Full Answers Textbook Science Form 2

Chapter 1 of the dicotyledon plant have network-
like veins.
Formative Practice 1.1 (b) Monotcotyledon plants have fibrous
1. The diversity of organisms, whether roots whereas dicotyledon plants
have tap roots.
animals, plants or microorganisms.
2. Biodiversity supplies raw materials such as Summative Practice 1
1. (a) Biodiversity
timber, oil palm and rubber, herbs for the (b) Poikilothermic
manufacture of medicines and cosmetics, (c) Dichotomous
as well as places for recreation. (d) Vertebrates
3. Definition: a natural or exclusive species (e) Gills
that is found in a particular area only. (f) Iguana
Ways: Replant trees and tighten laws 2. (a) 7 (b) 3 (c) 3
(Any other answers are accepted) 3. (a) (i) Without wings
4. Orang utan// Malayan tiger// hedgehog// (ii) Thick, hard wings
mousedeer// hornbill// rafflesia// pitcher (iii) Dragonfly (Q)
plant. (iv) More than three pairs of legs
(Any other answers are accepted) (v) Body with many segments
(b) Have legs
Formative Practice 1.2 (c) Animal P has three pairs of legs,
1.
animal S has four pairs of legs
Vertebrates whereas animal T has more than four
pairs of legs.
Fish Amphibians Reptiles Birds Mammals 4. (a) Root, leaf, stem, number of cotyledons
(b) (i) Leaves with parallel veins
Eel Frog Crocodile Penguin Orang (ii) Fibrous root
(iii) Both have non-woody stem
Toad Tortoise Duck utan 5. Correct. The animals are invertebrates
because all three have no backbone.
Dolphin 6. Differences:
(i) Segmented body, not segmented body
Platypus (ii) Has legs, no legs
Dichotomous key:
2. Similarity: Both plants produce seeds
Differences: Invertebrate
(a) the paddy plant is a monocotyledon
Without segmented body With segmented body
plant whereas the sunflower plant is a
dicotyledon plant. Planaria Without legs With legs
(b) the paddy plant has fibrous roots
whereas the sunflower plant has a tap Earthworm Butterfly
root.
(c) the paddy plant has parallel vein
leaves whereas the sunflower plant
has network-like vein leaves.
3. (a) The leaves of the monocotyledon plant
have parallel veins whereas the leaves

1

HOTS Mastery 1 Activity 2.3
7. (a) To build new settlements 3. Prevent organisms from extinction
(b) To construct highways
(c) To open new industrial areas (Question 1, 2 and 4 based on student’s
(d) To open new agricultural areas findings)
8. Endemic animals are animals that are
Formative Practice 2.3
threatened by extinction. Hunting and 1. (a) Population (c) Habitat
killing these animals will cause them to (b) Community (d) Ecosystem
become extinct. Future generations will 2. (a) Competition (b) Commensalism
not know this animal if it becomes extinct. (c) Parasitism
(Any other answers are accepted)
Formative Practice 2.4
Chapter 2 1. Logging, open burning, illegal hunting,

Formative Practice 2.1 unrestricted catching of fish
(Any other answers are accepted)
1. Producer: cabbage 2. (a) (i) Destruction of habitat
(ii) Migration or death of animals
Primary consumer: caterpillar (b) (i) Increase of carbon dioxide levels

Secondary consumer: chicken in the atmosphere
(ii) Acid rain that destroys
Tertiary consumer: snake
decomposer bacteria in the
2. (a) Sparrow ground
Caterpillar (c) (i) Flow of fertiliser into rivers that
affects aquatic life
Paddy Grasshopper Owl (ii) Use of pesticides kills other
plant Rat organisms apart from the pests
(d) (i) Breeding of pests such as rats
(b) Food decreases, consumers (ii) Disposal of rubbish into drains
migrate to another place and animal causes flash floods
population decreases. 3. Rear owls to to eat the rats that destroy
crops.
Formative Practice 2.2 4. (a) Open burning/ smoke from car
1. Carbon cycle, oxygen cycle and water exhausts/ smoke from factories
(b) Cough/ flu/ asthma getting worse/
cycle limited range of vision / greenhouse
2. Evaporation and condensation effect/ global warming
3. Plants and animals use oxygen and (c) (i) Enforce laws
(ii) Conduct awareness campaigns
release carbon dioxide during respiration. (iii) Highlight the issue of haze in
Through the process of photosynthesis, school
plants absorb carbon dioxide and produce 5. (a) Protect species from extinction so that
oxygen. Apart from that, decomposition future generations can see them.
of organisms and burning of fossil fuels (b) Animals and plants are needed for
also release carbon dioxide. All these food and oxygen.
processes maintain the balance of oxygen
and carbon dioxide in the atmosphere.
4. (a) Collect rain water for everyday use

such as watering plants or washing
cars
(b) Ensure pipes are not leaking
(c) Wash cars using water in a pail
(Any other answers are accepted)

2

Summative Practice 2 Chapter 3
1. (a) Sapling ➝ Rat ➝ Fox
Sapling ➝ Rabbit ➝ Fox Activity 3.1
Grass ➝ Rabbit ➝ Fox
(b) Because grass can make its own food Activity Observation
(c) Parasitism
(d) The number of rabbits and rats will A The solution changes to dark blue

increase. B A brick red precipitate forms
The number of grass and saplings will
C A brick red precipitate forms
decrease.
2. (a) Outbreak of diseases D A white colour suspension forms
(b) Disposal of rubbish, especially food
1. To make sure the samples are at a
scraps in an unsystematic way constant temperature.
(c) (i) Scheduled collection of garbage//
2. First, mix the food sample in powder
fines form with distilled water. Then, carry out
(ii) Organise community clean-up the Iodine, Benedict, Millon and alcohol
emulsion tests.
events and cleaning campaigns.
Take care of the cleanliness 3. Activity A: The sample will change colour
of the house environment and to dark blue because of the presence of
business premises. starch.
3. Azah is correct. Without decomposers,
nutrients such as phosphorus and Activity B: A brick red precipitate will form
nitrogen will remain in the dead body because of the presence of reducing sugar.
of organisms and cannot be used by
plants. Plants become infertile and may Activity C: A brick red precipitate will form
eventually die without enough nutrients. because of the presence of protein.
4. The rat population increased because
its predator, the eagles, had been shot. Activity D: A white colour suspension will
Razak needs to breed owls at his farm as form because of the presence of fat.
a biological control to destroy the rats.
Formative Practice 3.1
HOTS Mastery 2
5. Trees absorb carbon dioxide that is 1. (a) Water, fat (c) Carbohydrate

