Doti, Bajhang, Bajura,
Dadeldhura, Baitadi and Darchula.
Slate
Slate is a fine-grained, homogeneous metamorphic rock derived from shale type
sedimentary rock. It is particularly used as roofing material. Slate tiles are used for
flooring, in stairs and walkways. It is also used for blackboards and writing slates.

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It is extensively mined from many districts like Dhankuta, Sindhupalchok, Ramechhap,
Nuwakot, Sindhupalchok, Dhadhing, Tanahun, Baglung, Syangja, Palpa, Parbat, Jajarkot,
Achham, Doti, Dadeldhura, Baitadi, Bajhang and Bajura.

Fuel Minerals

The minerals that can be used as fuel are called fuel minerals. For example, coal, petroleum
and natural gas. They are stripped from the earth. The lesser Himalayan region in Nepal
consists of coal, lignite, methane gas, petroleum, and natural gas.

Fossils found in Nepal

Volcanic activity and earthquakes on the earth alter the landscape in a dramatic way. Living
organisms get trapped inside the earth crust during changes on the earth's surface. A fossil
is a evidence of a once-living organism. The preserved remains, impression or trace of living
organisms which were buried in the earth's crust million years ago are called fossils. Fossils
can be the preserved entire body of the organism or just part of the body like bones, shells,
feathers, leaves etc. in sedimentary rocks. The fossil findings of plants and animals from Nepal
are supporting evidences in context of the geologic history of the Himalayas.

Cephalopod Fossils/ Ammonites (Shaligram)

A cephalopod is any member of the

molluscan class like squid, octopus,

etc. The extinct cephalopod molluscs

with a flat-coiled spiral shell are called

ammonoids. Ammonites are the fig: Shaligram
ammonoid fossils. The term ammonite is

derived from a term ammonis cornua which means the horn of Ammon; an Egyptian god who

wore curled horns on his head. They are among the most abundant fossils found in different

ports of the earth.

In Nepal, ammonites are found in the Himalayan region, Mustang. The ammonites found
in the Kali Gandaki River of Himalayan region are called Shaligram in Nepali language.
Shaligrams are black fossils. According to geologists, saligrams are 140 to 165 million years
old and found in two colors, black and white It is worshiped as a symbol of God Vishnu in
the homes of Vaisnava sect of the Hindus. The spiral shells in ammonites are the fossils of
ammonids. According to geologists, Shaligrams are 140 MY-165 MY old.

Memory Plus

Shaligram in the river look like black balls. Due to its specific colour the river was named
Kali Gandaki.

Brachiopod and Gastropod Fossils

The Siwalik zone is also rich in fossils. Fossils of plants, pisces, reptiles and mammals have
been reported from the Siwalik zone. The mudstone beds of the upper Siwalik contain many
invertebrate fossils, including the fossils of Brachiopods and Gastropods. Brachiopods are the
marine animals that have hard valves on the upper and lower surfaces. These animals evolved
at least 550 MY ago. The gastropods are commonly known as snails and slugs.

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Some Fossils in Collection at the Natural History Museum (NHM)

The Natural History Museum (NHM) in Kathmandu was established in 1975. Since then it
has provided with more than 50,000 specimens of Nepal's modern and prehistoric plants and
animals. Some 964 fossils from the territory of Nepal are preserved in it. On December 31,
2013, the Department of Postal Services of Nepal issued a set of four stamps showing fossils of
extinct animals which are in the collection of the Natural History Museum (NHM). They are
briefly described below:

a. Giraffa punjabiensis

It is an extinct giraffe. The genus Giraffa evolved almost 25 million
years ago. The extinct Giraffa punjabiensis inhabited in large parts of
Eurasia, including the ancient land of Nepal. The molar teeth of this
extinct Giraffe are in collection of the NHM. The teeth were found on
the banks of Surai Khola.

b. Archidiskidon planifrons

It is an extinct elephant. Many fossilized body parts of the elephant,
Archidiskidon, were recorded from different parts of Nepal. There is
a fossilized skull of the Archidiskodon at the NHM. This species of
elephant roamed the Siwalik Hills of Nepal around 3 million years
ago. It was found on the banks of Rato Khola.

c. Ramapithecus sivalensis

It is an extinct humanoid. The fossil remains of this animal is
estimated to be 12.5 million to 8.5 million years old. The molar teeth
of the ancient hominoid Ramapithecus which is in the collection of the
NHM is estimated to be 9.0 – 9.5 MY old. It was discovered in Tinau
Khola on way to Tansen from Butwal. Ramapithecus was understood
to have direct ancestral roots to modern humans.

d. Hexaprotodon sivalensis

It is an extinct Hippopotamus. The fossil remains of this animal is
estimated to be 5.35-0.11 MY old. Fossils of this species have been
found in Indonesia, India, Sri Lanka and Nepal. In Nepal the fossils
of Hexaprotodon sivalensis were discovered at Gidniya Village and Rato
Khola. The skull and lower jaw of this extinct hippopotamus are also
in the collection of the NHM.

Estimation of Age of Rocks

Age of the rocks can be determined with the help of different methods. Relative dating and
absolute dating are the two effective methods to estimate the age of rocks.

Relative dating method

Relative dating is the science of determining the relative age of rocks comparing with another,
without determining their absolute age. In this method the fossils and layers of rocks are
placed in an order from older to younger. It can only establish whether one rock is older or
younger than another.

Geology and Astronomy 0Science - 10 375

Absolute or numeric dating method

Absolute dating is the process of determining specific age of rocks independently without
comparing with others. Absolute dates for rocks are obtained with radiometric dating.

Radiometric Dating or Radioactive Dating

Radioisotope is a form of an element with an unstable nucleus. For example, uranium-238
(U238), carbon-14 (C14), etc. Atoms of a radioisotope become atoms of other elements as their
nucleus disintegrates. It is called radioactive decay. Thus, the process of nuclear disintegration
is called radioactive decay. For example, radioisotope of uranium-238 (U238) decays into
thorium-234 (Th234). The predictable products of radioactive decay are called daughter
elements. In the radioactive dating, the age of rocks is determined from the decay of their
radioactive elements. The method of finding age of a material by measuring its content of
radioisotope and daughter elements is called radiometric dating. It is also called radioactive
dating. In this method, a radioactive isotope with known half-life is considered in counting to
establish the absolute age of the fossil or rock.

