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ISBN: 978-629-7557-47-2
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Format: 190mm X 260mm TPTV Focus 2023 Sc BI version F2_pgi CRC
Science FORM
Dual Language Programme 2 KSSM
• Fauziah Mo’men
• Jariah Khalib
(Textbook Author)
• Maznah Omar
(Textbook Author)
• Badariah Hamzah
(Textbook Author)
• Shamsulikram Abdul Hamid
(Textbook Author)
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CONTENTS
Maintenance and Continuity of Exploration of Elements in
Theme 1 Theme 2
Life Nature
Chapter Chapter
1 Biodiversity 1 5 Water and Solution 59
Concept Map 1 Concept Map 59
1.1 Diversity of Organisms 2 5.1 Physical Characteristics of Water 60
1.2 Classification of Organisms 5 5.2 Solution and Rate of Solubility 68
Summative Practice 1 12 5.3 Water Purification and Water Supply 72
Summative Practice 5 75
Chapter
2 Ecosystem 14 Chapter
6 Acid and Alkali 77
Concept Map 14
2.1 Energy Flow in Ecosystem 15 Concept Map 77
2.2 Nutrient Cycle in Ecosystem 17 6.1 Properties of Acids and Alkalis 78
2.3 Interdependence and Interaction Among 6.2 Neutralisation 86
Organisms and between Organisms and
Summative Practice 6 89
the Environment 19
2.4 Role of Human in Maintaining a Balanced
Nature 27
Summative Practice 2 28
Theme 3 Energy and Sustainability of Life
Chapter Chapter
3 Nutrition 30 7 Electricity and Magnetism 90
Concept Map 30 Concept Map 90
3.1 Classes of Food 31 7.1 Electricity 91
3.2 Importance of a Balanced Diet 36 7.2 Flow of Electric Current in a Series Circuit
3.3 Human Digestive System 39 and Parallel Circuit 100
3.4 Process of Absorption and Transportation 7.3 Magnetism 105
of Digested Food and Defecation 43 Summative Practice 7 111
Summative Practice 3 46
Chapter
Chapter
4 Human Health 48 8 Force and Motion 113
Concept Map 48 Concept Map 113
4.1 Infectious and Non-infectious Diseases 49 8.1 Force 114
4.2 Body Defence 52 8.2 Effects of Force 117
Summative Practice 4 57 Summative Practice 8 128
ii
00 Contents Foc PT3 Scicence.indd 2 16/03/2023 5:33 PM
Chapter Chapter
9 Heat 130 12 Solar System 169
Concept Map 130 Concept Map 169
9.1 Relationship between Temperature and 12.1 Solar System 170
Heat 131 Summative Practice 12 179
9.2 Heat Flow and Thermal Equilibrium 133
9.3 Principle of Expansion and Contraction of
Matter 139
Chapter
9.4 Relationship between Types of Surface of 13 Meteoroid, Asteroid, Comet 180
Object, and Heat Absorption and Emission 144
Summative Practice 9 148 Concept Map 180
13.1 Other Objects in the Solar System, such
as Meteoroids, Asteroids and Comets 181
Chapter Summative Practice 13 186
10 Sound Waves 150
ANSWERS 187
Concept Map 150
10.1 Characteristics of Sound Waves 151
10.2 Loudness and Pitch of Sound 155
10.3 Phenomenon and Applications of Reflection
of Sound Waves 158 UPSA Model Paper https://qr.pelangibooks.
com/?u=okyoLO7n
Summative Practice 10 160
Theme 4 Earth and Space Exploration https://qr.pelangibooks.
UASA Model Paper com/?u=0MyO4fvh
Chapter Stars and Galaxies in the
11 Universe 161
Concept Map 161
11.1 Star and Galaxies in the Universe 162
Summative Practice 11 167
iii
00 Contents Foc PT3 Scicence.indd 3 16/03/2023 5:33 PM
Theme 1: Maintenance and Continuity of Life
Chapter
3 Nutrition
CONCEPT MAP
Diet that contains seven classes of
food in correct quantities to meet the
Carbohydrates needs of the body.
Protein
Balanced diet
Protein
Fat
Protein
Factors:
Protein
V Proteinitamins • Climate
• Age
Food • Gender
Protein
Fibre
Protein classes • Occupation
• Body size
• Health condition
Minerals
Nutrition Absorption, transportation of
Water digested food and defecation.
Small intestine
Food digestion
Digested food Undigested food
Physical digestion Chemical Transported go to Minerals
Breakdown of large digestion by and vitamin
food particles into Breakdown of
smaller particles complex molecules Blood vessels Large intestine
with the help of into simpler
teeth and tongue molecules with the to Store in
help of enzymes
Rectum
Body cells
Eliminate
through
Anus
Access to
INFOGRAPHIC
30
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Science Form 2 Chapter 3 Nutrition
3.1 Classes of Food Protein
1. We need food because food provides
substances needed by our bodies. Besides
that, food is also necessary to:
(a) provide energy,
(b) provide substances to repair tissues
and build new cells,
(c) maintain good health.
2. The diagrams below show the classes of CHAPTER
food.
Protein are organic compounds made up
Carbohydrate of carbon, hydrogen, oxygen and nitrogen 3
elements.
1. Some proteins contain sulphur and
phosporus elements.
2. Proteins are digested into their basic units
which are amino acids.
3. Animal proteins have all the essential
amino acids whereas plant proteins only
have some of the essential amino acids.
• Essential amino acids – amino acids
obtained from food sources
• Non-essential amino acids – amino acids
synthesised by the body
4. Proteins funtion to:
Carbohydrates are organic compounds (a) provide energy for us,
that contain elements of carbon, hydrogen
and oxygen. (b) growth,
(c) help repair damaged cells,
1. There are three types of carbohydrates (d) replace dead cells,
which are: (e) produce enzymes, hormones and
(a) Starch: Food stored in plants. antibodies.
(b) Glycogen: Food stored in animals’ 5. Excess proteins (amino acids) cannot
muscles and liver. be kept in the body. Amino acids will be
(c) Cellulose: Form plant cells. changed to urea and eliminated through
2. Glucose is the basic unit of carbohydrates. the process of urination and perspiration.
Glucose molecules form starch, glycogen Fat
and cellulose.
3. Carbohydrates are the staple food of
humans.
4. Function of carbohydrates is to provide
energy to carry out body processes.
31
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Science Form 2 Chapter 3 Nutrition
Fats are organic compounds that are
made up of carbon, hydrogen and oxygen
elements.
1. Fat molecules consist of glycerol and fatty
acids with the ratio of 1 : 3.
2. There are two types of fats which are plant Vitamins are organic compounds that do
fats and animal fats. not provide energy.
3. Oil is a fat that exists in liquid form at room
temperature. 1. Vitamin are needed to maintain health and
prevent infection of diseases.
4. Fats provide a lot more energy compared to
CHAPTER
carbohydrates and proteins. 2. Vitamins can be classified into two
3
groups:
5. Fats also function to:
(a) control body temperature, Vitamin
(b) protect internal organs such as the
heart,
(c) transport vitamins A, D, E and K.
6. When we consume a lot of fatty foods, Water-soluble Fat-soluble
excess fat will be stored in the adipose vitamins vitamins
tissue under the skin and it acts as a thermal B and C A, D, E and K
insulator.
Figure 3.1 Types of vitamins
Vitamin
Table 3.1 Types, sources, importance and effects of vitamin deficiency
Effects of
Vitamins Sources Importance
deficiency
A Milk, egg yolk, fish • For night vision • Night blindness
oil, tomatoes, green • Maintain healthy skin • Skin disease
vegetables
B Yeast, liver, eggs, green • Maintain nervous system functions • Beri-beri
vegetables • Formation of red blood cells • Anaemia
C Fruits, vegetables • Fight infection of diseases • Scurvy
• Maintain gums and mouth health
D Butter, eggs, fish oil, green • Help in calcium absorption • Rickets
vegetables, or exposure to • Strengthen tooth enamel • Toothache
sunlight • Maintain healthy skin • Osteomalacia
(softening of
bones)
32
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Science Form 2 Chapter 3 Nutrition
E Cereal, green vegetables, • Maintain reproductive system functions • Infertility
wheat • Maintain position of foetus in the womb • Hair loss
• Help production of cell membrane
• Maintain nerves and muscle health
K Milk, egg yolk, fish oil, • Speed up the process of blood clot • Prolonged
tomatoes, green vegetables bleeding
Fibre Mineral
CHAPTER
3
Fibre is a substance that cannot be
decomposed by the digestive system.
1. Fibre is made up of plants which have Minerals are inorganic food needed by
cellulose in their cell walls. the body.
2. Some examples of food rich in fibre are
fruits, vegetables and cereal. 1. Minerals do not provide energy but are still
3. Fibre: required in small amounts.
(a) stimulates peristalsis and prevents 2. Minerals are required by the body to build
constipation, new cells and regulate bodily processes.
(b) absorbs water in the intestine and 3. The table below shows the variety of mineral
helps remove waste quickly, sources, their importance and effects of
(c) reduces blood cholestrol level and deficiency.
controls sugar in the blood.
Table 3.2 Types, sources, importance and effects of mineral deficiency
Mineral Source Importance Effect of deficiency
Calcium Milk, anchovies, prawns, • Helps with blood clotting • Rickets
green vegetables • Strengthens bones and teeth • Osteoporosis
Sodium Salt, meat, eggs, cheese • Maintains nerve function • Muscle cramps
Iron Liver, meat, eggs, green • Maintains nerve function • Anaemia
vegetables
Iodine Seafood, fruits • Helps with function of thyroid glands • Goitre
Phosphorus Cheese, meat, eggs, • Strengthens bones and teeth • Rickets
vegetables, milk • Forms nucleic acid in the DNA • Brittle teeth
Potassium Plants and animals • Helps with muscle contraction • Immobility
• Maintains nerve function • Muscle cramps
33
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Science Form 2 Chapter 3 Nutrition
3. Our body needs water to:
Water
(a) eliminate waste substances like urea,
(b) control blood concentration,
Water is a very important compound for (c) control body temperature,
the body. (d) transport digested food to the body
cells.
1. Water is made up of hydrogen and oxygen 4. We receive water not only from drinks but
elements. also from various sources such as fruits and
vegetables.
2. About 65 – 70% of our body mass consists
of water. Water is in our blood, cytoplasm,
organs and in between body cells. Food groups
and nutrition
CHAPTER
VIDEO
3
Experiment 3.1
Aim: To determine the presence of starch, glucose, protein and fat in food samples.
Materials and apparatus: Iodine solution, 1% starch suspension, Benedict’s solution, 10% glucose solution,
Millon’s reagent, albumen suspension, ethanol, cooking oil, distilled water, cork stopper, test tube, dropper,
beaker, Bunse burner, wire gauze, tripod stand and tongs.
Procedure:
A Iodine test for starch
Iodine solution
1. 2 ml of starch suspension is poured into a test tube.