released by vehicle exhausts to carry (b) Protein (d) Vitamin
out photosynthesis and release oxygen.
Trees are also the habitat for organisms 2. (a) Night blindness// Skin diseases
such as birds. Tree roots hold the soil and
prevent erosion. The surrounding areas (b) Beri-beri// Anaemia
become shady and the moisture in the
earth can be maintained. (c) Scurvy
6. (Accept any suitable design with
explanations) (d) Rickets // Toothache // Skin diseases

3. (a) Goiter

(b) Anaemia

(c) Rickets // Brittle teeth // Cannot build

DNA and RNA

Formative Practice 3.2
1. A balanced diet is a diet that contains all

classes of food required by the body in the
right quantities.
2. Gender, body size, health condition, age,
work and climate
3. The energy needs of a 50-year-old man is
higher because he generally does more
heavy work compared to a 50-year-old
woman.

3

4. Calorific value of food is the total energy 2. (a) Tie the Visking tubes securely
that is released when 1 g of food burns (b) Wash the Visking tubes thoroughly
completely in the body.
before putting them into the distilled
5. Total calories consumed by Suraya: water.
3. (a) Iodine solution remains brown
Food Calorific value because the size of starch molecules
(kcal) is big and cannot diffuse through the
Cornflakes Visking tube.
Milk 160 (b) Benedict's solution forms brick red
Nasi lemak (full 130 precipitate because the size of
serving) 400 glucose is small and can diffuse
Green apple through the Visking tube.
Total 60 4. Starch consists of big molecules that
750 kcal cannot diffuse through the Visking tube.
Glucose consists of small molecules that
Yes, because the breakfast eaten by can diffuse through the Visking tube.
Suraya has all the food classes and is
suitable for the activities she does. Formative Practice 3.4
1. (a) Rectum; stores faeces before it is
6. The climate in Switzerland is different
from Malaysia. The temperature in eliminated
Switzerland is much lower. More calories (b) Peristalsis movement
are required to maintain the body (c) Water
temperature there. 2. Causes constipation.

Activity 3.7 Summative Practice 3
1. 37ºC is the optimum for action of 1. (a) Eggs, meat, soy bean, chicken, fish

enzymes/ human body temperature (Any other answers are accepted)
2. Digested into maltose (b) For growth// To build cells and body
3. Amylase
tissues
Formative Practice 3.3 (c) (i) Practise healthy intake of food//

1. Digestion is the process of breaking down Exercise// Drink more plain water
(ii) Bread, chocolate milk and
large and complex food into small and
half-boiled eggs
simple molecules. (Any other answers are accepted)
(iii) Amri probably had too much
2. (a) Mouth (e) Small intestine
snacks and carbonated drinks.
(b) Oesophagus (f) Large intestine Snacks have high content of fat.
Carbonated drinks contain a lot
(c) Stomach (g) Rectum of sugar. Excessive fat can cause
obesity and excessive sugar can
(d) Duodenum (h) Anus cause diabetes.
2. (a) Consume a diet that is high in fat.
3. (a) Amylase: To digest starch (b) To keep her body warm. Excess fat
will be stored under the skin as heat
(b) Protease: To digest protein insulator.
3. (a) P: Mouth
(c) Lipase: To digest fat

4. Protease, lipase and amylase cannot

be produced. Therefore, protein, fat and

starch cannot be digested effectively.

Experiment 3.1
1. Small intestine, blood

4

Q: Liver transmits pathogens from one host to
another new host.
R: Large intestine 2. (a) Cholera
(b) H1N1// Dengue
S: Oesophagus (c) Tinea// ringworm
3. Infectious diseases: SARS// H1N1//
T: Stomach Tuberculosis// flu
Non-infectious diseases: Diabetes// high
U: Duodenum blood pressure// cancer
4. Infectious diseases are spread through
V: Small intestine vectors, and mediums such as water, air
and through contact.
W: Anus
Formative Practice 4.2
(b) (i) Mouth 1. Specific defence mechanism and non-

(ii) Stomach specific defence mechanism.
2. An antigen is a foreign substance or
(iii) Duodenum
a substance outside the body that
4. (a) (i) Food sample is placed into a stimulates the body’s immune system.
An antibody is a protein produced by
boiling tube white blood cells into the bloodstream in
response to antigen.
(ii) 2 ml of Benedict’s solution is Immunity is the ability of the body to fight
against pathogens when the body is
added infected with pathogens.
3. (a) P: Passive natural immunity
(iii) The mixture is heated using a Q: Active natural immunity
(b) Similarity: Both immunities are
water bath
obtained naturally without external
(iv) A change of colour is observed. help.
Difference: Immunity P is obtained
(b) Food Test Observation when the body receives antibodies
from breast milk or from the mother’s
Rice Iodine blood that flows across the placenta,
Benedict whereas immunity Q occurs when
antibodies are produced in an
Honey Iodine individual who has recovered from a
Benedict disease.
(c) Immunity Q is better because the
(c) Rice contains starch. Honey contains concentration of antibody in the
reducing sugars. blood remains above the immunity
level, whereas for immunity P, the
5. (a) Temperature of amylase concentration of antibody in the blood
(b) Volume of amylase and volume of drops below the immunity level after a
certain period.
starch suspension 4. Smoking, undergoing unnecessary
(c) Yes. When heated, Benedict's solution surgeries, eating imbalanced diet.

does not form a brick red precipitate in 5
boiling tube A. This shows that there
is no reducing sugar present. The
high temperature destroys amylase.
Starch cannot be broken down into
maltose.