Half-life

The time taken to decay half of a sample of radioisotope is called half-life. For example, the
half-life to decay U238 to Pb206 is 4.5 billion years.

Radiometric Dating Techniques

The most well-known way to determine the age of rocks and fossils is through the use of
radiometric dating. In most cases, the radiometric dating techniques use the rate of change of
elements into isotopes. Sometimes, the fossils themselves are not dated. Instead of fossils, the
rocks around the fossils are dated to estimate the age of the fossils. Some of the commonly
used techniques are: Radiocarbon dating (use carbon-14 isotope), Uranium-lead dating (use
lead-206 and lead 207 isotopes), Uranium-thorium dating, Potassium-argon dating, Argon-
argon dating, etc.

The time in year which shows how long ago a rock was formed is called absolute age of a rock.
In radiometric dating, half-life of a radioisotope is applicable to find absolute age of a rock.
Parents and daughters for uranium and carbon isotopes and the corresponding half-life are
given in the table below.

Unstable Radioisotope More stable breakdown product Half-life (in years)
(Parent) (Daughter)
4.47 billion
Uranium-238 Lead-206 700 million
Uranium-235 Lead-207 5730±40
Carbon-14 Nitrogen-14

Radio-Carbon Dating

Isotopes are the different atoms of an element with different number of neutrons in their

nucleus. The three isotopes of carbon are ₆C12 (nucleus containing 6 protons and 6 neutrons),

₆C13 (nucleus containing 6 protons and 7 neutrons), and ₆C14 (nucleus containing 6 protons

and 8 neutrons). Among these ₆C12 and ₆C13 are stable in nature. Such carbon atoms occupy

almost 99.99% of total carbon existence in nature. The isotope ₆C14 is highly radioactive. So the

carbon dating method uses ₆C14 isotopes which continuously undergo decaying into stable

₇N14 atoms by releasing β-particles with the half-life of 5730±40 years. Thus, the use of ₆C14

isotope to determine the age of organic materials which contain abundant carbon is known as

radio-carbon dating.

0376 Science - 10 Geology and Astronomy

Natural production of ₆C14 in the atmosphere

₆C14 is continually being formed in the cosm1c,adlat1on co, ---+
atmosphere by the effect of cosmic ray I
neutrons on nitrogen 14 atoms. The neutron
from cosmic rays knocks a proton from e nau11on
nitrogen-14 atoms and forms C-14 atom.
I

14
- N - o proton

•I "er

₇N14 + ₀n¹ ₆C14 + 1p1 atmospheric. gasses

0'

fig: ₆C¹⁴ in living beings

The highest rate of ₆C14 production takes place in upper region of troposphere at altitudes of

9 km to 15 km.

₆C14 in living beings

₆C14 is chemically identical to the other two isotopes of carbon. It quickly combines with the
oxygen in the atmosphere to form CO₂. Photosynthesis incorporates ₆C14 into plants and then
enters into the body of animals that eat the plants. ₆C14 gets dissolved in water and enters
in the oceans, lakes and rivers. From there it assimilates into aquatic organisms. Organisms
exchange carbondioxide with atmosphere throughout their life by respiration and excretion.

Decay of ₆C14

When a plant or animal dies it no longer 100% 50% 25% 12.5%

exchanges CO₂ with the atmosphere. It stops

the entrance of ₆C14 into the body of organisms.

This starts the radioactive decay. ₆C14 atom

decays by emitting an electron. This process Age 0 Age 5730 yr Age 11,460 yr Age 17,190 yr
converts a neutron to a proton and ₆C14
converts back to its original ₇N14 form. fig: Estimation of age on the basis of half-life

By knowing how much carbon 14 is left in a sample, the age of the f17050~ Carbon•14
organism when it died can be known. ₆C14 atoms decay at the rate of 50%
every 5,730 years. So after 11,460 years 25% will be left, after 17,190 years E 50
12.5% will be left, and so on. The graph alongside shows the relation ~
between the percentage carbon-14 atoms left in the sample and the .. 25

0

,I\","'$. ~re,,.,(:) '!a(:) ~(:) n(,:) ~(:)

~ ~'bro years

corresponding age.

Memory Plus

The duration of half-life of ₆C14 is only 5730±40 years. So radiocarbon dating method is
appropriate to find the age of the rock or any carbon containing sample which is not older
than 62,000 years only.

Uranium-Lead Dating

Uranium-Lead dating method uses U238 as a parent element whose daughter product is

92

82Pb206 with half-life of 4.47 billion years. It also uses U235 as a parent element whose daughter

92

product is 82Pb276 with half-life of 710 million years. The number of parent element decreases

with time. On the other hand the product atoms keep increasing. Uranium decays into lead at

a predictable rate. By finding the ratio of parent and daughter products, the time of the origin

of the rock can be determined.

Geology and Astronomy 0Science - 10 377

Estimation of age of the mineral Zircon

Zircon consists primarily of zircon silicate. Some molecules in a zircon crystal have uranium
atoms instead of zirconium atoms. If a zircon crystal consists lead in it then the lead is
radiogenic which is formed by the radioactive decay of uranium. Uranium decays into lead at
a predictable rate. Thus, the number of uranium atoms from zircon crystal decreases with time
when they change into lead. During this decay, lead atoms accumulate in the crystal. Finally,
the ratio of uranium atoms to lead atom in a zircon crystal is used to calculate how long ago
the crystal formed. The ratio of uranium atom to lead atoms in a zircon crystal gives its age.

Mathematically,

100% of parent isotopes = newly formed rock (0Year)
50 % of parent isotopes = one half-life = 4.5 billion years
25 % of parent isotopes = two half-life = 2×4.5 billion years

Memory Plus

Uranium-Lead dating is one of the oldest method in the history of radioactive dating of
rocks and minerals that were formed about 1 million years to over 4.5 billion years ago.