2. Two drops of iodine solution is put into a test tube as in Figure 2 ml of 1%
3.2. starch suspension
3. The observation is recorded. Figure 3.2 The set-up of apparatus
B Benedict’s test for glucose
1. 2 ml of glucose solution is put into a test tube. Water bath Glucose solution
+
2. 2 ml of Benedict’s solution is added to the test tube and shaken. Wire Benedict’s solution
gauze
3. The mixture is boiled in a water bath for 5 minutes. Tripod stand Bunsen burner
4. The observation is recorded.
Figure 3.3 The set-up of apparatus
C Millon’s test for protein
1. 2 ml of albumen suspension is poured into a test tube. Water
Millon’s Albumen
+
2. 2 drops of Millon’s reagent is added to the test tube and reagent bath Millon’s
shaken. Wire reagent
gauze
Albumen
3. The mixture is boiled in a water bath for 5 minutes. suspension Bunsen
burner
4. The observation is recorded.
Figure 3.4 The set-up of apparatus
34
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Science Form 2 Chapter 3 Nutrition
D Emulsion test for fat
1. 3 ml of ethanol is poured into a test tube.
2. Two drops of cooking oil is added into the test tube. The test tube is covered with a cork stopper and
shaken.
3. The test tube is left for 2 to 3 minutes. Cooking Ethanol
oil +
4. Four drops of the mixture is dripped into another test tube Cooking
filled with 20 ml of distilled water. oil
5. The test tube is covered with a cork stopper and shaken. It is Ethanol Distilled
water
left for 2 to 3 minutes.
6. The observation was recorded. Figure 3.5 The set-up of apparatus CHAPTER
Observation:
Activity Observation Inference 3
A Solution turned dark blue Presence of starch
B Brick red precipitate formed Presence of glucose
C Brick red precipitate formed Presence of protein
D White emulsion formed Presence of fat
Conclusion:
1. Solution turned dark blue in activity A, showing the presence of starch.
2. A brick red precipitate formed in activity B, showing the presence of glucose.
3. Brick red precipitate formed in activity C, showing the presence of protein
4. A white emulsion formed in activity D, showing the presence of fat.
Formative Practice 3.1
1. Each food class has specific functions. The figure below shows some examples of food for different classes.
State the food class and its function.
Example of food Food class Function
(a)
(b)
(c)
2. Faridah often has bleeding gums when she brushes her teeth.
(a) In your opinion, what is the possible problem faced by Faridah?
(b) State the healthcare related to nutrition that can be practised to prevent the problem.
35
03 Focus KSSM SC F2.indd 35 16/03/2023 5:43 PM
Science Form 2 Chapter 3 Nutrition
3. Our food intake needs to be varied
3.2 Importance of a Balanced Diet because there is no one type of food that
can provide all the necessary nutrients to
A balanced diet is a diet that contains all the body.
the food classes needed by the body in
right quantities to meet the needs of the 6-8 glasses Limit intake of fats, oils,
body. of sugars and salts
plain water
every day Source of protein:
1. A balanced diet is necessary to: 1-2 servings
(a) provide energy, Carbohydrates:
(b) provide substances for growth, 3-5 servings
(c) provide nutrients to maintain health. Fruits: Vegetables:
2 servings ≥ 3 servings
CHAPTER
2. Food intake should be based on the food
3
pyramid which is a chart to help us plan Figure 3.6 Food pyramid
our type of food intake with the suitable
amount.
Age Occupation
Growing children and teenagers need People who do heavy work like farmers,
more carbohydrates to provide energy construction workers and cleaners need
and protein for growth. They are usually more energy. Therefore, their dietary
more active than adults. needs are higher compared to those who
work in the office.
Body size
Gender
People with bigger bodies
Men usually do heavier Factors that
work and carry out more affect a balanced need to eat more as they need
active activities compared to diet more energy for their activities
as compared to smaller sized
women. Therefore, they need people.
more food to supply more
energy compared to women.
Climate
Health condition
People who live in cold countries release
People with sicknesses need more nutritious more heat to the environment. Therefore,
food. This is because they need more energy to they need to take more fats in their diets
heal. to maintain their body temperature.
Figure 3.7 Factors that affect a balanced diet
36
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Science Form 2 Chapter 3 Nutrition
Calorific Value of Food Calorific value for this meal
= 445 + 2(30) + 250
Calorific value is the total amount of = 755 kcal
energy released when 1 gram of food is
completely burned. 5. Figure 3.8 shows the nutrition information
on a food label that lists the amount of
energy in protein, fat, carbohydrates and
1. This amount of energy is measured in the
unit of calorie (cal) or Joule (J). other ingredients in the food.
1 cal = 4.2 J Nutrition Information
Per 56 g bar Per 100 g
Energy kCal 260 464 CHAPTER
1 kilocalorie (kcal) = 4.2 kilojoule (kJ)
kJ 1,089 1,944
Protein g 10.05 17.95
2. One calorie is the total amount of heat Carbohydrates g 28.72 51.29 3
needed to raise the temperature of one Sugars g 8.62 15.39
gram of water by 1°C. Total Fat g 11.39 20.34
3. Only three classes of food provide energy Saturated Fat g 1.44 2.57
to us. They are carbohydrates, protein Trans Fat mg 0 0
and fat. The amount of energy provided is Fiber g 7.18 12.82
different. Sodium mg 71.8 128.2
Figure 3.8 Nutrition information on food label
Table 3.3 Energy value for carbohydrates, protein
and fat
Planning a Balanced Diet
Calorific value 1. Before planning a balanced diet, factors
Food class like age, gender, occupation, body size and
(kJ/g) (kcal/g)
health condition need to be taken into
Fat 37 9 consideration first.
2. Balanced diet planning is very important to
Protein 17 4 ensure we gain sufficient nutrients so that
Carbohydrate 17 4 we are always healthy and do not feel tired
easily.
3. Table 3.5 shows the daily energy needs
4. The food calorific value in a meal can be suggested for certain groups of people.
estimated if we know the calorific value of
each ingredient in that particular food. For Table 3.5 Suggestion of daily energy needs for
example, the following breakfast menu: certain group of people
Table 3.4 Energy value for certain types of food Group Gender Energy
needs (kJ)
Calorific
Menu Quantity
value (kcal) Male 8 500
Children
Fried mee 1 plate 445 Female 8 500
Watermelon 2 slices 30 Male 12 500
Teenagers
Milo 1 glass 250 Female 9 500
37
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Science Form 2 Chapter 3 Nutrition
Male 11 500 The Importance of Maintaining
Health
Male (Active) 20 000
Female 9 500 1. Health is the most valuable treasure to
Adults Female (Active) 12 500 a person. To remain healthy, we should
consume nutritious food.
Pregnant mother 11 500
2. The main cause of illnesses which are
Breastfeeding 11 500 difficult to cure is due to not having a
mother
complete meal and lack of nutritious food
Male 8 500 as well as lack of exercise.
Seniors
Female 6 500
3. Besides that, having an unbalanced meal
could also cause malnutrition and health
CHAPTER
4. Table 3.6 shows a diet plan for a boy who problems.
3
needs 8 500 kJ.
4. Therefore, we should practise a healthy
lifestyle and a balanced diet such as:
Table 3.6 Energy value for different type of food
(a) Eating food with less sugar, salt and fat.
Food Energy (kJ) (b) Regular exercise.
(c) No smoking and alcohol consumption.
Nasi lemak 1 634
(d) Regular check ups.
Breakfast Low fat milk 550
Guava 290
INFO
Rice 1 512 SCIENCE INFO
Fried chicken 1 071
Malnutrition happens when a person consumes
Mixed vegetables 440 unbalanced meals like excessive carbohydrates
Lunch
Ice cream 500 or less protein intake in their daily diet for a long
period of time.
Orange juice 205
Watermelon 252
Fried rice 1 050
Egg 500 Formative Practice 3.2
Dinner
Orange juice 202
1. What is the meaning of a balanced diet?
Watermelon 252
2. Compare the energy needs of a pregnant
Total amount of energy in a day 8 458 woman and a non-pregnant woman.
3. Amir is a football player whereas Aizat is an
accountant. In your opinion, who needs more
HOTS Challenge 1 food? Justify.
4. State what we should practise to maintain our
Dato’ Lee Chong Wei is a world known badminton health.
player. He always practises having a healthy and
nutritious balanced diet. Among some of his lunch
meals are a plate of rice, vegetables, chicken soup
as well as fruits. Give reasons why this menu is
prepared for him.
38
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Science Form 2 Chapter 3 Nutrition
3.3 Human Digestive System
Food digestion is a process of breaking down food from big and complex particles into small,
simple and soluble molecules so that they can be absorbed into the body cells.
1. There are two types of digestion which are Table 3.7 Comparison between physical digestion and
physical digestion and chemical digestion. chemical digestion
This process involved organs along the Physical digestion Chemical digestion
entire digestive tract. CHAPTER
Similarity
Digestion Breakdown of food happens in the digestive tract 3
Differences
Mouth,
Physical Chemical Organs stomach,
Mouth involved duodenum and
Breaking down Breaking down intestine
of food into tiny food from
pieces. This complex Complex Digestive Simple
process happens molecules to molecules outcome molecules
in the mouth with simpler
the help of the molecules No Involves Yes
teeth, tongue with the help of enzymes
and saliva. enzymes.
3. Other than that, there are other organs
Figure 3.9 Types of digestion
involved in the digestion process. They are
2. There are some organs along the digestive the pancreas, liver and gall bladder.
tract which are mouth, oesophagus, 4. Figure 3.10 shows the human digestive
stomach, duodenum, small intestine, large system.
intestine, rectum and anus.
Mouth
Structure of
human digestive
Oesophagus
system
3D MODEL
Liver
Gall bladder Stomach
Duodenum Pancreas
Small intestine
Large
intestine
Rectum
Anus
Figure 3.10 Digestive system
39
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Science Form 2 Chapter 3 Nutrition
Table 3.8 Digestive processes
Digestive organ Functions
Mouth (a) Place where food is chewed and crushed.
(b) Saliva softens food whereas teeth crushes food.
(c) The tongue mixes and shapes food into bolus.
(d) The amylase enzyme in saliva digest starch into maltose.
Amylase
Starch Maltose
Oesophagus Transporting the bolus from the mouth to the stomach.
Muscle contraction on the oesophagus walls results
in peristalsis movement that helps move the bolus Bolus
downwards.
CHAPTER
3
Stomach (a) The stomach walls produce gastric juice that contains:
➢ Hydrochloric acid to kill bacteria and activate the protease enzyme
➢ Protease enzyme digests protein into polipeptides
(b) Food becomes semi-liquid which is called chyme.
(c) Protease enzymes digest protein into polypeptides.
Protease
Protein Polypeptides
Duodenum (a) The chyme will move from the stomach to the duodenum.
(b) The liver secretes bile which is kept in the gall bladder.
(c) The pancreas secretes pancreatic juice which contains:
➢ Pancreatic amylase enzyme digests starch into maltose
Pancreatic amylase
Starch Maltose
➢ Lipase enzyme digest fat into fatty acids and glycerol
Lipase
Fat Fatty acids + Glycerol
➢ Protease enzyme digest polypeptides into dipeptides
Protease
Polypeptides Dipeptides
Small intestine (a) From the duodenum, food that has been partially digested moves to the small
intestine.
(b) The walls of the small intestine secretes intestinal juice which contains:
➢ Maltase enzyme that digest maltose into glucose
Maltase
Maltose Glucose
➢ Protease enzyme dipeptides into amino acids
Protease
Dipeptides Amino acid
(c) Glucose, amino acids, fatty acid and glycerol are the end products of digestion.
(d) The last part of the small intestine is the ileum and this is where absorption of the
final products of digestion takes place.
Large intestine (a) Food that is not digested enters the large intestine.
(b) Reabsorption of water occurs.