HOTS Mastery 3
6. (a) (Student's answer)
(b) (Student's answer)
7. (a) (Student's answer)
(b) (Student's answer)

Chapter 4

Formative Practice 4.1
1. A pathogen is an organism that causes

diseases. A vector is an organism that

(Any other answers are accepted) pathogens, whereas non-specific
5. Infectious diseases are the main cause defence mechanism attacks all
pathogens.
of defect and death among babies and (b) (i) Pathogens are destroyed by
children. Immunisation is important
because it can stimulate the baby to antibodies produced by white
produce antibodies to fight against blood cells.
pathogens. Babies and children will (ii) The entrance of pathogens
be safe from infectious diseases and is prevented by the skin and
complications. mucous membranes, whereas
pathogens that have successfully
Summative Practice 4 entered the body are destroyed
1. (a) Group 1: Diabetes, hypertension, through phagocytosis.
(c) (i) Active natural immunity
heart attack, cancer (ii) Active artificial immunity
Group 2: Flu, chickenpox, (iii) Passive natural immunity
(iv) Passive artificial immunity
Leptospirosis, Zika, cholera, tinea 6. (a) Sever the transmission of infection
(b) Non-infectious diseases and by detecting the cases actively
and passively such as giving initial
infectious diseases treatment to the patients and
(c) (i) Tinea separating the patients from others.
(ii) Leptospirosis (b) (i) What activities did you do
(iii) Flu within the two weeks before the
(iv) Diabetes// hypertension// heart infection?
(ii) Did you go into the forest or swim
attack in the waterfall before getting
(d) Chickenpox sick?
2. (a) Dengue virus, Aedes mosquito (Any other answers are accepted)
(b) Zika// Chikungunya (c) (i) Avoid meeting the patients
(c) Dengue haemorrhagic fever spreads (ii) Take precautionary steps when
meeting the patients like wearing
when an Aedes mosquito bites and a face mask to cover the nose
sucks the blood of a patient who and mouth.
has dengue virus. The mosquito will (iii) Improve personal hygiene,
transmit the virus to another individual and cleanliness of house and
that it bites. environment.
3. Besides producing unpleasant smell, the (iv) Take vector control measures.
exposed garbage will attract cockroaches, (Any other answers are
flies and rats. These animals can be the accepted)
vectors for diseases such as cholera, (d) Quarantine the patients is a wise step
typhoid and leptospirosis. to prevent the public from meeting the
4. (a) The body reacts to fight viral infection patients. This is because transmission
by producing antibodies in the blood of bacteria or viruses can occur
to kill the virus. through air, water, vectors and also
(b) 16 to 17 days after the infection. through contact.
(c) The virus is killed and the body gets
immunity against the disease.
5. (a) Similarity: Both mechanisms function
to prevent infection of diseases.
Difference: Specific defence
mechanism attacks certain

6

HOTS Mastery 4 state of matter of ice changes from solid
7. a) • Inference 1: The new food causes the to liquid.
2. The boiling point of distilled water is lower
disease. than the boiling point of distilled water
• Inference 2: The new hens have mixed with salt because the presence of
impurities (salt) increase the boiling point
spread the disease. of water.
b) • Hypothesis 1: If the new food has 3. Impurities increase the boiling point and
decrease the melting point.
caused the disease, then the hens will
recover after eating the original food. Experiment 5.1
• Testing hypothesis 1: Separate the 1. Water moisturises the air in bell jar R
sick hens into a different coop. Give
the original food for all the hens. while anhydrous calcium chloride absorbs
• Observe all the hens after one water vapour in bell jar S so that the air
week. If the hens are still sick, then will become dry.
hypothesis 1 cannot be accepted. 2. The filament lamp is used as a source of
• Hypothesis 2: If the new hens have heat energy.
spread the disease, then the lab test 3. The larger the surface area exposed, the
on the blood and stool of the hens can higher the rate of evaporation of water.
prove this. 4. To increase the movement of air.
• Testing hypothesis 2: Carry out lab
test on the blood and stool of the Formative Practice 5.1
hens. 1. • Boil the water – pure water boils at
• If the results show the presence of
pathogens in the blood or stool of 100°C.
the hens, then hypothesis 2 can • Determine the density of the water –
be accepted. The hens should
be injected with antibiotics as a density of pure water is 1 g cm–3
treatment. (Any other answers are accepted)
2. The movement of water molecules at
Chapter 5
room temperature is faster than the
Activity 5.2 movement of water molecules at 0°C.
1. K – Oxygen This is because high temperature causes
L – Hydrogen the water molecules to gain more energy
2. (a) The ratio of gas K to gas L is 1:2 and move faster than the water molecules
(b) One molecule of water is made up of at 0°C.
3. Sweat glands secrete sweat onto the
one oxygen atom and two hydrogen surface of the skin to increase the loss of
atoms. heat through evaporation. Evaporation of
3. Dilute hydrochloric acid allows the current sweat cools the human body.
to flow better through water because water
is a poor conductor of electricity. Activity 5.5
1. P: Dilute solution
Activity 5.3 Q: Concentrated solution
1. Ice particles absorb heat energy from the R: Saturated solution
2. Solute – Copper(II) sulphate
surrounding and start to vibrate faster. The Solvent – Distilled water
forces of attraction between the particles Solution – Copper(II) sulphate solution
are overcome, causing the ice particles 3. Copper(II) sulphate has dissolved to the
to move faster and randomly. Hence the
7

maximum in the distilled water. Thus, the Activity 5.7
excess copper(II) sulphate remains as a 1. Distillation
precipitate. 2. Chlorine kills the microorganisms in the