The oldest known terrestrial rock, a tiny zircon crystal from Australia, is 4.404 billion
years old.

Uranium-lead radioactive dating can also be used on baddeleyite, monazite minerals.

Uranium-thorium dating method

Uranium-thorium dating is also called thorium-230 dating. In this method, an isotope
of uranium (92U234) is decayed into thorium (90Th230) with half-life of about 80,000 years. In
between uranium and thorium, uranium is water soluble whereas thorium is not. Due to this
hydrophilic and hydrophobic natures of uranium and thorium isotopes respectively, they are
used selectively into the ocean floor sediments. The age of the rocks is calculated by finding
their ratios (uranium-234/thorium-230).

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Answer writing skill

1. Write the name of the five major tectonic zones in Nepal.

The five major tectonic zones in Nepal are: Terai (Gangetic plain), Sub-Himalayan Zone
(Siwalik), Lesser Himalayan Zone, Higher Himalayan Zone, and Tibetan-Tethys Zone.

2. Name two precious gemstones found in Nepal.

Ruby and Sapphire are the two precious gemstones found in Nepal.

3. Name the fossils collected at the Natural History Museum (NHM) Nepal.

The fossils collected at the Natural History Museum (NHM) Nepal are Giraffa
punjabiensis, Archidiskidon planifrons, Ramapithecus sivalensis and Hexaprotodon
sivalensis

4. 'Nepal is rich in natural resources but their exploration and exploitation is challenging.'
Justify this statement in two points.
a. Nepal has a rough irregular surface with difficult mountain terrain.
b. There is a lack of skilled manpower, infrastructure and financial support.
So exploration and exploitation of mineral resources are still challenging in Nepal.

5. Write uses of marble, granite and slate.
a. Uses of Marble: It is used for bathroom floors, wall covering and many other
decorative purposes in the residential and commercial buildings.
b. Uses of Granite: Polished granite is used in flooring tiles, stair trades, kitchen
countertops and many other decorative features.
c. Uses of Slate: It is particularly used as roofing material. Slate tiles are used for
flooring, stairs, walkways, etc. It is also used for blackboards and writing slates.

6. Which types of mineral resources are found in different geological regions of Nepal,
explain.
Nepal is rich in mineral resources. Gravel, sand, ground water, petroleum and natural gas
are found in the southernmost Terai plain. The Sub-Himalaya region has construction
materials, radioactive minerals, petroleum, natural gas and minor amount of petrified
coal. Likewise, metallic minerals mainly iron, copper, lead, zinc, etc., industrial minerals
like magnesite, phosphorite, limestone, dolomite, talc, kaoline, graphite, etc., gemstones
and fuel minerals like coal, methane gas, petroleum and natural gas are found in the
Lesser Himalaya zone. Some of the areas in Higher Himalaya are highly promising for
precious and semiprecious stones like ruby, sapphire and emerald, and metallic minerals
like lead, zinc, uranium, gold silver etc. Tibetan Tethys zone possesses limestone,
gypsum, brine, radioactive minerals and natural gas.

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Exercise

1Step

A. Define

1. Mineral 2. Ore 3. Gemstones

4. Radioisotopes 5. Half-life

B. Very Short Answer Questions

1. What are the five geographic divisions of Nepal from north to south?
2. Name any four metallic minerals found in Nepal.
3. Write the name of any two dimension stones found in Nepal.
4. Name two gem stones found in different localities of Nepal.
5. What are fossils?
6. Name any two fossils of extinct animals found in Nepal.
7. What are Shaligrams?
8. Write two methods to determine age of rocks.
9. What is carbon dating?
10. Write any three radiometric methods to determine age of rocks.

2Step

A. Short Answer Questions

1. Mention any two special features of following zones of Nepal.

a. Terai b. Sub Himalayan Zone

c. Lesser Himalayan Zone d. Higher Himalayan Zone

e. Tethys Himalayan Zone

2. Write two localities each of the following metallic minerals found in Nepal

a. Iron (Fe) b. Copper (Cu)

c. Gold (Au) d. Silver (Ag)

3. Write two localities each of the following non-metallic minerals found in Nepal

a. Limestone b. Dolomite c. Phosphorite d. Magnesite

e. Talc f. Red Clay g. Ceramic clay or Kaolin h. Graphite

4. Write about followings:

a. Cephalopod Fossils in Nepal

b. Brachiopod and Gastropod Fossils in Nepal

5. Write in short about any two extinct animals whose fossils are in the Natural History Museum

(NHM).

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6. How is the status of fuel minerals in Nepal?
B. Differentiate Between
1. Radiocarbon dating and Uranium-lead dating
2. Relative dating method and absolute dating method
C. Give Reason
1. Kaolin is also called China clay
2. Radiocarbon dating method is appropriate to find the age of the rock which is not older than

62,000 years only.

3Step

1. Write applications of decorative stones found in Nepal.
2. Exploration and exploitation of gemstones found in Nepal can be a source of national

economy. Illustrate this with example.

3. Nepal has a huge potential of natural resources. Illustrate it with three supporting points.

4Step

1. Explain about the geologic diversity of Nepal.

2. How is the status of following minerals in Nepal, explain in brief.

a. Metallic minerals b. Non-metallic minerals

c. Decorative stones d. Gemstones

3. Explain in short about the uranium-thorium dating to find the age of rocks.

4. Compare radiocarbon dating with Uranium-lead dating and Uranium-thorium dating

individually.