Rectum Stores food that is not digested before being eliminated from the body.
40
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Science Form 2 Chapter 3 Nutrition
5. Digestion is a biochemical reaction that 7. Enzymes are produced in the body by a
happens in the body at a very low rate. This group of cells called glands. Some of the
is why the reaction needs to be accelerated examples of glands are:
with the presence of enzymes. (a) Salivary glands which secrete amylase.
(b) Small intestine which secretes maltase
6. Enzymes are made of protein. Enzymes and protease.
can increase the rate of reaction of food (c) Pancreas which secretes amylase,
digestion. protease and lipase.
(d) Gastric glands in the stomach wall
secrete gastric juice containing pepsin
enzyme. CHAPTER
Activity 3.1
Aim: To study the action of enzymes in saliva on starch. 3
Materials and apparatus: 1% starch suspension, iodine solution, Benedict’s solution, distilled water, test
tube, thermometer, Bunsen burner, glass rod, wire gauze, 250 ml beaker, test tube holder, stopwatch and
tripod stand.
Procedure:
Thermometer
A B
Beaker
5 ml of starch
suspension Water bath
at temperature
37°C
5 ml of starch
suspension
+
2 ml of saliva
Figure 3.11 The set-up of apparatus
1. The mouth is rinsed with distilled water to clean it. Then, the mouth is rinsed once again and the water
is collected in a test tube.
2. 5 ml of starch suspension is put into both boiling tubes A and B.
3. 2 ml of saliva is added into boiling tube B and the mixture is stirred using a clean glass rod.
4. 2 ml of the solution is removed from each boiling tube and placed into two separate test tubes.
5. Iodine test and Benedict’s test are carried out on both the test tubes. The observation is recorded.
6. Boiling tubes A and B are put in water bath at 37°C and the stopwatch is started.
7. After 30 minutes, step 4 – 5 is repeated on the mixture in boiling tubes A and B.
8. The observation is recorded.
41
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Science Form 2 Chapter 3 Nutrition
Observation:
Test tube Food test Beginning of experiment End of experiment
Iodine test Dark blue solution Dark blue solution
A
Benedict’s test Blue solution Blue solution
Iodine test Dark blue solution Brown solution
B
Benedict’s test Blue solution Brick red precipitate
DIscussion:
1. The final temperature was kept at 37°C because the reaction of enzymes is most active at humans’ body
CHAPTER
temperature.
3
2. Rinsing the first time is important to ensure there are no food leftovers in the mouth.
3. At the beginning of the experiment:
(a) Iodine solution in test tubes A and B were dark blue showing the presence of starch.
(b) Benedict’s solution in test tubes A and B were blue showing absence of simple sugars.
4. At the end of the experiment:
(a) Test tube A: Iodine solution and Benedict’s solution do not show any changes in colour due to the
absence of amylase enzyme in the boiling tube that can digest starch.
(b) Test tube B: Iodine solution turned brown showing absence of starch and Benedict’s solution turned
into a brick red precipitate showing the presence of glucose. This is due to the presence of amylase
enzyme in saliva.
Conclusion:
Amylase in saliva coverts starch to simple sugars.
Formative Practice 3.3
1. The statements below are related to the process of digestion that happens along the digestive tract. For
each statement, name the organ involved.
Proses Organ
(a) Proteins are digested into polypeptides with the help of protease enzymes.
(b) Secrete bile juice to elmulsify fat.
(c) Place where reabsorption of water occurs.
2. Complete the equations which show the reaction of digestion with the help of enzymes.
(a) Dipeptides Amino acid
(b) Maltose Glucose
3. Explain the purpose of carrying out the food tests below:
(a) Iodine test
(b) Benedict’s test
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Science Form 2 Chapter 3 Nutrition
3.4 Process of Absorption and Transportation of Digested Food and Defecation
Food Digestion
1. The final products of digestion which are glucose, SCIENCE INFO
INFO
amino acids, fatty acids, glycerol as well as vitamins
and minerals do not need to be digested and are 3
absorbed into the fine structures on the walls of the Each 1 cm of the small intestine has
40,000 villi. This makes the surface
small intestine called villus.
of the small intestine with villi 600
2. Villi are very tiny projections which increase the times wider. This condition increases CHAPTER
surface area for food absorption. chances for absorption of the final
products of digestion.
3. Only small sized nutrient can go through the walls of 3
intestine and the transported by the blood to the cells.
A damp surface The wall of the villus is very thin
to (one cell thick) ease
facilitates digested absorption of molecule.
food diffussing
easily.
The abundant blood capallaries
ease the process of nutrient
transportation.
The surface of small
intestine has many folds
to increase the surface
area and increase the
absorption of digested
food.
One unit of villus
Figure 3.12 Structure of villus
Experiment 3.2
Aim: To study the absorption of glucose through a Visking tube.
Problem statement: How can glucose pass through a Visking tube?
Hypothesis: Glucose can pass through a Visking tube.
Manipulated variable: Type of content in the Visking tube
Responding variable: Presence of glucose in distilled water
Constant variable: Type and size of Visking tube, time and temperature of water
Materials and apparatus: 1% starch suspension, glucose solution, Visking tube, iodine solution, Benedict’s
solution, distilled water, boiling tube, beaker, test tube, Bunsen burner, stopwatch, tripod stand, wire gauze
and thread.
Procedure:
1. Both Visking tubes are soaked in water for a while to soften them.
2. One end of both the Visking tubes is tied with a thread.
3. 10 ml of starch solution is poured into one Visking tube and 10 ml of glucose solution is poured into
another Visking tube. Both the ends of the Visking tubes are tied.
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Science Form 2 Chapter 3 Nutrition
4. The outside of both Visking tubes are rinsed with distilled water.
Distilled
5. The apparatus are arranged as shown in Figure 3.13. water
6. Benedict’s test and iodine test are carried out on the distilled water in Starch
boiling tubes T and U. suspension
Glucose
7. The observation is recorded. solution
Visking Tube
T U
Figure 3.13 The set-up of
Observation: apparatus
Beginning of experiment End of experiment
Boiling tube Food test
CHAPTER
Observation Inference Observation Inference
3
Brown Brown
Iodine test Starch absent Starch absent
T solution solution
Benedict’s test Blue solution Glucose absent Blue solution Glucose absent
Brown Brown
Iodine test solution Starch absent solution Starch absent
U
Benedict’s test Blue solution Glucose absent Brick red Glucose present
precipitate
Discussion:
1. The Visking tube represents the small intestine.
2. Glucose molecules can pass through a Visking tube whereas starch molecules remain in the Visking tube.
This is because glucose molecules are smaller in size compared to starch molecules.
3. Make sure the outside of the Visking tube is rinsed clean so that there are no traces of starch solution
and glucose solution on it in order to get accurate results.
4. Make sure the ends of the Visking tube are tied tightly so that the glucose and starch solutions cannot
pass through.
Conclusion:
Hypothesis is accepted. Glucose can pass through a Visking tube.
Transportation Process of Digestive (a) Glucose will be used to produce
Products energy in the cell respiration process.
Excess glucose is converted to
1. Digested food that is absorbed into the glycogen and stored in the liver as food
villus is then transported to body cells. storage.
These molecules then undergo the process (b) Amino acids are used to build new
of assimilation.
cells as well as to produce enzymes,
antibodies and hormones. Excess
Assimilation is the process of distributing amino acids are converted to urea and
the end product of digestion for body eliminated through urine and sweat.
cells.
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Science Form 2 Chapter 3 Nutrition
(c) Fatty acids and glycerol are used to 5. The elimination process of faeces is known
build membrane cells. Excess fatty as the defecation process.
acids and glycerol is converted to fatty
tissues then stored under the skin to
control body temperature and stored
around organs for protection.
Blood
2. The systems involved in the transportation vessels
process of digested food are:
(a) Digestive system: Breaks down large Large
and complex food molecules into intestine
smaller and simpler molecules in order CHAPTER
to be absorbed by the villus. Rectum
(b) Blood circulatory system: Transports Anus
digested food molecules to body 3
cells. Figure 3.14 Large intestine
3. Besides, transportation of digested food is
also assisted by the assimilation process
by distribute end product of digestion food Formative Practice 3.4
for respiration, formation of new cells and
regulation of body temperature. 1. Name the part of the digestive tract involved
4. Digestive and blood circulatory system as in these following processes:
well as assimilation ensure digested food (a) Absorption of final products of digestion
molecules reach body cells to be used. (b) Reabsorption of water
2. Figure 3.15 shows fine projections on the walls
TIMSS Challenge 1 of the small intestine.
A person with intestinal cancer has to undergo an
operation to remove 6 cm of ileum. In your opinion, X
will this condition affect the process of food digestion?
Explain your opinion.
Defecation
Figure 3.15
1. Undigested food like vitamins, minerals and
fibre as well as food waste and dead cells (a) Name the projection and its importance.
from the small intestine will move to the (b) State:
large intestine. (i) structure X
2. When food passes through the large (ii) its function
intestine, water together with the vitamins 3. The length of a human’s small intestine is
and minerals will be reabsorbed into the estimated to be 6 metres. State the importance
blood. of having such a long intestine.
3. This causes food waste to become semi
solid known as faeces.
4. Faeces are sent and stored in the rectum
temporarily before being eliminated
through the anus.
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Science Form 2 Chapter 3 Nutrition
Summative Practice 3
SECTION A
1. Which of the following are the necessities of food A I and II
to humans? B III and IV
I Supplies energy C II and III
II Replace hormone in the body D I and IV
III Lengthen the life span of human
IV Supplies materials for growth 5. What enzyme is needed to obtain amino acids
A I and II from the meat that we eat?
B III and IV A Lipase
CHAPTER
C II and III B Protease
D I and IV C Amylase
3
D Sucrase
2. Carbohydrate, protein and fat are three food
classes. What is the similarity between them? 6. Figure 1 shows a structure that is found on the
A Stimulate growth walls of lumen of the small intestine.
B Maintain the body health
C Supply energy to the body
D Formed by carbon and hydrogen
3. Why does a baby need to drink milk?
A Babies don’t have teeth to chew food
B The taste of milk is delicious and so it is
preferred by the baby
C Providing milk is easier than cooking food
D Milk is a source of protein that is required Figure 1
by the baby for growth What is the importance of having the structure?
A Increase the surface of absorption of digestion
4. Which of the following are the organ involved in products
the digestion of food? B Ease the movement of food from the small
I Mouth intestine to the large intestine
II Duodenum C Stimulates the movement of peristalsis in the
III Rectum intestine
IV Large intestine D Filters bacteria that are in the food that passes
through it
SECTION B
1. (a) Match the type of carbohydrate with the correct function.
Type of carbohydrate Function
Food storage in animal and humans
Cellulose
Replaces dead cells
Glycogen
Builds the structure of plant cell walls
[2 marks]
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Science Form 2 Chapter 3 Nutrition
(b) Underline the correct answer.
(i) Adult men need to take (more / less) food than women.
(ii) Old people need (more / less) food than young people.
[2 marks]
SECTION C
1. (a) There are two types of digestion which are chemical digestion and physical digestion.
Differentiate both of them.
[2 marks] CHAPTER
(b) Figure 1 shows organ X that is also involved in the digestion of food.
X 3
Figure 1
(i) Name organ X. [1 mark]
(ii) Organ X secretes juice Y during food digestion. What is juice Y? [1 mark]
(iii) A person with organ X dysfunction will have problems with digestion. State the two problems. [1 mark]
(c) The stomach is an organ that is also involved in the digestion of food.