Activity 5.6 water in Petri dish E.
1. The mixture of water and chalk powder 3. The nutrient agar in Petri dish B contains

looks cloudy. microbial colonies because filtration only
2. When a mixture of solute and solvent removes suspended particles but not
microorganisms. The nutrient agar in
produces a clear solution, this allows Petri dish C is free from microorganisms
light to pass through the solution. A bright because distillation removes suspended
spot of light will be observed on the white particles, dissolved substances and
screen. When a mixture of solute and microorganisms.
solvent does not produce a clear solution,
a suspension is formed. The light cannot Formative Practice 5.3
pass through. A dim spot of light will be 1. Dissolved mineral salts, solid suspended
observed on the white screen.
3. Copper(II) sulphate solution that is filtered particles and microorganisms.
does not leave any residue because the 2. Filtration and distillation
particles of copper(II) sulphate crystals (Any other answers are accepted)
(solute) dissolve evenly throughout the 3. Oil spillage and disposal of industrial
water (solvent). The mixture of water and
chalk powder leaves residue on the filter waste.
paper because the mixture produces a (Any other answers are accepted)
suspension that contains the particles of 4. (a) False (b) True (c) False
insoluble chalk powder. 5. – Develop a waste disposal system.
– Encourage the usage of
Formative Practice 5.2
1. Sugar dissolves in water forming sugar biodegradable fertiliser in agricultural
sector.
water. – Strict law enforcement
Sugar is a solute, a substance that (Any other answers are accepted)

dissolves in a liquid. Summative Practice 5
Water is a solvent, a liquid that dissolves 1. Water has a strong surface tension due to

a solute. the cohesive force between the molecules
Sugar water is a solution, a mixture of of water at the surface. Johan should
have dived into the water by keeping his
solute and solvent. hands together straight to the front, and
2. The particles of a solute in a solution both legs together straight to the back.
This can reduce the effect of surface
are dispersed evenly throughout the tension of water on him.
solvent, but the particles of a solute in a 2. (a) (i) Salt particle
suspension are dispersed unevenly.
(Any other answers are accepted) (ii) Water
3. Rust – lime juice// vinegar molecule
Blood – common salt solution
Ink – hair spray// vinegar Salt particle
4. Hot water increases the rate of solubility Water molecule
of coffee powder. The higher the
temperature of water, the higher the rate
of solubility of coffee powder.

8

(b) Yes. Heat can increase the rate of HOTS Mastery 5
movement of salt particles. Hence, the 8. (Student’s answer)
salt particles can move faster to fill the 9. – Is the mixture clear or cloudy?
spaces between the water molecules. – Is the mixture transparent?
– Does the mixture leave any residue
3. (a) The water particles at the surface
of water vibrate faster upon gaining when filtered with a filter paper?
heat energy from the surrounding and
escape from the water surface. Chapter 6

(b) Humidity, movement of air, Activity 6.1
surrounding temperature and exposed 1. pH 8 – pH 14
surface area. 2. The reaction between acid and metal

– The higher the humidity, the lower releases hydrogen gas because acid
the rate of evaporation of water. contains hydrogen ions.
3. Magnesium ribbon exposed to air will
– The higher the surrounding be oxidised. Therefore, the magnesium
temperature, the higher the rate of ribbon should be cleaned with sandpaper
evaporation of water. to remove the oxidised parts.
4. Vinegar – Sour
– The faster the movement of air, the Neem – Bitter
higher the rate of evaporation of 5. An acid is a chemical that turns a blue
water. litmus paper red.
An alkali is a chemical that turns a red
– The wider the surface area litmus paper blue.
exposed, the higher the rate of (Any other answers are accepted)
evaporation of water.
Activity 6.2
(Choose any two answers) 1. Universal indicator can show the pH
(c) (i)
4. Colloid: (a) (c) (f) value of a substance. Litmus paper
Suspension: (b) (e) cannot show the pH value but it can
Solution: (d) (g) determine whether a substance is acidic
5. Alcohol or alkaline.
6. (a) N, K, M, L 2. The substance has a pH value of 7
(b) Alum – To coagulate suspended because the substance is neutral.

particles in water Activity 6.3
Slaked lime – To reduce the acidity of 1. Strong acid has low pH value.
2. (a) Hydrochloric acid
water (b) Sodium hydroxide solution
Chlorine - To kill the microorganisms (c) Ethanoic acid
(d) Ammonia
in water. (e) Salt water
(Choose any two answers) 3. The pH value is below 7 because acidic
(c) Alum is added to coagulate
gases emitted from the factory will
suspended particles in water. Slaked dissolve in rain water. Thus, the rain
lime is added to reduce the acidity of water will become acidic.
water.
(d) Suspended particles mix with the
water and the water becomes cloudy.
7. (a) Sample C
(b) Sample B and D
(c) Sample C

(d) Sample B, C and D

9

Formative Practice 6.1 blue litmus paper changes to
1. Bitter gourd juice, mineral water, orange red, solution M is acidic. If the
colour of red litmus paper does
juice, hydrochloric acid not change colour, solution M is
2. Acids and alkalis are corrosive acidic.
3. (a) Acidic (Any other answers are
(b) Red accepted)
4. Fresh milk, pineapple juice, vinegar 3. (a) Acidic: P and R
Alkaline: Q
Activity 6.5 (b) P, R
1. (Answer based on the student’s finding) – Tastes sour
2. Hydrochloric acid + Sodium hydroxide ➝ – pH value less than 7

Sodium chloride + Water Q
– Tastes bitter
Formative Practice 6.2 – pH value more than 7
1. (a) Acid + Alkali ➝ Salt + Water (c) i) P – Vinegar// Lime juice
(b) Sulphuric acid + Sodium hydroxide ➝ ii) Q – Shampoo// Soap// Detergent
(Any other answers are accepted)
Sodium sulphate + Water 4. (a) Jellyfish's sting venom is alkaline,
2. The reaction of bacteria and the food
therefore soap and toothpaste which
residue on the tooth produces acid that are alkaline cannot neutralise the
corrodes the tooth and causes dental venom, but will increase the pain
caries. Toothpaste which is alkaline can caused by the venom.
neutralise this acid and prevent dental (b) Apply pineapple juice/ vinegar/ acidic
caries. substance to neutralise the alkaline
3. Yes. Hair conditioner which is acidic can venom.
neutralise the residue of shampoo on hair
which is alkaline. This makes the hair HOTS Mastery 6
look soft and shiny. 5. (a) The fishy smell can be removed by