5. Explain in short about the carbon dating to find the age of fossils.

6. Mention the role of Natural History Museum (NHM) in preserving the different fossils found
in Nepal.

Multiple Choice Question (MCQs)

1. The non-metallic mineral composed of calcium magnesium carbonate is

a. Limestone b. Dolomite

c. Phosphorite d. Magnesite

2. In Nepal, ammonites are abundantly found in

a. Mustang b. Manang

c. Dolpa d. Ilam

3. The Natural History Museum (NHM) in Kathmandu was established in

a. 1965 b. 1975

c. 1985 d. 1995

4. The half-life of the decay U238 to Pb206 is

a. 4.47 billion years b. 2.5 billion years

c. 5.5 billion years d. 3.5 billion years

5. In Uranium-Lead Dating, the parent element used is

a. U235 b. Pb206

c. Pb238 d. U238

Geology and Astronomy 0Science - 10 381

UNIT

20 THE
UNIVERSE

Edwin Powell Hubble (1889–1953) was an American astronomer. He studied law in
Bachelors and got Bachelor of Science degree in 1910. He earned his Master's degree from
The Queen's College, Oxford. Hubble played a crucial role in establishing the fields of
extragalactic astronomy and observational cosmology. He is regarded as one of the most
important astronomers of all time. Hubble's Law implies that the universe is expanding.
Hubble's name is most widely recognized for the Hubble Space Telescope which was
named in his honor.

Key terms and terminologies of the unit

1. Universe: The vast space consisting of everything like stars, planets, minor
planets, moons, galaxies, energy, time, etc. is called the universe.

2. Constellation: The small group of stars seen in the sky especially at night with
fixed shape is called constellation.

3. Space Exploration: Space exploration is the ongoing discovery and exploration
of the celestial structures in outer space by means of continuously evolving and
growing space technology.

4. Artificial Satellite: An artificial satellite is an object that people have made and
launched into orbit using rockets.

5. Spacecraft: A spacecraft is a vehicle, or machine designed to fly in outer space.

6. Robotic spacecraft: A robotic spacecraft is an unmanned vehicle or machine
designed to fly in outer space.

7. Space probe: An unpiloted, unmanned device sent to explore space and gather
scientific information is called a space probe.

8. International Space Station (ISS): The International Space Station is a spacecraft
capable of supporting crewmembers while orbiting around the earth as like a
satellite in the low earth orbit.

9. Space shuttle: Space shuttle is a rocket-launched reusable spacecraft designed to
transport people and cargo between the earth and space.

10. Planetarium: A planetarium is a theatre built primarily for presenting educational
and entertaining shows about astronomy and the night sky, or for training in
celestial navigation.

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Introduction

On a clear, dark night, our eyes can see so many stars in the sky. They all are in a negligibly
small dimension of the universe. The vast space consists of everything like planets, moons,
minor planets, stars,galaxies, intergalactic space, energy and time is called the universe.
Mysteries of the universe kept some people busy in thinking about revealing the facts behind
it. One of the common idea of all time was a close obervation of the celestial masses and the
phenomena by going far away from the earth's surface.

The concept of propelling light man-made stuffs in air begin with ancient civilization. Later on
the advancement in technology made it possible to propel heavy stuffs like messile, rockets,
satellites, etc. in the sky. Here in this unit you will go through a brief historical background of
the space exploration. You will also learn about the telescope used to observe the outer space
and planeterium.

Space Exploration

Space exploration is the ongoing discovery and exploration of celestial structures in outer
space by means of continuously evolving and growing space technology. The study of space
is carried out mainly by astronomers with telescopes. But the physical exploration of space is
conducted both by unmanned robotic spacecraft and human spaceflight.

History of Space Exploration

We look up at the sky and wonder about the sun, moon, stars, and celestial events. Since ancient
times, people around the world have tried to unfold the mystery of outer space. But their
work was just in prediction and the earth-based observations without using advanced space
technology. The space exploration became more scientific with the technological advancement
in the 20th century. It began in the late 1950s with the development of powerful rockets. After
that, hundreds of satellites, investigations and space shuttles have been launched. They have
explored near-earth space. A permanent space station is in the orbit around the earth. Now
astronomers have collected a lot of information about the outer space. They are still working
continuously in their missions of the space exploration. The future exploration includes
building a colony on Mars, searching for life in other galaxies and other exciting programmes.

Space Exploration Idea from the Military Use of Rockets

The Chinese used rockets for ceremonial and

military purposes centuries ago. In the history

of true use of rockets, Chinese used gun powder ~ II I! .
fire-arrows as a simple form of a solid-propellant
rocket in 1232 in war with Mongols. fig: chines fire-arrows

With the fall of Germany in World War -II (1939-1945), many German rocket scientists reached

the United States (US). Others went to the Soviet Union (USSR). Both the United States and

the Soviet Union realized the potential of rocket as a military weapon. They began a variety

of experimental programmes. They engaged in a long competition to develop rockets for both

warfare and the exploration of space.

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Father of Modern Astronautics
The science and technology of space travel and exploration is called astronautics. In 1898,
Konstantin Tsiolkovsky (1857-1935) proposed the idea of space exploration by rocket. He was
a Soviet rocket scientist and pioneer of the astronautic theory. In a report published in 1903,
he suggested use of liquid propellants for rockets in order to achieve greater range. For his
ideas, careful research and great vision, Tsiolkovsky has been called the father of modern
astronautics. During the same period designing rocket engines for spaceflight occurred
simultaneously in the other two countries too. In United States, by Robert Goddard; and in
Germany, by Hermann Oberth.

The V-2 rocket

In the 1930s and1940s Nazi Germany saw the possibilities of using long-distance rockets as
weapons. The first rocket which could fly high enough to get into space was the V-2 missile
which was first launched by Germany in 1942. In World War II, London was attacked by
200-milerange V-2 missiles, which arched 60 miles high over the English Channel at a speed
more than 3,500 miles per hour.

Two- Stage rocket: The Bumper 8

A new chapter in space flight began in July 1950 with the launching of the Bumper 8. It was
built by the United States.

The Start of Space Race

The Space Race refers to the 20th century Cold War between the United States and the Soviet
Union to develop aerospace capabilities, including artificial satellites, unmanned space
investigations and human spaceflight. It begun in 1955 when both the countries announced
that they would soon be launching satellites into the orbit around the earth.

The world's first satellite; 'Sputnik 1' was launched on October 4, 1957 by the Soviet Union
(USSR). Sputnik 2 was launched on November 3, 1957. It carried a dog named Laika, which
became the first animal to reach space. The experiment aimed to prove that a living passenger
could survive being launched into orbit. But the dog was said to have died within hours due
to overheating.