(i) What digestion occurs inside it? [1 mark]
(ii) Based on your answer in (c)(i), write a word equation for the digestion. [1 mark]
(d) The ileum in the small intestine is the place where absorption of digested food occurs. State the adaptation
of the surface of the lumen to increase the efficiency of the process. [2 marks]
2. (a) (i) What is meant by a balanced nutrition? [1 mark]
(ii) State the factors affecting a balanced nutrition. [2 marks]
(b) Ali has a height of 156 cm and a weight of 145 kg. He has difficulty moving and is frequently tired. He
also has low self-esteem when he mingles around with his friends.
(i) In your opinion, what is the problem that Ali has? [1 mark]
(ii) Figure 2 shows a food pyramid which is a guide of food consumption for a person.
Level 4
Level 3
Level 2
Level 1
Figure 2
Which level of food pyramid must to be avoided by Ali? Explain. [2 marks]
(iii) Other than taking care of eating habits, what other good habits need to be practised by Ali? [1 mark]
(iv) Provide a lunch menu that is suitable to be taken by Ali. [3 marks]
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Theme 3: Energy and Sustainability of Life
Chapter
9 Heat
CONCEPT MAP
Effect on matter
Type of surface
Heated Cooled
Heat Heat
Expands Contracts absorption emission
Application
• Metal bridge Relationship between
• Railway tracks Heat temperature and heat
• Thermometer
• Bimetal strip in the fire
alarm
Heat flow
Conduction Convection Radiation
Natural Natural
phenomena phenomena
Conductor Insulator Earth warming by
Land Sea breeze the Sun
breeze
Access to
INFOGRAPHIC
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Science Form 2 Chapter 9 Heat
1. Heat causes an object to become hot.
9.1 Relationship between For example, we feel hot when we stand
Temperature and Heat under the Sun. This is because heat energy
released by the Sun is transmitted through
Heat is a form of energy that flows from a space and reaches the Earth.
hotter region to a colder region. 2. The Sun is the main source of heat on
Earth.
3. Besides the Sun, heat energy can be obtained from sources shown below:
Electrical appliances Burning of fuel
Most of the electrical appliances produce heat Burning of fuels such as woods and candle
energy for example electric kettle, lamp and produce flame that releases heat.
others.
The hands feel
hot because of
the heat released
Light bulb is by the flames
The hands feel switched on
hot because of
the heat released
by the lighted bulb
Source of heat
energy
Chemical reaction Friction
Most chemical reactions produce heat energy, for When two things are rubbed together, heat will be CHAPTER
example the reaction between hydrochloric acid and produced.
the magnesium tape.
Liquid hydrochloric Magnesium 9
acid
Heat Heat
Heat
Figure 9.1 Sources of heat
4. Heat is measured in joule (J). 6. Two beakers, P and Q have the same initial
mass. 100 ml of boiling water is poured
5. The quantity of heat is influenced by:
(a) Mass of material into beaker P and 250 ml of boiling water
(b) Type of material is poured into beaker Q as in Figure 9.2.
(c) Temperature of material After a few minutes, the temperature of
water in beaker Q is higher compared to the
temperature of water in beaker P.
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Science Form 2 Chapter 9 Heat
100 ml of boiling 250 ml of boiling Table 9.1 Difference between heat and temperature
water water
Thermometer
Heat Temperature
A form of energy. Degree of hotness or
coldness.
Flows from the hot Increases when heated
Beaker P Beaker Q region to the cold and decreases when
region. cooled.
Figure 9.2
Measured in Joule (J) Measured in Celsius (°C)
7. The situation shows that the total heat unit. or Kelvin (K) unit.
energy in beaker Q is higher compared Depends on the type Depends on the
to beaker P, although the temperature of of substance, quantity movement of the particles
boiling water poured is the same.
of the substance and in the substance.
the temperature.
8. Although temperature is related to heat,
they are different physical quantities.
Temperature is the measurement of the Common Error
degree of hotness or coldness of an object.
Objects with the same temperature posseses
the same quantity of heat.
9. Temperature is measured in degree Celsius The quantity of heat in an object depends on
(°C) or Kelvin (K) with a thermometer. the mass, temperature and the type of material
used.
10. Figure 9.3 shows a glass of water with an
initial temperature of 100°C is placed under
the fan. After 15 minutes, the temperature
decreases gradually.
Formative Practice 9.1
1. Figure 9.4 shows two beakers heated at the
same heating rate. Beaker B contains twice
the volume of water in beaker A.
Temperature: 100°C 60°C
CHAPTER
Time: 0 minute 15 minutes
9
Figure 9.3
11. This shows that the temperature of a
substance depends on the movement of
the particles in the substance.
Beaker A Beaker B
12. The condition in Figure 9.3 shows the Figure 9.4
temperature of water decreases when the (a) Discuss the quantity of heat supplied by
movement of the particles in the water the flame to both beakers above. Explain
decreases as well. your answer.
(b) If the water in both beakers are heated
13. Table 9.1 shows the difference between heat for 10 minutes, compare the difference in
and temperature.
temperature for both beakers. Explain your
answer.
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Science Form 2 Chapter 9 Heat
4. When the pot is heated on the fire, the
9.2 Heat Flow and Thermal particles at the bottom part of the pot that
Equilibrium receives direct heat from the flame will
Heat Flow vibrate actively. These particles will collide
with their neighbouring particles and heat
1. When two objects with different transfer takes place. In this way, the heat is
temperatures are in contact, heat flows from transferred to the whole pot.
the hot object to the cold object.
5. This process continues until there is no
Object Object Object Object difference in temperature inside the pot.
A B A B
100°C 28°C 36°C 36°C Heat is transferred from
metal through the
vibration of particles
Figure 9.5 The flow of heat from the hot object to the
cold object
Food
2. The temperature of object A decreases
because object A loses heat whereas the
temperature of object B increases because
it gains heat from object A. Figure 9.6 Heat flow through conduction
3. The heat flow stops when the two objects 6. The rate of heat transfer through conduction
reach the same temperature. is different for different substances.
Generally, metal have a higher heat transfer
4. The rate of heat flow depends on the
difference in temperature between two rate.
objects. The greater the difference in 7. Conduction also happens in liquid and
temperature between the two objects, the gas. However, the heat transfer through
faster the heat flow takes place. conduction in liquid and gas are not
5. The heat flow takes place through these noticeable.
three forms, they are;
(a) conduction 8. Observation:
(b) convection Thumbtack A falls off first, followed by
(c) radiation thumbtacks B, C, D and E because the CHAPTER
heat is transferred from the hot region to
Conduction the cold region. 9
Conduction is the process of heat transfer Wooden
from a hotter region to a colder region block Thumbtack
through a solid medium when in contact. Wax
Iron rod
1. The particles of a solid are arranged very A B C D E
closely together. Bunsen Retort
burner stand
2. During the process of heat transfer, the
particles that receive heat energy, vibrate
faster and collide with neighbouring
particles frequently. Figure 9.7 The set-up of apparatus
3. In this way, the heat is transferred to the Thumbtacks A B C D E
whole medium.
Time taken to fall (min) 5 10 15 20 25
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Science Form 2 Chapter 9 Heat
9. Heat is transferred via conduction through (b) Heat is transferred through liquids via
solid from a hot region to a cold region. convection from a hot region to a cold
region.
Convection 5. Convection in gas
Convection is the process of heat transfer Observation:
from a hotter region to a colder region The smoke from the wooden splinter
through fluids (liquids or gases). moves downwards and moves upwards
onto the side of the candle.
1. When a fluid is heated, the hotter fluid Smoke
expands, becomes less dense and rises. Incense
Whereas the colder fluid becomes denser
and goes down replacing the empty space Gas
left by the hot fluid. jar T-shaped
Lit cardboard
2. The circulating movement of fluids that candle
rises and falls continuously is known as the
convection current.
Figure 9.10 The set-up of apparatus
3. Figure 9.8 shows the heat flow through
liquids via convection.
(a) When the air above the lit candle is
heated, the air expands and becomes
less dense. The colder air moves
downwards to replace the hot air.
(b) Heat is transferred through air via
Hot water convection from a hot region to a cold
Cold water will rise region.
will go down
Figure 9.8 The flow of heat via convection Radiation
4. Convection in liquids:
Radiation is a heat flow or transfer from
one source of heat to its surroundings
Cold water without any medium (vacuum).
moves
downwards Hot water
CHAPTER
Convection
Potassium currents 1. The Earth receives heat from the Sun
9
permanganate through radiation.
crystal
Figure 9.9 Convection in liquids
Observation: Sun
The purple streaks of potassium Earth
permanganate crystal are moving in cycle
as shown in Figure 9.9. Figure 9.11
2. When the hand is placed near the bonfire
(a) When the water is heated, the water at as in Figure 9.12, the hand will feel the heat.
the bottom expands and becomes less This is because the heat is transferred from
dense and moves upwards. The colder the bonfire to the hand through radiation.
water that is denser moves downwards
and replaces the hot water.
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Science Form 2 Chapter 9 Heat
4. The hands feel warm showing that the
heat is transferred through radiation
because the air in the bell jar has been
removed by the vacuum pump (Figure
9.13). This show that heat flows in vacuum
through radiation.
To switch
Figure 9.12 Warming our body with a bonfire
Bell jar
3. The rate of heat flow is influenced by the
type of the surface, temperature and surface
area of the object. Hand
Bulb
INFO
SCIENCE INFO
To vacuum pump
Heat that is transferred via radiation is
known as heat radiation. Heat radiation is an Figure 9.13 Heat transfer through a vacuum
electromagnetic wave that can travel through
a vacuum at the speed of light. Heat radiation
can be absorbed and reflected.
Heat Flow
Conduction Convection Radiation
Medium • Takes place in • Takes place in • Takes place in
solid. fluid. vacuum. CHAPTER
• Heat is transferred • Heat is transferred • Heat flows in
How is heat through the vibrating by the moving the form of
transferred? particles that are in of convection electromagnetic 9
contact. current. waves.
Figure 9.14 Heat flow
Heat conduction
INFO
Heat Flow in the Natural Phenomena
1. Several natural phenomena happen based on heat flow.
2. These natural phenomena are:
(a) Earth warming by the Sun
(b) Sea breeze and land breeze
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Science Form 2 Chapter 9 Heat
Earth Warming by the Sun 3. The cold air from the surface of the sea
that is denser is drawn in to replace the air
that has moved upward. This movement is
known as the sea breeze.
Land Breeze
Cold air
Hot air
Figure 9.15 Earth warming by the Sun Land
Sea
Sea
1. The Sun’s radiation is the propagation of
electromagnet waves in a straight line. The Figure 9.17
heat from the Sun propagates to the Earth 1. At night, the land cools faster than the sea.
at the speed of light. 2. The air on the surface of the sea is warmer,
2. Heat cannot be transferred to the Earth becomes less dense and moves upward. The
through conduction or convection because cold and denser air from the surface of the
there is a vacuum between the Earth and land replaces the warm air that has moved
the Sun. Thus, heat from the Sun reaches upwards. This movement of the air is known
Earth through radiation. as the land breeze.
3. The Sun is the main source of heat for the
Earth. If there is no Sun, water would freeze Land breeze
and the surrounding temperatures would
become too cold and not suitable for living 3D MODEL
things.