Summative Practice 6 cleaning the fish using lime juice or
1. (a) Formic acid, malic acid bilimbi fruit (belimbing buluh) which
(b) (i) Formic acid is acidic. The body of dead fish has
(ii) Malic acid tissues that produce ammonia which
(c) No changes is alkaline and has a fishy smell.
2. (a) Flow the ammonia gas into water. (b) Add a few drops of universal indicator
into the vinegar, then add sodium
Test the solution with a suitable hydroxide solution little by little until
indicator. Record the pH of the the colour of the solution changes
solution. to green. At this point, the vinegar is
(b) pH paper can determine the pH value neutralised.
of a substance tested. Litmus paper (Student can use other indicators
cannot determine the pH value of a and the change in the colour at the
substance tested. neutral point depends on the type of
(c) (i) Yes. Phenolphthalein remains indicator)
6. (a) The farmer’s soil is too acidic. This
colourless in acidic and neutral is proven when the soil dissolved in
conditions and turns pink in water and reacted with baking soda
alkaline condition.
(ii) Put red and blue litmus papers
into solution M. If the colour of

10

to release gas. 3. The brightness of the bulb increases
(b) Soil that is too acidic is infertile because the current in the circuit
increases.
because it lacks mineral salts required
for the growth of plants. Mineral salts 4. When the voltage increases, the current
become less in acidic soil because increases and the brightness of the bulb
they easily dissolve in rain water and increases.
are washed away to other places.
(c) Add slaked lime to the soil. Slaked Experiment 7.1
lime which is alkaline will reduce the A 1. When the length of the nichrome wire
acidity of the soil.
increases, the resistance increases.
Chapter 7 2. When the length of the nichrome wire

Activity 7.2 increases, the current flowing through
1. The pieces of shredded paper are the circuit decreases.
3. When the resistance increases, electric
attracted to the object because the object current decreases.
that has been rubbed with woollen cloth
will have electrostatic effect. B 1. When the number of dry cells increases,
2 i. Rub 2 balloons filled with air against the reading of the voltmeter increases.

dry hair. 2. When voltage increases, electric current
ii. After a few minutes, place the increases.

balloons close to each other. Formative Practice 7.1
iii. The balloons will repel each other.
iv. This shows that both balloons have 1. (i) Heat energy

collected the same charges when (ii) Kinetic energy
rubbed with the hair.
(iii) Elastic potential energy
Activity 7.3
1. Sparks are produced when the sphere is 2. The clouds and the air graze each other

brought closer to the dome. and cause positive charges to gather
2. The gold leaf diverges.
on the top part of the cloud and the
Activity 7.5
1. The pointer of the galvanometer deflects. negative charges gather on the lower

This shows that there is a flow of charges part of the cloud. The movement of
to the Earth.
2. Place the metal cap of an electroscope negative charges from the cloud to the
close to the dome of the Van de Graaff
generator. The divergence of the gold earth causes electricity discharge and
leaf shows the presence of charges.
3. Electric current is the rate of electric produces lightning.
charges flowing through a conductor.
3. R = 12 V
Activity 7.6 0.025 A
1. When the number of dry cells increase,
= 480 Ω
the current increases.
2. When the number of dry cells increase, The current produced is steady because

the voltage increases. it is supplied by voltage from the

accumulator.

Activity 7.7
1. The current that flows through every point

is the same.
2. The other bulb does not light up. When

one bulb is removed, the circuit is broken.

11

Activity 7.8 Activity 7.9
1. The voltages of bulb M and N are the 1. At both poles of the magnet.
2. From the north pole to the south pole.
same because the voltage in the parallel 3. The closer the magnetic field lines, the
circuit is the same.
2. The advantages of a parallel circuit stronger the magnetic field.
(a) Each device can be controlled by its
Activity 7.10
own switch. 1. Iron filings are used to show the magnetic
(b) The damage in one device does
field patterns and the compass is used to
not interrupt the function of another show the direction of the magnetic field.
device. 2. Straight wire, coiled wire and solenoid
The disadvantage of a parallel circuit produce different magnetic field patterns.
The voltage in each device cannot be 3. When the direction of the electric current
controlled. flow is reversed, the direction of the
magnetic field line is also reversed.
Formative Practice 7.2 However, the pattern of the magnetic field
remains the same.
1.

2. (a) R = 1 Ω + 3 Ω + 5 Ω Formative Practice 7.3
1. The area surrounding the magnet under
=9Ω
the influence of the magnetic force.
2. (a) The nail becomes an electromagnet

(b) P

(b) I = 9 V = 1 A
9 Ω

(c) 1 Ω Resistor

V = 1 A x 1 Ω

= 1 V

3 Ω Resistor Q
=1Ax3Ω
=3V (c) P – North, Q – South

5 Ω Resistor (d) The strength of the magnetic field

V = 1 A x 5 Ω increases

= 5 V 3. (a) True (b) True

3. (a) R = 2 Ω Summative Practice 7
1. (c)
(b) V = 4 V 2. (a) Imran will feel a mild electric shock

(c) Current in 3 Ω Resistor caused by the electricity discharged
from his body.
I = 4V (b) By wearing shoes with rubber soles.
3Ω 3. (a) The large amount of water vapour
formed in the air during damp
= 1.3 A weather prevents the gathering of
charges on an object.
Current in 6 Ω Resistor (b) The current from the Van de Graaff
generator is less compared to the
I = 4 V
6 Ω

= 0.67 A

12

domestic electric power supply. 2. Pushing force

4. (a) – Current (d) – Parallel

(b) – Conductor (e) – Resistor

(c) – Ohm

5. Parallel circuit. So, the alarm can be

switched on by a heat detecting switch

from any different locations in the same

building.