The first U.S. satellite, 'Explorer 1', went into orbit on in January 31, 1958. Alan Bartlett Shepard
became the first American astronaut into space on May 5, 1961. His sub-orbital flight was of
15-minutes.On February 20, 1962, John Glenn’s historic flight made him the first American to
orbit Earth.

Memory Plus

Following the Sputnik 1, Explorer 1 was the first satellite launched by the United States
on January 31, 1958. But it entered the earth's atmosphere and burnt on March 31, 1970.

The Soviet Space Programme achieved many successes including the first living being in
orbit in 1957, the first human spaceflight in 1961. Soviet cosmonaut Yuri Gagarin was the
first human being to travel into space. On April 12, 1961, he was launched into orbit on the
spacecraft Vostok 1. The flight was of 1 hour 48 minutes to orbit the planet. Gagarin reached
an altitude of 327 kilometers (about 202 miles). After this achievement a "space race" quickly
developed between the United States and the Soviet Union.

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The United States was upset that the Soviets always seemed to be the first in everything in
the space programme. Therefore, the U.S. made the goal to land on the moon first. “Landing
a man on the moon and returning him safely back to Earth within a decade” was a national
goal set by President John F. Kennedy in1961. The United States finally succeeded in landing
the first humans on the moon on July 20, 1969 with Apollo 11. Neil Armstrong became the
first men on the moon and then Buzz Aldrin. These efforts are often taken as landmarks for
space exploration. Six Apollo missions were carried out to explore the moon between 1969 and
1972. While the United States focused on the manned Apollo programme, the Soviet Union
conducted unmanned missions that deployed rovers and returned samples to the earth. While
the United States focused on the manned Apollo programme, the Soviet Union conducted
unmanned missions that deployed rovers and returned samples to the earth.

Fact with reason

Many space missions are more suited to robotic spacecraft than the crewed operation, why?

In comparison with the crewed spacecraft, robotic spacecraft have lower cost and lower
risk factors. In case of some planetary destinations such as Venus, the vicinity of Jupiter,
etc. are too hostile for human survival. Outer planets such as Saturn, Uranus, and
Neptune are too distant to reach with current crewed spaceflight technology. So robotic
spacecraft are the only way to explore them.

A Priority Shift from one-off Flights to the Renewable Hardware

After the first 20 years of exploration, focus shifted from one-off flights to renewable
hardware, such as the Space Shuttle programme and Space Station. Skylab. Skylab was the
first United States space station launched and operated by NASA, and occupied for about 24
weeks between May 1973 and February 1974 – the only space station the U.S. has operated
exclusively. In 1979 it fell back to Earth. The Soviet programme continued to break ground in
science with the Mir space station. Mir was the first modular space station and was assembled
in orbit from 1986 to 1996. It was the largest artificial satellite in the orbit, succeeded by the
International Space Station after Mir's orbit decayed.

International Space Station (ISS)

The International Space Station (ISS) is fig: International Space Station (ISS)
a spacecraft capable of supporting crew
members while orbiting around the
earth as like a satellite in the low earth
orbit. It is a large space station that
orbits 354 kilometers above the earth.
There are astronauts and cosmonauts
living on board of the ISS right now.
Other spacecraft like 'space shuttle's
orbiter' can be docked on space station
to carry astronauts to and from the
International Space Station.

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The first piece of the ISS was launched in November 1998. But in November of 2000, the
International Space Station opened its doors to the first visitors, astronauts and cosmonauts.
Several more pieces have been added since then. The expansion of ISS has not completely
finished yet. New sections will be added to the ISS in the next few years. Russia, the United
States, and 14 other countries are now working together on the International Space Station
project.

Memory Plus

First Crew to the International Space Station were launched on October 31, 2003.

Space Shuttle

Space shuttle is a rocket-launched reusable spacecraft SOLID
designed to transport people and cargo between the earth ROCKET
and space. It is used to make repeated journeys between
the earth and space to carry up astronauts, sometimes a
satellite or other equipment into orbit. The first launch of
the Space Shuttle Columbia occurred on 12 April 1981,
exactly 20 years after the first manned space flight. It was
the orbiter Columbia, with two crew members lifted off
from the Kennedy Space Center.

The Space Shuttle programme was the United States fig: Launching of space shuttle
government's manned launch vehicle programme,
administered by NASA from 1972 to 2011. Throughout
this time, the space shuttle launched for 135 missions. Each
mission lasted for one or two weeks. The space shuttle was
made of three main parts: the orbiter, the external tank
and the solid rocket boosters. It was launched like a rocket
but landed like a glider airplane.

The Buran spacecraft was a space shuttle developed fig: Landing of space shuttle
by the Soviet Union in response to NASA's space
shuttle programme. Since 2011, when the Space Shuttle
programme was retired, NASA has been entirely
dependent on Russia for transporting its astronauts to
and from the space station. In 2014, NASA had revealed
that Boeing and SpaceX will build America's first private
spacecraft to carry astronauts to and from the International
Space Station by 2017.

Space Shuttle Disasters

Challenger Disaster: The space shuttle Challenger was NASA's second shuttle to reach
space, in April 1983. It successfully completed nine milestone missions. On its 10th
launch, on Jan. 28, 1986, the shuttle exploded 73 seconds after liftoff, killing the seven
crewmembers.

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Columbia Disaster: On Feb. 1, 2003, space shuttle Columbia broke up as it returned to
Earth, killing the seven astronauts on board. It was the second space shuttle disaster
after the challenger disaster. The Columbia disaster directly led to the retirement of the
space shuttle fleet in 2011.

Some of the Major Space Missions to Planets/ Solar System

Since 1957 earth-orbiting satellites and robotic spacecraft journeying away from the earth
have gathered valuable data about the sun, earth, other bodies in the solar system and the
universe beyond. By the early 1970s orbiting communications and navigation satellites were
in everyday use, and the Mariner spacecraft was orbiting and mapping the surface of Mars.
By the end of the decade, the Voyager spacecraft had sent back detailed images of Jupiter and
Saturn, their rings, and their moons.