4. Warming of the Earth by the Sun causes
change in the climate and natural
Daily Application
Daily Application
phenomena likes sea breeze, land breeze, Daily Application
How can the flow of heat be applied in order to
El-nino phenomenon, storms and others.
Sea Breeze maintain the temperature in a house or building?
-
P
21
AK
PAK-21
CHAPTER
Hot air
9
Cold air
Land
Sea
Sea
Heat Conductors and Heat Insulators
Figure 9.16
1. During the day, the land heats up faster A heat conductor is a substance that
compared to the sea. allows heat to flow through it easily.
2. The air at the surface of the land expands,
becomes less dense and moves upwards. 1. Metal substances like silver, mercury,
aluminium, lead, cuprum, iron and zinc
are good heat conductor.
Sea breeze
3D MODEL
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Science Form 2 Chapter 9 Heat
2. Good heat conductor becomes hot easily
when heated and becomes cold easily when HOTS Challenge 1
cooled.
Mother pours hot coffee into two porcelain cups.
She leaves an iron spoon in cup A.
A heat insulator is a substance that
prevents or slows down the rate of heat
flow through it.
3. Non-metal substances like wood, plastic,
asbestos, cork, water, air and polystyrene Cup A Cup B
are good heat insulators. Figure 9.18
4. Good heat insulators are substances that After a few minutes, the coffee in cup A is colder
take time to become hot when heated and compared to the coffee in cup B. Why?
are slow to cool down when cooled.
The Uses of Heat Conductors
Mercury is a metal in the form of a
liquid and is used in thermometers
to detect changes in temperature.
Cooking utensils such as saucepans and
pots are usually made from aluminium or
steel so that heat can be transferred to the The bottom of an iron is made
food quickly. of metal (iron and steel) that can
conduct heat to clothes to smooth
them.
Radiators are made of metals such as copper CHAPTER
to allow heat to flow through them easily to the
surrounding. 9
Figure 9.19 The use of heat conductors
The Uses of Heat Insulator
Table 9.2 The uses of heat insulators
Materials Uses
Fibreglass or polystyrene Used as an insulator in the wall of a refrigerator or ice box to maintain the
cold temperature.
Wood or plastic Used in the handle of utensils so that the hand does not get burned while holding it.
Woolen blanket or cloth Used for warming the body by trapping a layer of air.
Cork, asbestos, tiles Used as a base for hot cooking utensils.
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Science Form 2 Chapter 9 Heat
INFO
SCIENCE INFO
Cling film
The Singapore National University Hospital uses cling film to wrap up
newly born babies to reduce heat loss. This is done because towels
and cloths conduct heat more easily to their surroundings compared
to cling film. The cling film is a good insulator compared with normal
cloth like cotton cloth.
Figure 9.20 The baby is
wrapped with a cling film
Activity 9.1
Aim: To study the uses of different materials as insulators.
Problem statement: Are all materials good heat insulators?
Hypothesis: Cotton and paper are good heat insulators, and aluminium is a good heat conductor.
Manipulated variable: Type of insulators
Responding variable: Final reading of the temperature of the water
Constant variable: Volume of water in the flat-bottom flask
Material and apparatus: Aluminium foil, cotton, paper, hot water, cork, stopwatch, flat-bottom flask and
thermometer.
Procedure:
1. Four flat-bottom flasks are filled with 250 ml of hot water (90°C) and the apparatus is prepared as in
CHAPTER
Figure 9.21.
9
2. The final temperature reading is recorded after 15 minutes.
Thermometer Thermometer
Hot water Hot water
A B C D
Not covered Covered with Covered with Covered with
paper cotton aluminium
Figure 9.21 The set-up of apparatus
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Science Form 2 Chapter 9 Heat
Observation:
Flat-bottom flask Initial temperature of water (°C) Final temperature of water (°C)
A 90 72
B 90 81
C 90 84
D 90 75
Discussion:
1. The flat-bottom flask A is a control experiment as comparison with the results of flat-bottom flasks B, C
and D.
2. The final temperature of the water in the flat-bottom flask A is the lowest because the flask does not have
any insulator.
3. The final temperature of the flat-bottom flask C is the highest because cotton is a good heat insulator.
Conclusion:
1. Hypothesis is accepted. Cotton and paper are good heat insulators and aluminium is a good heat
conductor.
2. Good insulators trap layers of air which slows down the flow of heat.
Formative Practice 9.2
2
1. Why is the freezer located at the top of the refrigerator? HOTS Challenge
2. The Earth receives heat from the Sun through radiation.
Why? Why are you encouraged to wear
layered clothing compared to wearing
3. The metal spoon used to stir the hot coffee feels a thick jacket during the winter?
hotter compared to the plastic spoon. Explain this
statement. CHAPTER
9.3 Principle of Expansion and 3. Figure 9.22 shows the electric cable being 9
fixed a little loose to prevent the cable from
Contraction of Matter
snapping as a result of contraction due to
the cold temperature at night.
1. When an object is heated, the particles
have more energy. These particles vibrate
or move faster and the distance among the
particles increasing, causing the volume to
increase. The increase in size is known as
expansion.
2. The opposite happens, when the object
is cooled. The particles vibrate or move
slower and the distance among the particles Figure 9.22 Electric cables during the day
decreases, causing the volume of the object
to decrease. The decrease in size is known 4. Table 9.3 shows the changes to the three
as contraction. states of matter when heated or cooled.
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Science Form 2 Chapter 9 Heat
Table 9.3
State of
matter Heated Cooled
Solid • When the solid is heated, the particles • When the solid is cooled, the vibration of
in the solid vibrate faster causing the the particles is slower and the distance
distance among the particles to increase. among the particles is closer. The volume
The volume increases and expansion decreases and contraction occurs.
occurs.
Liquid • When the liquid is heated, the movement • When the liquid is cooled, the movement
of the particles in the liquid is more of the particles becomes slower and the
vigorous and the distance among the distance among the particles decreases.
particles also increases. The volume The volume decreases and contraction
increases and expansion occurs. occurs.
Gas
• The gas molecules move rapidly • At a colder temperature, the movement
compared with the liquid. When the gas of the gas molecules is slower and the
is heated, the gas molecules move away distance among the molecules is closer.
from one another. The increase in volume The volume decreases because gas
is caused by the expansion of the gas. contracts.
CHAPTER
Activity 9.2
9
Aim: To study the effect of heat towards the expansion and contraction of solids.
Material and apparatus: Metal balls and ring, Bunsen burner, coloured liquid, tap water, ice, glass tube,
beaker, conical flask.
Procedure Observation Discussion
A Expansion and contraction of solid 1. The metal ball 1. The inside diameter
1. A metal ball is passed through the metal ring as in can go through of the ring is
Figure 9.23(a). the ring before slightly larger than
2. The metal ball is heated with the Bunsen burner heating. the diameter of the
for 5 minutes. Then, the metal ball is passed ball.
through the metal ring once again as in Figure
9.23(b).
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Science Form 2 Chapter 9 Heat
Procedure Observation Discussion
3. The metal ball is left to cool and the step is 2. The metal ball 2. The size of
repeated. does not go the metal ball
through the increases after
Holder
LoopLoopLoop HolderHolderHolder MetalMetalMetal HolderHolder ring after being it is heated and
ballballball heated. this shows that
3. The metal ball the metal ball has
can go through expanded.
Metal ballMetal ballMetal ball LoopLoop Loop the ring after it is 3. The metal ball
cooled. goes back to its
(a) Before heating (b) After heating original size after
it is cooled and
Figure 9.23 this shows that
the metal ball has
contracted.
B The expansion and contraction of liquid 1. The level of the 1. The level of
1. The initial level of the coloured water is marked. coloured water coloured water
2. The apparatus is set up as shown in Figure 9.24 and increases when it increases because
the conical flask is put into hot water. is heated. liquid expands.
3. Then, the round-bottomed flask is put in water 2. The level of 2. The level of
containing ice. coloured water coloured water
decreases when it decreases when
Glass tube
is cooled. the liquid
Cork contracts.
Conical flask
Coloured water
Figure 9.24 The set-up of apparatus CHAPTER
C Expansion and contraction of gas 1. The size of the 1. The size of the
1. Apparatus is prepared as in Figure 9.25. balloon increases balloon increases 9
2. Hot water is poured into the basin and left for 5 when the conical because the air in
flask is put into
the conical flask
minutes. the hot water. expands.
3. Then, the conical flask is left in water containing ice 2. The size of the 2. The size of the
for 5 minutes.
balloon decreases balloon decreases
when the conical when the air in
Balloon
flask is put into the conical flask
the ice. contracts.
Hot water
Figure 9.25 The set-up of apparatus
Conclusion:
Heat causes solids, liquids and gases to expand and contract.
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Science Form 2 Chapter 9 Heat
The Uses of Expansion and Contraction of Matter in Our Daily Life
Concrete road Mercury
Concrete roads are
built with soft material
for expansion during
hot days. This prevents Figure 9.27 Laboratory thermometer
the concrete road from Mercury is a liquid metal that can conduct heat well.
cracking. Figure 9.26 Mercury expands and contracts uniformly with a change
Concrete road in temperature.
Railway track Rollers on the metal bridge
Small spaces The metal bridge is usually built with space for
expansion where one end of the bridge is fixed
and the other end is supported by rollers. This
enables the bridge to expand and contract without
damaging the wall.
Space for
Railway track
expansion Fixed end
Figure 9.28 A little space between the railway
tracks
The railway track is fixed with spaces as shown
in Figure 9.28 to allow the track to expand during Rollers
hot days. This can prevent the track from bending
and prevent the train from sliding away from the Figure 9.29 Metal bridges with rollers
railway track.
Bimetallic strip in fire alarm devices
A bimetallic strip is usually used in fire alarm for switching on the alarm when a fire breaks out.
CHAPTER
1 The flame from 4
9
Electric The bell
bell the fire heats up rings.
the bimetallic strip.
Battery
Bimetallic Touch
strip point
2 The bimetallic strip will 3 The circuit is
expand bend and touch the
touch point. complete.
Figure 9.30 A fire alarm device
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Science Form 2 Chapter 9 Heat
INFO
SCIENCE INFO
Bimetallic strip
The bimetallic strip is created by combining two types of different metals that have different rates of
expansion and contraction.
Copper
Copper Copper
Heated Cooled
Iron
Iron When heated, the bimetallic Iron
The copper and iron strip bends, with copper on the When cooled to room
are connected and outside and iron on the inside. temperature, the bimetallic strip
fixed side by side. This shows that copper expands bends with iron on the outside
more than iron at the same and copper on the inside. This
temperature. shows that copper contracts more
than iron.
Figure 9.31 Bimetallic strip
The Uses of Principle of Expansion 4. A rivet is a cleat used to combine or join two
and Contraction of Matter to Solve metal plates. The hot rivet is put through the
Simple Problems holes in the metal plates. As shown in Figure
9.34, the rounded head grips one plate
1. The principle of expansion and contraction tightly while the flat head is knocked against
of matter can be used to solve problems the other plate. When cooled, the rivet will
easily.
contract and hold both metal plates.