6. A1 = 2.4 A Point of application of force
A2 = 1.2 A
V1 = V2 = 12 V 3. (a) Action force and reaction force
(b)
HOTS Mastery 7
7. The copper coil is able to produce a Reaction
force
powerful electromagnetic effect. This
enables the removal of loads of scrap Action force
metals at a time.
Activity 8.4
Chapter 8 1. When buoyant force is equal to the

Activity 8.1 weight of the object, the object floats.
1. Activity A: Gravitational force When the buoyant force is less than
Activity B: Weight, normal force and the weight of the object, the object
submerges.
frictional force
Activity C: Elastic force Experiment 8.1
Activity D: Buoyant force 1. Copper, aluminium
2. Weight, normal force and frictional force 2. The block which is more dense than
3. Frictional force
water will submerge in water.
Activity 8.2
Activity 8.6
A 1. Force 2. newton (N) 2. Position X requires a bigger force.

3. Reading of the spring balance Position Y results in a bigger moment of
force.
increases because the number of
Experiment 8.2
weight increases. 1. The depth of dent produced is less when

B 1. Frictional force surface area increases.
2. Surface area increases, pressure
2. Reading of spring balance when
decreases.
wooden block is pulled on the surface 3. Depth of dent formed by metal block P

of the table is lower compared to when is larger than Q because metal block P
exerts a higher pressure.
the wooden block is pulled on the 4. The operational definition of pressure
is the depth of dent produced when two
surface of sandpaper. Frictional force metal blocks of different surface areas
drop on the plasticine.
causes the difference in the readings.
13
Formative Practice 8.1
1. (a) Gravitational force
(b) Frictional force
(c) Buoyant force

Activity 8.8 5.
This is because the atmospheric pressure
acting on the card is strong enough to support Atmospheric
the weight of the water in the glass. pressure

Activity 8.9 6.
A When volume of air in the syringe

decreases, air pressure increases.
B When temperature increases, air

pressure increases.

Activity 8.10 Pull
1. Push

Atmospheric
pressure

2. Seal Atmospheric Atmospheric
Vacuum pressure pressure
Pull
Pull Activity 8.11
3. 1. Size of air bubbles at the bottom of the
Seal
basin is smaller than the size of air bubbles
Atmospheric pressure Rubber tube nearer to the water surface.
Level of 2. Volume of air bubbles decreases as the
4. Atmospheric pressure water surface depth of water increases.
3. Pressure in liquid increases as the depth
Water End of the of liquid increases.
tube
Formative Practice 8.2
1. 20 N
2. (a) Surface C
(b) Pressure A = 0.03 N cm–2/ 333 N m–2
Pressure B = 0.0167 N cm–2/ 166.7 N m–2
Pressure C = 0.1 N cm–2/ 1 000 N m–2
3. (a) The density of helium gas in the

balloon is less than density of air
(b) The size of the balloon increases

because air pressure decreases

14

(c) 2. Fill the tube with water until full.

Flow of
water

B

Buoyant force Wooden
block
Weight
A
Summative Practice 8
1. (a) Elastic force HOTS Mastery 8
(b) Gravitational force 11. Nurul should sit further from the fulcrum,
2. Measuring device: Spring balance
S.I. unit: newton (N) so that the moment of force increases to
balance the moment of force by Wan.
12. Modification: Use a wheel with a bigger
surface area.
Explanation: Pressure reduces when the
surface area increases.

Action Reaction Chapter 9
force force
Formative Practice 9.1
1. joule, J
2. No, sense of touch is not a reliable
4. Inhaling air into lungs and drinking water
method to be used because the
from a straw temperature cannot be observed in this
manner.
5. 0.75 N m 3. (a)

6. (a) 2 500 N m–2 Activity 9.1
1. Thumbtack K on the copper rod falls off
Total pressure by car
first because it is the closest to the heat
= 1 000 = 2 500 N m–2 source.
4(0.1) 2.

(b) Pressure exerted by each tyre

= 2 500 = 625 N m–2
4

7. (a) 5 N

(b) 5 N

(c) Weight of stone is greater than the

upthrust force.

8. Close the hole with her finger to prevent

atmospheric pressure from entering the

straw so that water will rise when sucked.

9. Shoe Q because it has bigger surface 3. The convection current can be seen
clearly.
area which will decrease the pressure
4. Place a thermometer to the surface of
exerted on the field. The shoe will not the bell jar.

sink into the soft ground. .
Experiment 9.1
10. The tube is not filled with water and the 1. The temperature of water decreases

end of tube in beaker A is higher than in the most in flat-bottom flask N because

beaker B. 15

Modification:

1. Make the position of beaker B higher.

aluminium is not a good heat insulator objects absorb heat faster than white
and transfers heat from the water faster. objects.
2. Flat-bottom flask K is used as a control B 1. Can K
to be compared with the result of the 2. The temperature in can K decreases
experiment. more after 10 minutes because dark
objects radiate heat faster than white
Formative Practice 9.2 objects.
1. The heating of water begins around 3. Radiation
4. (Student's answer)
the coil of the heater. Hot water
moves upwards and cold water moves Formative Practice 9.4
downwards. This convection process 1. Bright colours are poor heat absorbers,
enables the water to be heated faster.
2. The aluminium foil is a good heat therefore we feel cooler.
conductor that can hasten the process of 2. The shiny inner surface enables heat
cooking the chicken.
3. A polystyrene container is a heat insulator from the hot water to be reflected again
that prevents heat from the surroundings inside and the temperature of the hot
reaching the ice cubes. So, the process water is maintained.
of melting of the ice cubes can be slowed 3. Heat absorber: The cooling agent of the
down. car engine and ice pack
4. The blanket functions as a heat insulator. Heat radiator: Candles and pots
The heat from the body is trapped in (Any other answers are accepted)
the blanket and it controls the body
temperature so that it is not too cold. Summative Practice 9
1. (a) The windscreen of the car cracked
Activity 9.4
1. The metal bar that has been heated because a sudden change in the
temperature causes a non-uniform
cannot be inserted into the gauge contraction of the layer of the
because the metal bar has expanded. windscreen.
2. Coloured water is used so that the (b) Wind down the windows of the car
change in the water level is easily visible. before turning on the air conditioner
3. Expansion and contraction of air inside to allow the hot air from inside the car
the balloon cause the size of the balloon to escape first.
to change. 2. High heat caused by hot weather or
burning of rubbish would increase the
Formative Practice 9.3 pressure inside the can and cause it to
1. The volume of water increases. explode.
2. The cable contracts when it is cold, so it 3. Switch on a bulb inside a vacuum flask.
After a few minutes the flask will become
will not cause any damages. hot. This proves that heat can transfer
3. Yes. Expansion and contraction can without a medium through radiation.
4. (a) The convection current is caused
damage the structure of buildings and by the change in the density of fluid
cause the walls to crack. particles. The hot fluid particles will
expand, become lighter, then rise.
Experiment 9.2 Whereas, the cold fluid particles
A 1. Can K become more dense and move
2. The temperature in can K increases downwards. The continuous flow of
this fluid causes convection.
more after 10 minutes because dark