In 1980s satellite communications expanded to carry television programs, and people were
able to pick up the satellite signals on their home dish antennas. Satellites discovered an ozone
hole over Antarctica, pinpointed forest fires, and sent photographs of the nuclear power plant
disaster at Chernobyl in 1986. Space telescopes like Hubble Space Telescope(HST) have found
new stars. Their exploration gives us a new view of the galaxies in the universe.

Robotic spacecraft have landed on the moon, Venus, Mars, and the asteroid Eros. They have
visited the vicinity of all major planets, and flown by the nuclei of comets, including Halley’s
Comet. Scientists have used space-derived data to deepen human understanding of the origin
and evolution of galaxies, stars, planets, and other cosmological phenomena.

Astronomical Telescope

An astronomical telescope is an optical instrument which is used to see the magnified image
of distant heavenly bodies like stars, planets, satellites and galaxies etc. It is designed to gather
light rays as much as possible from the celestial bodies which helps to observe the fine details.

Types of Astronomical Telescope
There are two basic types of astronomical telescopes. They are refractors telescope and
reflectors telescope.

Refractor telescopes
Refractor telescope is a telescope that uses lenses and their ability to refract light rays to observe
and magnify distant objects. It uses two glass lenes. The large lens is the light gathering lens.
This lens is called the objective lens. The small lens is called eyepiece. This lens determines the
magnification of the telescope. Eyepiece is replaceable in most modern telescopes.

Advantages of refractor telescope

a. Refractor telescopes are strongly made and its glass lenses need little to no maintenance.

b. The glass surface inside the tube is sealed from the atmosphere so it rarely needs
cleaning.

c. Air currents and effects due to changing temperatures in observation through a

refracting telescope are eliminated.

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Disadvantages of refractors telescope

a. Different wavelengths of light are brought to focus at different points due to the glass

in the objective lens refracting the different wavelengths to different degrees. Due

to the wave nature of light, the longer

wavelength light is bent less than the

shorter wavelength light as it passes

through the lens. This effect is called

chromatic aberration. fig: chromatic aberration

b. The objective lens can be supported only at the ends. The glass lens will sag under its
own weight.

c. It has very high initial cost relative to a reflector telescope.

Reflector telescopes

Reflecting telescopes use a curved mirror

(a parabolic mirror) to focus light onto a

second mirror, which is then sent to the

eye. A reflector telescope uses a mirror

as its objective. The mirror is close to the

rear of the telescope and light is reflected

as it strikes the mirror. All celestial objects Secooda,y mirror Primary (objective) mirro

(including those in our solar system) are so fig: Reflector telescope

far away that all of the light rays coming from them reach the Earth as parallel rays. Since the

light rays are parallel to each other, the reflector telescope’s mirror has a parabolic shape. The

parabolic-shaped mirror focuses the parallel light rays to a single point.

Advantages of reflector telescope

a. Mirrors in a reflecting telescope do not cause chromatic aberration. This is because all
wavelengths will reflect off the mirror in the same way.

b. The objective mirror is supported all along the back side so they can be made very big too.

c. Reflector telescopes are cheaper in comparison to refractor telescope of the same size.

Disadvantages of the reflector telescope

a. Its mirrors need to be recoated every few years.

b. A reflector telescope’s tube is open to the outside so its mirrors have to be cleaned
frequently.

c. The secondary mirror is used to redirect the light into a more convenient viewing spot.
The secondary mirror and its supports can produce diffraction effects.

Uses of astronomical telescope

The purpose of a telescope is to:

Gather light: This is done by using a large aperture lens or mirror. Refractor telescopes gather
light based on the size of objective lens. The amount of light gathered in it depends on the area
of the lens used. The larger the objective the more light it gathers. This helps to resolve the
fine details.

0388 Science - 10 Geology and Astronomy

Magnify the image: This is done by using a lens or mirror with a long focal length. Larger
telescopes can magnify more than 200x, making small objects like planets appear large enough
so we can see details on the surface.

Magnification of a telescope

The actual magnification of a telescope is given by the formula:

magnification = focal length of objective (F)
focal length of the eyepiece (f)

Solved Numerical:

Calculate the magnification of a telescope with an objective of focal length 120 cm
using two different eyepieces each of focal length 20 mm and 10 mm.

Solution: Here, focal length of the objective lens (F)= 120 cm

focal length of the first eyepiece (f1) = 20 mm = 2cm
focal length of the second eyepiece (f2) = 10 mm = 1cm
Now, magnification for the first case = 120/₂ = 60x

Magnification for the second case = 120/1 =120x

Constellation

The small group of stars seen in the sky especially at night with fixed shape is called
constellation. We can see constellations in the northern and southern sky at night. The ancient
people of many civilizations named the constellations of northern and southern hemispheres.
They are named after characters from classical mythology and various common animals and
objects. Some examples of northern hemispheres constellations are Leo, Pisces, Ursa Major,
Cassiopeia, Andromeda, etc. and some examples of southern hemispheres constellations are
telescopian, Musca, Tucana, etc. There are 88 constellations covering the entire sky in the
northern and southern hemispheres. Out of 88 constellations, 12 constellations comprise the
zodiac sign.

On the basis of rotation of the earth and its axial tilt, stars and constellations are divided
into two groups as circumpolar constellations and seasonal constellation. Which stars and
constellations will be circumpolar and which will be seasonal depends on latitude of the earth.
The circumpolar constellations are a group of constellations that are always visible in the night
sky of the Northern Hemisphere or Southern Hemisphere. Some constellations can be seen
from both hemispheres but at difference watch time. They are seasonal constellations.

Constellation map helps to observe constellations in night sky. We can find the position of
pole star (Dhruva Tara) in northern sky. It is the brightest star in the northern night sky. Pole
star is directly above the North Pole on the axis of rotation of earth. So, all constellations
appear to revolve around the pole star which remains stationary throughout the year.

How to locate Pole star with the help of Ursa Major?

Pole star or Polaris (Dhurbatara, in Hindu mythology) is the closest star to the north
celestial pole. The other northern circumpolar constellations appear to revolve around
Polaris from east to west direction. It is the brightest star on the tail of Ursa Minor.