2. A dented table tennis ball can go back to its 2
original shape when it is put into hot water. 1
This is because the air in the table tennis Hammer
ball expands. Nail remains hot
3 Cold
Hot nail Steel CHAPTER
Dented plate Steel plate held together
tight
table tennis ball Hot water
Figure 9.34 Stages in nailing 9
Figure 9.32 Returns the table tennis ball
to its original shape
5. In order to fix an axle to the hub of a wheel,
3. A tightly closed bottle lid can be opened the axle is cooled in liquid nitrogen at a
more easily by submerging the lid part into temperature of –196°C to enable the axle to
hot water. The bottle lid will expand faster be fixed into the hub of the wheel.
than the glass bottle. This enables the lid to
be opened easily.
Axle
Bottle
Hub of
wheel
Hot water
Metal lid
Figure 9.35 Fixing the axle to the hub of wheel
Figure 9.33 Submerging the metal lid into hot water
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Science Form 2 Chapter 9 Heat
Formative Practice 9.3
1. State the characteristics of mercury that make it suitable for thermometers.
2. Figure 9.36 shows a bimetal invar and aluminium strip.
(a) Draw the changes that happen to the bimetal strip when it is heated. Aluminium
(b) State two equipment that use bimetalic strips. Invar
3. Explain why small spaces are prepared in between the railway tracks and Figure 9.36
concrete roads.
9.4 Relationship between Types 2. A dark and dull surface absorbs heat
better than a bright and shiny surface.
of Surface of Object, and Heat
Absorption and Emission
TIMSS Challenge 1
1. All objects absorb and emit heat. The ability
to absorb and emit heat depends on the On a bright day, you feel cold when you put on bright
type and colour of the surface as well as the coloured clothing. Why?
surrounding temperature.
Activity 9.3
Aim: To study if a dark and dull object absorbs heat better than white and shiny object.
Problem statement: Which surface absorbs heat better?
Hypothesis: A dark and dull object absorbs heat better than a white and shiny object.
Manipulated variable: Type of surface
Responding variable: Final reading of the air temperature
Constant variable: Distance from the heat source
Material and apparatus: Block of wood, rubber stop, thermometer, Bunsen burner, stopwatch, conical flask
painted white and another conical flask painted black.
CHAPTER
Procedure:
9
Thermometer
Conical flask Conical flask
painted black painted white
M N
Figure 9.37 The set-up of apparatus
1. The apparatus is set up as shown as in Figure 9.37. Two conical flasks are put at a distance of 10 cm away
from the Bunsen burner.
2. The initial temperature of air in each flask is recorded.
3. The Bunsen burner is turned on.
4. The final temperature is recorded, after 15 minutes.
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Science Form 2 Chapter 9 Heat
Observation:
Temperature of the air (°C)
Conical flask
Initial Final
M 28 34
N 28 30
Discussion:
The temperature of the air inside conical flask M is higher than the temperature of the air inside conical flask
N. This is because the dark and dull surface absorbs heat better than the white and shiny surface.
Conclusion:
Hypothesis is accepted. The dark and dull object absorbs heat better than the white and shiny object.
Activity 9.4
Aim: To study if a dark and dull object radiates heat better than white and shiny object.
Problem statement: Which surface radiates heat better?
Hypothesis: The dark and dull object radiates heat better than the white and shiny object.
Manipulated variable: Type of surface
Responding variable: Final reading of the water temperature
Constant variable: Volume of hot water
Material and apparatus: Asbestos, rubber stop, hot water, thermometer, stopwatch, conical flask painted
white and another conical flask painted black. CHAPTER
Procedure:
Thermometer 9
Conical flask Hot water Conical flask
painted black painted white
P Q
Figure 9.38 The set-up of apparatus
1. The apparatus is set up as shown in Figure 9.38. 250 ml of hot water is filled into both conical flasks.
2. The initial temperature of the water in each conical flask is recorded.
3. After 15 minutes, the final temperature of the water in each conical flask is recorded.
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Science Form 2 Chapter 9 Heat
Observation:
Temperature of the water (°C)
Conical flask
Initial Final
P 95 60
Q 95 73
Discussion:
The temperature of the water in the conical flask P is lower than the temperature of the water in the conical
flask Q. This is because the dark and dull surface emits heat better than the white and shiny surface.
Conclusion:
Hypothesis is accepted. The dark and dull object radiates heat better than the white and shiny object.
Wearing bright-coloured clothes
during outdoor activities or
during hot weather can reflect
the radiation of heat from the
Sun.
The petrol tank of a petrol tanker is
painted silver and shiny because a
bright surface does not absorb much
heat.
Application of
heat absorption
and emission in
our daily life
Cooking utensils or the base of The compressor at the back of
pots are usually black to fasten the the refrigerator is usually black
cooking of food because the black to enable quick heat emission
colour is a good heat absorber. into its surroundings.
CHAPTER
9
Figure 9.39 Application of absorption and emission of heat in our daily life
Heat Concept in Daily Life
1. Green building technology practises the importance of the natural environment in buildings.
The main aim of this technology is to reduce the effect on the environment and human health
as a result of rapid development.
2. Features of green building:
(a) Using recycled materials.
(b) Using water efficiently, for example using recycled water or rain water.
(c) Using renewable energy like solar energy.
(d) Using environment-friendly equipment.
(e) Reducing damage to the original landscape. Green building
(f) Using good ventilation, drainage and lighting system. concept
INFO
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Science Form 2 Chapter 9 Heat
Glass roof
Solar panel Solar water heater
Water tank
for rain water
Lawn
Glazed
window
Figure 9.40 Example of green house concept
3. Table 9.4 shows the features of the green house concept used as in Figure 9.40.
Table 9.4
Features Uses
Solar panel Changes light energy to electrical energy
Solar water heater Heats up the water without using electrical energy
Water tank for rainwater Collect rainwater and can be used to water plants or to wash cars
Glazed windows Helps to cool the house
Glass roof Allows light to enter the house
Grass and trees on the lawn Maintains a green landscape CHAPTER
Formative Practice 9.4 9
1. (a) Complete the following table.
Type of surface Absorption of heat Emission of heat
Dark Good
Bright
Dull
Shiny Weak
(b) Based on you answers in (a) what is the characteristic of the outer surface of an electric kettle so that
it can keep heat for longer time?
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Science Form 2 Chapter 9 Heat
Summative Practice 9
SECTION A
1. What is the conclusion that can be made from the 5. A thermos can maintain the temperature of its
statement below? contents for a long period of time. Which of the
following is the special characteristic that allow
Objects P and Q are in contact with one for the avoidance of heat loss through radiation?
another. The temperature of P is higher than A Cork cover
object Q. B Plastic container
C Silver-coated surface
A Heat transfer is only from P to Q D Vacuum
B Heat transfer is only from Q to P 6. Figure 1 shows a natural phenomenon that occurs
C The rate of heat transfer from P to Q is higher due to heat flow.
from Q to P
D The rate of heat transfer from Q to P is higher
than P to Q Hot air
Cold air
2. Why are we advised to wear light-coloured
clothing while doing outdoor activities?
A Light-coloured clothing can reflect the heat Land
Sea
from the Sun Sea
B Light-coloured clothing can absorb heat from Figure 1
the Sun What is the phenomenon and when it happens?
C Light-coloured clothing can easily absorb
sweat. Phenomenon Time
D Light-coloured clothing can easily be seen.
A Sea breeze Daytime
3. Which of the following are true about temperature? B Land breeze Daytime
I Temperature is the total energy that is C Sea breeze Night
contained in a body.
II Temperature cannot be measured. D Land breeze Night
III The S.I. unit for temperature is Kelvin (K).
IV Temperature is the degree of hotness of a 7. Figure 2 shows the construction of a railway track.
CHAPTER
body. Small spaces
A I and II
9
B III and IV
C II and III
D I and IV
4. Which of the following arrangement is correct Railway track
about the rate of heat transfer in ascending order?
A Conduction → Convection → Radiation Figure 2
B Radiation → Conduction → Convection Why do railway tracks connect with small spaces
C Convection → Radiation → Conduction as shown in the figure above?
D Conduction → Radiation → Convection A So that the train can move straight.
B So that the train can change direction.
C So that the tracks last long.
D So that the track has spaces when expanding
in hot weather.
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Science Form 2 Chapter 9 Heat
SECTION B
1. (a) Determine whether the following materials are heat conductor or heat insulator. Tick (✓) the correct box.
Material Heat conductor Heat insulator
(i) Aluminium
(ii) Wool
[2 marks]
(b) Tick (✓) on the correct statements about heat.
(i) A form of energy.
(ii) Degree of hotness or coldness of an object.
(iii) Measured in Joules.
(iv) Depends on the movement of particles in a matter.
[2 marks]
SECTION C
1. Figure 1 below shows a set up of an experiment to study heat transfer.
Thermometer
Polystyrene cover CHAPTER
Boiling
water 9
Glass beaker
Figure 1
(a) (i) Identify the type of heat transfer studied. [1 mark]
(ii) After the apparatus is left for 10 minutes at room temperature, the thermometer shows a temperature
reading of 60 °C. Suggest an improvement that needs to be done to the glass beaker so that the
water temperature becomes the same as room temperature faster. [4 marks]
(iii) Wrapping the beaker with a towel will reduce the rate of reduction of water temperature. Explain why
this phenomenon occurs. [2 marks]
(b) Why does the flattened ping pong ball return to its original shape after being put into hot water?
[2 marks]
(c) Give one example of an application of the effects of heat towards the expansion of matter in daily life.
[1 mark]
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ANSWERS
Chapter Summative Practice 1 produces its own food whereas the
1 Biodiversity consumer is the organism that eats
SECTION A other organisms.
Formative Practice 1.1 1. D 2. B 3. D 4. A 2. (a) Sparrow and frog.
(b) • Paddy → Rat → Eagle
1. Habitat and climate 5. A 6. C 7. C 8. C • Paddy → Grasshopper → Frog →
2. Animals – goats, chickens and cows; SECTION B Eagle
Plants – spinach, mustard leaves, mangoes • Paddy → Caterpillar → Sparrow
3. Furniture industry, rubber products 1. (a) (i) Durian, cow → Eagle
industry (ii) Rafflesia, hornbill (c) The population of caterpillar
4. Advantages: Economic resource (b) (i) Elephant increases.
increases because of an increase in (ii) Polar bear
agriculture products HOTS Challenge
Formatif 1 2
Disadvantages : Destruction of SECTION C Pr
wildlife’s original habitats. 1. (a) (i) The diversity of living Death animal and death plants will not
organisms on this Earth decay.
includes plants, animals and
HOTS Challenge microorganisms.
Formatif 1 1
Pr
(ii) Law enforcement because Formative Practice 2.2
It's reasonable. The numbers of perpetrators will be scared
orangutans and Sumatran rhinos are very of harsh laws such as prison 1. (a) (i) Carbon dioxide
small. Hunting can lead to the extinction or fine with high amount.// (ii) Oxygen
of the species. Awareness campaign so that (b) (i) Photosynthesis
(ii) Respiration
the community will be aware (c) Decomposition
TIMSS Challenge 1 of their role and the change 2. (a) Burning of rubbish / Disposal of
in behaviour is long lasting.
cigarette butts
B Goat is a mammal that gives birth and (iii) Provide logs (b) • Excessive release of carbon
feeds its baby. Build buildings / furniture //
Habitat for rattan dioxide
Build furniture // • Percentage of carbon dioxide in
HOTS Challenge Herbal plants the air exceeds 0.03%
Formatif 1 2
Pr
Produce medicine //
A bat is a mammal because it has Food Daily Application
obvious characteristics similar to a Vegetables / fruits from the
mammal’s, they give birth, nurse its forest The duck, because it is the predator to
young, are warm-blooded and breathes (b) Restriction of fires // Can cause golden apple snails.
through its lungs. the burning of forest
Destroys the habitat of flora and
fauna Formatif 1 3
Formative Practice 1.2 Restriction of throwing trash HOTS Challenge
Pr
1. Help scientist identify clearly the // Damages the scenery / Snake are dangerous to humans because
characteristics of the animals. Reduces tourist attractions
2. Vertebrates are animals with snakes are poisonous animals.
backbones, for example cows while
invertebrates are animals without Chapter Ecosystem
2
backbones like ants. TIMSS Challenge 1
3. No. Some non-flowering plants such The rat population increases, causing the
as Gnetum and conifers can produce rice harvest to decrease.