16

(b) Radiation is the fastest heat transfer Activity 10.4
method because it does not need any 1. Pitch of sound increases.
medium for propagation. 2. The nearer the distance between sound

HOTS Mastery 9 source and observer, the higher the
5. Dayah can use two thin blankets sewn frequency of sound.
3. No, because there is no relative
together to solve this problem. Two thin movement from the person who carries
blankets sewn together trap heat between the sound source and the sound source.
them. Air, which is a heat insulator (poor
conductor of heat), prevents body heat Formative Practice 10.2
from escaping to its surroundings. 1. The voice box of women produces sound
(Any other answers are accepted)
6. • Open the lid of the polystyrene for the with higher frequency compared to the
voice box of men. So, women’s voice has
heat to be released to its surroundings a higher pitch.
through the surface of water. 2. (a)
• Place the beaker in a container with ice 3. (a)
for the heat to be released quickly.
Formative Practice 10.3
Chapter 10 1. Yes, distance of source that is far from

Activity 10.1 the surface causes sound to lose energy,
A 1. Sound is not heard because there is no resulting in a weaker echo.
2. The rough walls of a cave causes
medium for sound to propagate. reflection of sound in all directions. This
2. Air, water and flour causes echo to be heard repeatedly.
B 1. (a) Towel 3. (i) To examine condition of foetus in the
(b) Metal sheet
2. Glass is a good reflector of sound. womb.
(ii) To estimate depth of sea.
Formative Practice 10.1
1. Vibration of insect wings, vibration of Summative Practice 10

plucked guitar strings, vibration of air in 1. Use two polystyrene cups connected with
a trumpet and a pipe, vibration of a voice
box. a string.
(Any other answers are accepted)
2. (c) – The polystyrene cups trap sound
3. They absorb and prevent reflection of
sound. waves.

Activity 10.2 – The string will help to transfer the
1. (a) Loudness increases when amplitude
sound waves.
increases.
(b) Pitch of sound increases when 2. (a) (b)

frequency increases. 3. Sound will propagate faster in air of
2. When amplitude increases, size of higher temperature because transfer of
sound energy can occur faster due to the
vibration of wave also increases. A louder higher kinetic energy of air molecules.
sound is produced.
3. A louder and higher pitch of sound is 4. (a) Sound is reflected by a hard surface,
produced. such as the wall.

(b) Furniture will absorb some sounds

17

and reduce the effect of reflection. Chapter 11
5. (a) – Ultrasound waves are transmitted
Formative Practice 11.1
by a scanner probe that is moved 1. A galaxy is a set of bodies that are made
across the belly of a pregnant
mother. up of millions of stars together with gas
– The ultrasound waves are and dust.
reflected when it hits the foetus in 2. The birth of a star is believed to
the womb. have happened through the Nebular
– Information from the reflection Hypothesis:
will be shown as an image on the i. The nebula cloud that contains gas
monitor screen.
(b) Advantages of ultrasound: and dust begins to compress due to
– Not harmful to the foetus in the the gravity action on it.
womb. ii. Stronger gravity causes the gas and
– Can be done more often or dust to be compressed in the center
repeatedly. and start to rotate.
– Painless iii. As time passes, this object becomes
– Does not use radiation bigger, more compact and its gravity
– Results can be obtained increases. Its rotation also becomes
immediately faster.
(c) – To determine the depth of sea. iv. The nebula begins to shrink and form
– To locate schools of fish in the sea. a hot and high density core.
– To detect cracks inside engines v. This hot core releases its heat
– To clean jewellery and light as a result of the nuclear
(Any other answers are accepted) reaction, and then it forms a star.
6. (a) Pitch of sound increases because 3. (a) The Earth’s temperature will become
tighter guitar string produces higher very low because there is no heat
frequency of vibration. from the Sun.
(b) Strength of sound increases because (b) There will be no day and night
amplitude of vibration increases. phenomenon because the Earth has
no source of light.
HOTS Mastery 10 (c) Living things on Earth will die due to
7. – Install layers of sound absorber from extremely low temperature.
4. Size, colour, temperature, brightness and
soft material to reduce reflection of distance from Earth.
loud sound. 5. The temperature of a star is determined
– Layer of sound absorber from through observation of the colour of the
materials such as sponge, cushion star as seen from Earth using a telescope
and softwood to reduce the effect of
reflection of sound waves. Summative Practice 11
(Any other answers are accepted) 1. (a) A star
8. Use high frequency signals such as (b) 6 000 K to 7 500 K
lasers that operate at frequency of light. (c) When the temperature and pressure
Data in digital form will be changed
to analogue and can be detected by at the core become too high, a
receiver through transmission of laser nuclear reaction will take place.
light. Hydrogen gas is converted into
helium. A lot of heat and light energy
18 will be released.