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The position of the pole star can be easily located with the help of the constellation Ursa Major.
To find Polaris, first find the Big Dipper. Imagine a line drawn connecting the right edge of
the "bowl" i.e. line in between Merak and Dubhe. If you extend the line north, it will come to
the brightest pole star.

Zodiac Constellations

When we observe in the clear sky from morning to the evening, the sun seems to move along a
certain path in the sky, from the eastern horizon to the western horizon. The path along which
the sun seems to move in the sky is called the ecliptic path or solar path. During the night,
when the constellations are visible, if we observe in the sky, we can see 13 constellations that are
along the solar path. Out of these 13 constellations, 12 of them have astrological significance.
These 12 constellations are called zodiacs. Zodiac or Rashi are the 12 constellations in the
sky that lie in the solar path and have certain astrological significance. The names of these 12
zodiac constellations are:

1. Aries 2. Taurus 3. Gemini 4. Cancer

5. Leo 6. Virgo 7. Libra 8. Scorpius

9. Sagittarius 10. Capricorn 11. Aquarius 12. Pisces

fig: Zodiac Constellations

In several religious practices, a born child is given a zodiac sign that is expected to determine
his/her fate. These signs are given according to the position of the stars. Stars change their
relative position in the sky and do not remain constant throughout the year. The determining
fate and so called luck on the basis of zodiac is a superstition and has no scientific grounds.

Circumpolar Constellations and Seasonal Constellation

On the basis of rotation of the earth and its axial tilt, constellations are divided into two groups
as circumpolar constellations and seasonal constellation.

Circumpolar Constellation

Constellations that never set below the horizon from the viewer's perspective are called
circumpolar constellation. Such constellations do not rise and set. They are visible all year
long from that hemisphere.

i. Northern hemisphere constellations.

Constellations that never set below the horizon from the viewer's perspective

in the northern hemisphere are called northern hemisphere constellations.

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The five main northern circumpolar constellations are Ursa Major, Ursa Minor, Draco,
Cepheus and Cassiopeia. Northern hemisphere constellations appear to be revolving
around the pole star which remains stationary throughout the year.

Fact with reason

The pole star remains stationary throughout the year, why?

Pole star is straight above the North Pole on the axis of rotation of earth. So the pole
star remains stationary throughout the year.

ii. Southern hemisphere constellations.

Constellations that never set below the horizon from the viewer's perspective in the
southern hemisphere are called northern hemisphere constellations. Some examples of
southern hemispheres constellations are telescopian, Musca, Tucana, etc.

Seasonal constellations.

We can't see all the constellations every night of the year. This is due to both our position on
the earth (i.e. latitude) and revolution of the earth around the sun (i.e. the position of the sun
through the sky). The stars are always up in the sky. They are not visible to our eyes during
the day due to the brightness of the sun. In winter season and in summer season, the earth is
at two just opposite positions on its orbit. The part of the Milky Way which was observed in
night time in winter season crosses the sky during day time in the summer season.

A constellation that is only above the horizon for a part of the year and becomes visible seasonally
is called seasonal constellation. All constellations other than circumpolar constellations are
seasonal constellations. For example, winter constellations (Orion, Gemini, Taurus, etc.),
Spring Constellations (Cancer, Hydra, Leo, Virgo, etc.), Summer Constellation (Sagittarius,
Scorpius, Lyra, etc.), and autumn/fall constellation (Aquarius, Capricorn, Pisces, etc.) Some of
the constellations of one season cannot be seen in the other season at the same watch time from
the same place. Some constellations can be seen from both the hemispheres too but at different
watch time. It depends on how far is a person from the equator (i.e. latitude).

Fact with reason

Some of the constellations of one season cannot be seen in the other season, why?

The Earth with its inclined axis revolves round the sun from west to east. In winter
season and in summer season, the earth is at two just opposite positions on its orbit. This
is why some of the constellations of one season cannot be seen in the other season at the
same watch time from the same place.

Preparation of a model of Constellation

In model of constellations we create constellations pattern. When we construct the model, we
have to think of the positions of the zodiacal constellations compared with the positions of
the earth in its orbit. We will use the overhead projector to display the constellation pattern
on the cardboard (only the brightest stars). For making this model more understandable we
could paint the figures of mythological creatures onto the constellations freehand or using
transparencies. We can display constellation patterns on a wall to present this model as a two-
dimensional version. It could be more illustrative as a three-dimensional version in the middle
of the class.

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Geology and Astronomy

Another way to display constellation patterns is by letting the pupils be the parts of
constellation model, each carrying a cardboard of one constellation. In this model, we need
twelve constellations, one Earth and one Sun.

Activity: Draw all 12 seasonal constellation patterns separately on A4 sized papers.
Place them around your classroom. Use a basketball to model the sun in the center. Tell
your friend to rotate to experience day and night, and walk around the sun to model the
orbit throughout the year. Make them stop in different positions throughout the year,
and ask them which constellations they would be able to see at night.

Importance of observation of constellations in daily life

1. The position of the constellation gives us an idea about time. Old people in village and
the remote areas still have an idea to find out time in the night by looking at the position
of the major constellations like Ursa Major (Saptarishi).

2. The constellations and their position change with seasons. We know about the seasonal
changes by looking at the position of the constellations. For example, when Orion starts
to become visible then it indicates winter is coming soon.

3. The constellations help in navigation. It is fairly easy to spot Polaris, the North Star. With
reference to this, other constellations can also be identified, which helps navigators to
travel across the globe.

4. Study of the constellations helps us to locate other heavenly bodies in the sky like the
position of the comets, meteors, etc.

5. Constellations have a religious value. Many cultures believe that the positions of
constellations are according to the God's will.

6. In the Hindu mythology, people use the constellations to give a zodiac sign, to make
birth record (Janam Patri or Janam Kundali in Nepali language), to forecast for good

and bad omen (Grahadasha in Nepali language).