Formatif 1 1
Pr
seeds through cones. HOTS Challenge
4. Monocotyledon have fibrous roots, one
cotyledon and paralleled vein leaves. This is because of the increase of the rat
While dicotyledons have tap roots, two population in the cornfields caused by Formative Practice 2.3
cotyledons and network-like vein leaves. the absence of the prey, that is the snake 1. Mutualism, commensalism and
eating the rat. parasitism
TIMSS Challenge 2 Formative Practice 2.1 2. Yes, because breeding only occurs
within the same species only.
D Cockle, crab, cockroach, spider 1. The producer is the organism that
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Science Form 2 Answers
3. No, because the excessive use of on living trees and absorb 3. (a) To determine the presence of
pesticides will destroy the soil. nutrients from them. starch
4. The plankton population dies. • Mushrooms reside on (b) To determine the presence of
Plankton needs an average dead trees while rafflesia glucose
temperature to continue to can cause the host that is
resided on to die.
survive.
(iii) Pigeon orchids do not absorb TIMSS Challenge 1
water and nutrients from
Formative Practice 2.4 the host. // Pigeon orchids No. No digestive process at the ileum.
absorb water from the The process that takes place at the ileum
1. Good effect: The country’s economy environment and carry out is the absorption of digested food.
increases. photosynthesis.
Bad effect: Destruction of habitats
and environmental pollution. Formative Practice 3.4
2. Cause: The drainage system is not Chapter 1. (a) Small intestine
maintained properly, for example too 3 Nutrition (b) Large intestine
much of rubbish clogging the drains. 2. (a) Vilus, its function is to increase the
Steps: Maintenance of the drainage surface area of the small intestine.
system at least one a month. Formative Practice 3.1 (b) (i) Blood capillary
3. • Using organic fertiliser. 1. (ii) to transport digested food to the
• Using biological control to (i) Protein Builds and repairs cells in the body.
exterminate pests. 3. Allows the digestive process to be
tissues
carried out to the maximum.
Summative Practice 2 (ii) Carbohydrate Provides energy
(iii) Fibre Prevents Summative Practice 3
SECTION A
constipation SECTION A
1. B 2. C 3. D 4. A
1. D 2. D 3. D 4. A
5. B 6. C 7. B 2. (a) Scurvy
(b) Eat more fruits and vegetables that 5. D 6. A
SECTION B are high in vitamin C. SECTION B
1. (a) (i) 1. (a) (i) Cellulose - Builds the
Formatif 1 1
Pr
HOTS Challenge
structure of plant cell walls
Rice provides energy. Vegetables and Glycogen - Food
storage in animal and
fruits contain vitamin C to maintain humans
our health whereas fibres prevent (ii) Glycogen
constipation. Fried chicken and fish
Mutualism provide protein which repairs injured (b) (i) more
(b) (i) True tissues. (ii) less
(ii) False SECTION C
Formative Practice 3.2
SECTION C 1. (a) • Physical digestion produces
1. (a) Mutualism, Commensalism, 1. Contains seven classes of food with the small food particles whereas
Parasitism correct ratio. chemical digestion produces
(b) • Tiger – sharp claws and long 2. Pregnant women need more energy simple molecules.
fangs to grip and kill prey compared to women who are not • Chemical digestion involves
• Deer – a small body and strong pregnant. This is because pregnant enzymes whereas physical
leg muscles to run fast to save women need to pass nutrients to the digestion does not involve
themselves foetus. enzymes.
(c) Competing for mates does not 3. Amir, because he does a lot of active (b) (i) Pancreas
occur within different species movements that require more energy. (ii) Pancreatic juice
because fighting for mates only 4. Eat according to the correct amount./ (iii) • Pancreatic juice cannot be
happens to organism of the Eat at the fixed time. secreted.
same species. • Starch digestion is less
(d) (i) Mushroom - saprofitism Formative Practice 3.3 efficient.
Rafflesia - parasitism 1. (i) Stomach • Protein digestion is disturbed.
(ii) • Mushrooms grow on (ii) Liver • Fat digestion does not occur.
dead and decaying trees (iii) Large intestine (d) Filled with fine projections known
to obtain nutrients from 2. (a) Protease as villi to increase surface area
them while rafflesia grow for absorption.
(b) Maltase
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Science Form 2 Answers
2. (a) (i) Food that contains all food Formative Practice 4.2 (iii) This disease can be
classes that are required by prevented from spreading
the body in correct quantities 1. Using the body’s defence mechanism with isolation methods
to fulfil the needs of the body. 2. (a) which is devices, items
(ii) Gender / Climate / and personal clothes of the
Occupation / Age / Health (b) patient are isolated from
condition / Body size (any (c) other people.
two)
(b) (i) Obesity (d) Chapter
(ii) Stage 4 3. Natural immunity is the antibody 5 Water and Solution
Contains fat and oil produced by the body while artificial
(iii) Regular exercise / don't eat immunity is the antigen or antibody
food with high cholesterol Daily Application
(iv) • Carbohydrate - White rice, injected into the body directly. To increase the boiling point of the water
bread 4. Children are more susceptible to
• Protein without fat - Fish, diseases because their immune so that food can be cooked longer.
grilled chicken, steamed system is weak and has not developed
meat fully. Therefore, immunisation is very HOTS Challenge
Formatif 1 1
• Fibre - Vegetables important for them. Pr
(Cucumber, tomato, salad)
• Plain water Summative Practice 4 The hairdryer produces hot air. The
presence of heat and wind increase water
SECTION A evaporation. Suzi’s clothes dry faster.
Chapter 1. C 2. C 3. D 4. D
4 Human Health
5. D 6. B 7. B Formative Practice 5.1
Formative Practice 4.1 SECTION B 1. Sweat evaporates faster in windy
1. (a) Group 1: Leptospirosis, H1N1 conditions.
1. Infectious diseases are diseases that 2. The effect of the surface tension force
can spread from one individual to Group 2: Cancer, Diabetes causes droplets of water/ liquid to form
another individual. (b) (i) infectious in spheres as they fall onto a surface.
(ii) vector
2. Pathogens are organisms that cause 2. (a) (i) Vector 3. (a) Cohesive force
illnesses while vectors are animals that (ii) Air (b) Adhesive force
transmit the pathogen from the host to (b) (i) Immunisation
another individual. For example, the (ii) Antibody
dengue virus is carried by its vector, Formative Practice 5.2
that is the Aedes aegypty mosquito. SECTION C 1. Solute – iodine crystals; solvent –
3. (a) vibro bacteria, fly alcohol; solution – antiseptic.
(b) Denggue virus, Aedes aegpty 1. (a) Not the same. Pathogens are 2. (a) P: Suspended solution; Q: Collloid;
mosquito microorganisms that cause R: solution
(c) Leptospira bacteria, rat diseases while vectors are (b) P: Milk, Q: Cream cake, R: Sugar water
(d) Influenza H1N1 virus, no vectors animals that transfer pathogens (c) Mixture P
(c) Dermatophyte fungus, no vectors from one organism to another. 3. (a) Acetone
4. Air, water and touch. (b) When a patient sneezes or (b) Borax solution
coughs, water droplets that
contain pathogens will come out
HOTS Challenge from the patient's mouth and Daily Application
Formatif 1 1
Pr
nose. These water droplets will Can use lime to remove rust stains on the
The child is not protected from diseases be carried by the air, anyone clothes.
prevented by the vaccine and there is a who breathes the air will have
high probability of the child contracting high chances to be infected with TIMSS Challenge 1
such diseases. that disease.
(c) • Wear masks when being Oil spill can kill animals and pollute the
around patients. rivers/ seas.
TIMSS Challenge 1 • Patients close their mouth
and nose while coughing or Formative Practice 5.3
Sofea has a good immune system. / sneezing.
Sofea does not touch or play too near (d) (i) Ringworm 1. (a) Chlorination
Ah Mei. (ii) Yes. Ringworm is an (b) Boiling
infectious disease caused by (c) Distillation
the dermatophyte fungus. (d) Boiling
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Science Form 2 Answers
2. Reverse osmosis and ultraviolet ray 2. The fishy smell of the fish is caused by
treatment. the presence of a type of alkali, that Daily Application
3. Reuse and recycle wastes. Treat is amine. Washing your hands with When a person walks, electrons are
dangerous industrial wastes. lemon juice which is acidic in nature produced as a result of friction between
neutralises the amine and gets rid of the carpet and the shoes. Electrons are
the pungent smell. dispersed to the whole of the surface of
Summative Practice 5 the skin. A person would feel the electric
SECTION A TIMSS Challenge 1 shock when he touches the door knob/
1. A 2. D 3. B 4. A A mixture of hydrochloric acid with metal because the electrons on the hand
5. D sodium hydroxide solution produces a salt attract the positive charges on the door
knob.
solution that is sodium chloride which is
SECTION B
neutral in characteristic. Therefore, this
1. (a) (i) Homogenous mixture of two mixture does not change the colour in Formative Practice 7.1
or more substances. both pieces of litmus paper.
(ii) Substance that dissolve in 1. Water and Sun.
liquid. Summative Practice 6 2. Metal chains are fixed to the back of
(b) (i) and (iii) the oil tanker to channel electrons,
SECTION A produced as a result of friction between
SECTION C 1. D 2. C the body of the tanker and air to the
1. (a) Oxygen and hydrogen SECTION B earth.
(b) No, because flood water 1. (a) (i) Acidic properties 3. 40 cm = 2 Ω, 100 cm = x Ω
2
contains dissolved impurities. (ii) Alkali properties 40 =
100
(c) Cars are denser than water but (b) Acid + Alkali → Salt + Water x = 5 Ω x
boats are less dense than water. SECTION C
(d) Nani's wet clothes are slow to 4. R = V
dry due to the low temperature 1. (a) (i) Acidic 3 I
inside a house that slows down (ii) Types of solution I = 6 = 0.5 A
the rate of evaporation of water (iii) No because solution Q
from the surface of the wet cloth. is alkali and S might be Formative Practice 7.2
(e) Water in kettle Q due to the acidic because there are no
presence of coffee powder and changes on the blue and red 1. (a) The brightness of bulb P and Q is
sugar (impurities) in the water litmus paper. the same.
will increase the boiling point of (iv) Acidic substance is a (b) Bulb P does not light up because the
the water. substance that turn the blue circuit is not complete.
litmus paper to red.