2. (a) Yes, the Sun emits its own light. Saturn 1.43 × 109 9.5 1.51 × 10–4
(b) This is because the Sun is the closest Uranus 2.87 × 109 19.1 3.02 × 10–4
Neptune 4.5 × 109 30 4.74 × 10–4
star to Earth.
3. In my opinion, the mission would not be Formative Practice 12.1
1. A.U. and ly are used because the
successful because the diameter of a
galaxy such as the Milky Way can reach distance of the planets in the solar system
up to hundreds of light years. In addition, is too great and can reach up to millions
the distance between the Milky Way of kilometres. Therefore, relative units
galaxy and the Andromeda galaxy can such as A.U. and ly are used so that the
also reach up to thousands of light years. numbers in the calculation of distance
Therefore, taking into consideration the between planets would not be too big.
factor of human age that can only reach 2. Mercury
approximately 100 years, an astronaut 3. The further the distance between a
would not be able to stay alive and make planet and the Sun, the lower its surface
it to the Andromeda Galaxy. temperature.
(Any other answers are accepted)
Summative Practice 12
HOTS Mastery 11
4. (i) The spaceship has to be designed 1. (a) Eight planets

using materials that can reflect heat (b) The planet that is closest to the Sun is
and withstand heat of more than
10 000 K. Mercury and the planet that is furthest
(ii) This material needs to reflect heat
because the temperature in the from the Sun is Neptune.
spaceship cannot get too high as
the human body is not be able to (c) Mercury is the closest planet to the
withstand high temperatures.
(iii) Other than that, this vehicle needs Sun. The closer the planet is to the
to be a high speed vehicle because
factors such as human age and long Sun, the faster the planet orbits the
distance will not enable the astronauts
to make it to the Sun. Sun.

2. (a) The Earth rotates from west to east.

(b) On Venus, the Sun rises in the west

and sets in the east.

(c) If the Earth stops rotating,

– longer days occur on the surface

that faces the Sun while longer

Chapter 12 nights occur on the surface that is

away from the Sun.

Activity 12.1 – the area of the Earth that faces the

Table 12.1 Sun will experience dry seasons.

Distance Distance Distance 3. (a) Distance = 4.37 ly

Planets from Sun from Sun from Sun Distance in km

(km) (A.U.) (ly) = Distance in ly × 9.5 × 1012 km

Mercury 5.79 × 107 0.39 6.09 × 10–6 = 4.37 × 9.5 × 1012

Venus 1.08 × 108 0.72 1.14 × 10–5 = 4.15 × 1013 km

Earth 1.50 × 108 1.0 1.58 × 10–5 (b) Distance = 4.15 × 1013 km
4.15 × 1013 km
Mars 2.28 × 108 1.52 2.4 × 10–5 Distance in A.U. = 1.5 × 108 km

Jupiter 7.78 × 108 5.19 8.19 × 10–5 = 2.76 × 105 A.U.

19

4. (Student’s answer. All products may be 3. When the path of a comet is close to the
accepted if it uses recyclable materials). Sun, the high temperature of the Sun
will cause part of the ice structure of the
5. (a) The hottest planet is planet P, the comet to change into gas, which shapes
coldest planet is planet Q. This is the tail of the comet. Due to the fact
because planet P is the closest to the that the area with gas has a lower mass
Sun while planet Q is the furthest from than the head portion, the tail portion will
the Sun. always be away from the Sun because of
the effect of the gravity of the Sun on the
(b) Planet Q. The further a planet is from comet.
the Sun, the more time it needs to
travel around the Sun in one orbit. Summative Practice 13

HOTS Mastery 12 1. (a) Kuiper (d) Jupiter
6. (a) Venus does not have enough water
(b) Meteoroid (e) Amor
and oxygen necessary for living things
(refer to table 12.2). (c) Comet (f) Asteroid
(b) The statement made by Pei Lui is
correct. Venus is the hottest planet 2. Meteorite. A meteorite is a rock that hits
in the solar system. This is because
Venus has a high carbon dioxide the surface of the Earth. A meteor would
content in its atmosphere. This
causes the reflected heat to be not reach the Earth as it would have
trapped in the atmosphere, therefore
it increases the surface temperature burned out before it reaches the Earth.
of the planet.
7. Europa has a possibility of having living 3. Meteor. A meteor shower happens when
things because it has seawater which is
needed for living things. many meteors enter the Earth at the

Chapter 13 same time.

Formative Practice 13.1 4. (a) If a large asteroid less than 10 km
1. When a meteoroid moves close to the
in size enters the atmosphere, the
Earth, it will enter the atmosphere of the
Earth due to the gravity of the Earth. species at the area of impact and
When a meteoroid enters the atmosphere
of the Earth and burns, it will be known about 100 kilometres around the area
as a meteor. If the meteor does not stop
burning in the atmosphere, and reaches will be destroyed. However, if the
the Earth as rock fragments, the meteor
will then be known as a meteorite. asteroid is 10 km or bigger in size, the
2. Collisions between an asteroid and
the Earth happen because the path entire species on the Earth will face
of the asteroid path intersects with or
is very close to the orbit of the Earth. extinction (as what happened to the
If an asteroid and the Earth are at the
intersection point at the same time, a dinosaurs.).
collision might happen.
(b) (i) It can be avoided by changing the
20
course of the asteroid or breaking

it into smaller rock fragments.

(ii) A spaceship can be used to

attach explosives to the asteroid

or shoot it with bombs that have

strong explosive powers before it

reaches Earth.

(c) (i) The asteroid impact 65 million

years ago destroyed living

things and caused a change in

temperature. The temperature

in one area reduced drastically

while the temperature in another

area increased drastically,

causing the death of dinosaurs.

(ii) This opinion is acceptable. This the Earth, their size and speed reduce
is because each scientists have due to the friction with the atmosphere.
their own opinion and theory Therefore, the effects of collision will be
about events that happened worse in space as compared to the Earth.
millions of years ago.
If there are any signs or HOTS Mastery 13
evidence, a theory can be 7. In my opinion, the collision can happen
debated and scientists can study
it again. after they pass Mars and before they
reach Jupiter. This is because there is an
5. Yes, it can. This is because some asteroid belt in the area which can cause
asteroids have their own gravity while collision.
some don’t. For an asteroid that has its 8. Yes. This is because if there is a collision
own gravity, its mass has the ability to with a large object, the rotation of the
continue expanding and attracting other Earth on its axis can change. When the
asteroids nearby to combine. When the speed of rotation is affected, the gravity
asteroid becomes too large, this asteroid of the Sun and other planets will influence
can become a planet. the Earth and pull the Earth towards it.
This phenomenon can cause the Earth to
6. Meteors in space are larger in size and slip from its orbit.
have higher speeds. When they reach

21