Planetarium

A planetarium is a theatre built primarily zenith

for presenting educational and

entertaining shows about astronomy

and the night sky, or for training in

celestial navigation. But instead of a big

cinema screen at the front of the room,

images are projected onto a domed

ceiling of a planetarium to create a more

immersive experience. A planetarium

can give us an amazing virtual tour of fig: Components of planeterium
the universe from the earth. Shows of

both the fixed planetarium and mobile planetarium are a resource for astronomy information.

Mobile planetariums are constructed from a durable, wrinkle free and opaque fabric. It is

inflated with a high velocity industrial floor fan or a blower. The celestial scenes can be created

using a wide variety of technologies such as slide projector, video and full dome projector

systems and lasers. Following are the planetarium basics:

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Dome: The dominant feature of a planetarium is the large dome. It is defined as the curved
surface or hemisphere where the projection is done. The main challenge while constructing a
planetarium projection dome screen is the echo of sound.

Auditorium: Planetariums have a large room, i.e. auditorium with a dome-shaped ceiling
and many seats built to receive the public during a show.

Projector: The most modern planetariums use digital projectors connected to computers.
They can project any image onto the dome to show incredible views from anywhere in the
universe. Combining data from space agencies, spacecraft and telescopes all over the world,
realistic graphical representations of entire galaxies can be projected onto the dome.

Computer and Software: Computers play the full dome content or scenarios through
software. Software with virtual model of the known universe is used for planetarium show.
A real-time astronomy software like Uniview brings scientific data to life in a planetarium.

Audio system: To ensure the most immersive environment in a modern digital planetarium,
audio system is uniquely engineered according to the dome size, tilt, seating configuration
and room acoustics. Loudspeaker reproduces the high frequencies of the sound signal and the
woofer reproduces the low frequencies of the sound signal.

Memory Plus

The term “planetarium” was initially used to represent a small model of the solar system.
The first planetarium was designed in the year 1682 by the famous astronomer Christiaan
Huygens.

B.P. Koirala Memorial Planetarium fig: B.P. Koirala Memorial Planetarium in Kiritipur, Kathmandu

B.P. Koirala Memorial Planetarium is in
Kiritipur, Kathmandu. It is established
to popularise the Science among the
students and general people. It will help
to conduct research activities in the area
of astronomy.

Advantages of a Planetarium
Following are the advantages of a planetarium:

1. Planetarium shows are a resource for astronomy information. It keeps people informed
about sky events.

2. It helps to identify the stars and the changes in the position of stars and constellations
with seasons.

3. A planetarium is the most effective teaching aid for astronomy in schools and colleges.
It is an educational device for showing the locations and movements of the planets and
other objects in the universe. Mobile planetariums for schools have made it easier for
students to understand astronomy.

4. It is also used to create awareness about science and technology and space exploration.

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Answer writing skill

1. Name the Russian space craft that put the first person into space.

Vostok

2. Which was the first manned mission to land on the moon?

Apollo 11 was the first manned mission to land on the Moon.

3. In northern hemisphere, Orion is visible on winter evenings but not summer evenings,
why?
In between the months of April and September, Orion will be in the daytime sky for the
people in northern hemisphere. But in winter and very early Spring it will be in the night
time and becomes visible to anyone in the Northern hemisphere.

4. List any four importance of observation of constellations in daily life.
1. The position of constellation gives us an idea about time. Old people in village and
remote area still have an idea to identify time in night by looking at the position of the
major constellations like Ursa Major (Saptarishi).

2. Constellations and their position changes with seasons, which helps know about
seasonal changes. For example, when Orion started to becomes visible then it indicates
winter is coming soon.

3. Constellations help in navigation. It is fairly easy to spot Polaris, the North Star. With
reference to this, other constellations can also be identified. Which helps navigators to
travel across the globe.

4. Study of the constellations helps us to locate the other heavenly bodies in the sky like
the position of comets, meteors, etc.

5. Explain in short about the space exploration and its benifits for mankind.
Since 1957 earth-orbiting satellites and robotic spacecraft journeying away from the
earth have gathered valuable data about the sun, earth, other bodies in the solar system
and the universe beyond. By the early 1970s orbiting communications and navigation
satellites were in everyday use. In 1980s satellite communications expanded to carry
television programs, and people were able to pick up the satellite signals on their home
dish antennas. Satellites discovered an ozone hole over Antarctica, pinpointed forest
fires,, etc. Communications satellites help the world stay connected. The technologies
developed with space exploration are beneficial for the contemporary world.

0394 Science - 10 Geology and Astronomy

Exercise

1Step

A. Very Short Answer Questions b. The first animal in space
1. What is a constellation? d. The first human being on
2. How many constellations are known to us?
3. Name any four constellations. the moon
4. What is meant by space exploration?
5. Who is the father of modern astronautics?
6. What is an artificial satellite?
7. What is spacecraft?
8. What is a robotic spacecraft?
9. What is a space probe?
10. Name the followings:
a. The first satellite
c. The first human being to travel into space

11. What is an astronimcal telescope?
12. What is a planetarium?

2Step

B. Short Answer Questions
1. Write in short about
a. International Space Station (ISS) b. Space Shuttle
2. Write the advantages of a planetarium.
3. Give two advantages of each refracting telescope and reflecting telescope.
4. Give two disadvantages of each refracting telescope and reflecting telescope.

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Geology and Astronomy

C. Give Reasons
1. Many space missions are more suited to robotic spacecraft than the crewed
operation.
2. A planetarium is made with a dome structure design.
3. some of the constellations of one season cannot be seen in the other season
4. Pole star remains stationary throughout the year.

D. Write Differences
1. Galaxy and constellation
2. Reflecting telescope and refracting telescope
3. Northern hemisphere constellations and Southern hemisphere constellations.

3Step

1. Mention the importance of constellations in our daily life.
2. Write in short about history of space exploration.
3. Write three benefits of space explorations for the mankind.
4. Write in short about any three components of a planetarium.

4Step

5. Present your view on the need of movable planetarium in schools.
6. Explain in short about some of the major space missions to planets.
7. How does an astronomical telescope work? Explain.
8. Mention the uses of an astronomical telescope.
9. How do you prepare a model of constellation? Explain.

Project Work

Make a table on a chart paper and note down about the space exploration missions and
present it in the classroom.

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