(v) Function: The litmus paper 2. (a) 1 = 1 + 1 + 1
is an indicator to determine R 2 2 2
Chapter R = 0.67 Ω
6 Acid and Alkali the acidity and alkalinity of a V
substance. (b) I = R
3
Formative Practice 6.1 // Any suitable answer. I = 0.67 = 4.48 A
Other materials: pH paper //
1. (i) Sour; Litmus solution // Universal (c) 4.48 A = 1.49 A
(iii) Corrosive; indicator solution 3
(ii) . 7; (b) The purple colour of the liquid
(iv) Blue to red sample lessens because the TIMSS Challenge 1
(v) Red to blue acidic lime weakens/neutralises
2. Acid and alkali are used as cleaner the alkalinity of the liquid
agents because both are corrosive that sample. N S N S
can remove stains.
3. • Nitric acid is used as fertiliser. Chapter
• Citric acid is used in fruit juice 7 Electricity and Magnetism HOTS Challenge
Formatif 1 2
4. No, acid does not show its Pr
characterisctic without the presence of HOTS Challenge
Formatif 1 1
water. Pr The total number of clips attracted
increases. This happens because an
The female student’s hair is charged with increase in the diameter reduces the wire
Formative Practice 6.2 the same charge, which is the positive resistance. Therefore, the current that
1. Hydrochloric acid + Ammonia → charge. The same charges push against flows increases. The more current that
Ammonium chloride + air one another, causing the strands of hair flows through the conductor, the stronger
to stand upright. the electromagnet.
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Science Form 2 Answers
Formative Practice 7.3 (c) North
Formatif 1 3
HOTS Challenge
Pr
1. An electromagnet is a material with Iron nail
temporary magnetic effects when the The packet of potato chips will expand
current flows through the conductor.
because the pressure inside the packet
2. If the direction of the current is reversed is higher compared with the outside
the direction of the magnetic field Battery pressure.
will change while the pattern of the
magnetic field remains the same. Formative Practice 8.2
3. • Current flow through the conductor Insulated
copper wire
• Number of wire coils 1. Water, raw egg, salt water, cooked egg.
4. The electromagnet is a temporary Switch 2. (a) First class lever
(b) Scissors, plier
magnet. It can be magnetised and Sum of force
demagnetised easily. Therefore, when 3. Pressure = Surface area
the current flows, the iron core becomes South 10
a magnet and lifts scrap metal and = 0.5 × 10 –4
when the current is disconnected, the (d) Current and number of turns = 2 × 10 N m –2
5
scrap metal drops. (e) • Current: The more current
5. The empty space shows there is no that flows in a conductor, the Summative Practice 8
magnetic field in that area and this area stronger the electromagnet. SECTION A
is known as the neutral point. • Number of turns: The
more number of turns, the 1. B 2. B 3. D 4. D
Summative Practice 7 higher the strength of the 5. A 6. C
electromagnet.
(f) Electric bell // phone holder // SECTION B
SECTION A
electric circuit breaker // relay 1. (a) (i) Push
1. D 2. A 3. B 4. B switch // vehicle engine starter (ii) Pull
SECTION B (b) (iii) and (iv)
1. (a) (i) Energy that is generated Chapter
8
from animal waste and Force and Motion SECTION C
decomposition of living things 1. (a) Suitable, because the tire is wide
such as plants and animals. HOTS Challenge and does not easily sink into the
Formatif 1 1
(ii) Heat energy from the Earth’s Pr sands of the beach.
crust due to very high No. The weight of an object depends (b) – A wide tire can reduce pressure.
temperature of the Earth's on the gravitational pull in an area. The – A more elastic shock
core. stronger the gravitational pull the heavier absorber can absorb force
(b) (i) Potential energy the object. effectively and makes driving
(ii) Kinetic energy more comfortable.
Formative Practice 8.1 (c) Produces a better grip on the
SECTION C beach.
1. (a) Gravitational force.
1. (a) (i) (b) Frictional force. 1150
(d) (i) Pressure = 0.4
2. Measuring it using the spring scale.
3. More than 2 N. = 2875 N m -2
N Q N 4. 100 N 1150 + 700
(ii) Pressure =
0.4
TIMSS Challenge 1 = 4625 N m -2
(e) Helmet with face shield
(ii) The neutral point is the point In liquid Y, because the object has higher
where there are no magnetic density than liquid Y.
field lines. Chapter
(b) The closer the magnetic field HOTS Challenge 9 Heat
Formatif 1 2
lines, the stronger the magnetic Pr
field.
When water flows out from the tank, Formative Practice 9.1
there is empty space inside that tank (a) The quantitiy of heat received by the
that becomes semi vaccuum and low water is the same because the total
pressure. The outside pressure which is amount of power supplied to the heater
higher prevents the water from flowing is the same.
out. Opening the lid/cap allows air to (b) The temperature of the water in beaker
enter the tank and push the water out. A is higher than the temperature of
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Science Form 2 Answers
the water in beaker B. This is because Chapter
the volume of beaker A is smaller. TIMSS Challenge 1 10 Sound Waves
Because the total amount of heat that Brighter clothes are poor heat absorbers;
is absorbed is the same, the degree of therefore you would feel cooler in hot
heat in beaker A is bigger. weather. TIMSS Challenge 1
Faiq. This is because Faiq’s string is taut
Daily Application Formative Practice 9.4 while Naqib’s string is slack. Slack strings
cannot transfer sound waves.
The convection current is used to (a)
maintain the cooling temperature in Daily Application
buildings. Hot air moves upwards and out Type of Heat Heat
through the ventilation holes and space surface absorption release Sound reflection in the bedroom can be
in the roof. Cold air will in turn flow in reduced by adding sound absorbers such
through the windows and doors. Dark Good Good as putting carpets, hanging up curtains
and placing soft sofa sets.
Bright Weak Weak
HOTS Challenge Formative Practice 10.1
Formatif 1 1
Pr
Dull Good Good
The iron spoon is a good heat conductor. 1. Sound is produced from vibrating
It conducts heat faster to its surroundings, Shiny Weak Weak objects.
so the water cools faster. 2. In outer space, there are no air
(b) A bright and shiny surface because it is particles, only vacuum. Therefore,
Formative Practice 9.2 slow in releasing heat compared to a dark sound waves cannot be transferred.
and dull surface. 3. Sound is clearly heard through solids
1. Cold air flows to the bottom of the compared to air. This is because the
refrigerator because cold air is denser, Summative Practice 9 arrangement of particles in solids is
while hot air which is less dense, will SECTION A more compact and causes the next
move upward. In this manner, the inside particle to vibrate fast as well.
cooling is circulated efficiently. 1. C 2. A 3. B 4. A
2. The space between the Earth and 5. C 6. A 7. D HOTS Challenge
Formatif 1 1
the Sun is actually a vacuum. In a Pr
vacuum, there are no particles that can SECTION B
transfer heat through conduction and 1. (a) (i) Heat conductor The wave frequency produced by a
convection. (ii) Heat insulator supersonic aircraft is so high that it
3. Metals are good heat conductors while (b) (i) and (iii) is capable of vibrating the particles in
mirrors until the mirrors break.
a plastic spoon is a heat insulator.
SECTION C
1. (a) (i) Conduction Formative Practice 10.2
HOTS Challenge (ii) • Replace the glass beaker
Formatif 1 2
Pr
with a metal container, so 1.
Every layer of clothing will trap layers of that heat is transferred √
air inside it, thus preventing heat from quicker
escaping. This gives multiple insulators. • use wider glass beakers
so that the surface area
for heat transfer is larger
Formative Practice 9.3 (iii) A towel will trap air. Air is
a heat insulator that slows
1. Mercury is suitable to be used in liquid 2. The observer approaches a sound
thermometers because it is a liquid that the transfer of heat to the source that has a higher frequency.
expands and contracts quickly with a environment.
change in temperature. (b) The air in the ping pong ball
becomes hot through transfer of Formative Practice 10.3
2. (a) heat. The hot air will expand and
Aluminium 1. (a) 20 000
push the surface inside the ping (b) Megaphone amplifier
pong ball to its original shape. (c) hard
Invar (c) Take off the tight bottle cap by 2. Bat and dolphin
soaking the bottle cap into hot
(b) • Electric iron water.
• Fire alarm
3. To provide space when the road expands
on a hot day to prevent cracking.
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Science Form 2 Answers
Summative Practice 10 Formative Practice 11.1 The telephone screen will show
the position of constellations
SECTION A 1. A nebula is a group of large clouds and planets in the direction of
made up of dust and gasses such as pointing.
1. B 2. A 3. A hydrogen and helium.
SECTION B
2. Galaxies can be classified according to
1. (a) (i) vibrations the shapes of the galaxies. Chapter
12
(ii) slower 3. Salmah can observe the stars using Solar System
(b) (i) sofwares such as Stellarium which
shows a realistic view of the sky similar HOTS Challenge
Formatif 1 1
Pr
to using our naked eyes, binoculars or
a telescope. The kilometre unit is not suitable to be
used because its value is too large and
Louder sound Summative Practice 11 difficult to be managed.
SECTION A
(ii) TIMSS Challenge 1
1. B 2. C 3. A 4. C
The distance of the Moon from the Earth
SECTION B is shorter compared to the distance of
1. (a) (i) and (iii) Jupiter from the Earth, therefore the
(b) (i) A region that has a very Moon seems bigger.
Higher pitched sound strong gravitational attraction
such that things are sucked HOTS Challenge
Formatif 1 2
SECTION C into it including light. Pr
(ii) A large cloud that consists of
1. (a) (i) • Waves emitted by the dust and gas such as helium No, although water has been found on
transducer which moved and hydrogen. Mars, the oxygen content on Mars is very
on top of the mother's 2. (a) (i) Supergiant star low and it is difficult for living things to
abdomen. (ii) Supernova survive there.
• Repeated reflections (b) (i) False
are received by the (ii) True Formative Practice 12.1
transducer. 1. 4.19 A.U, 6.61 × 10 ly
–5
• Information from the SECTION C 2. The time the Moon takes to rotate on
reflection will form an its axis is the same as the time taken
image on the screen. 1. (a) That star will be sucked into the for the Moon to move around the
(ii) • To determine the depth of black hole as the black hole has Earth.
the ocean very strong gravity.
• To determine the position (b) For spiral galaxies, research 3. The Earth is situated closer to the
Sun compared to Mars. Therefore,
of a group of fish by shows that young stars are at the Earth gets more sunlight
fishermen the arms or branches of the
• To detect cracks in engine galaxy while old stars are at the compared to Mars and increases the
temperature on the surface of the
parts centre of the galaxy.
• To clean ornaments (c) The Milky Way galaxy is an Earth.
(iii) 3.5 – 7 MHz illustration of astronomers 4. – Contains oxygen and carbon
(b) No, because the maximum sound because the telescope needs to dioxide which are necessary for
frequency detectable by the be outside of the galaxy in order respiration and photosynthesis.
human ear is 20 000 Hz. to take a picture of the galaxy. – Contains a high content of water
(c) Stethoscope and megaphone This is impossible because the for all life processes.
(d) High amplitudes cause damage to Earth is located inside the Milky
ear drums. Way. The Milky Way is very big Summative Practice 12
and to send a telescope out from
it would take millions of years. SECTION A
Chapter (d) Blue stars are stars with the
11 Stars and Galaxies in 1. D 2. A 3. B
the Universe highest temperature and brighter
light. Most blue stars are old SECTION A
HOTS Challenge stars that are bigger than red 1. (a) (i) Moon
Formatif 1 1
Pr
and yellow stars. (ii) Earth
No, the Sun is an average size star. At (e) Students can download a (b) (i) Mars
the end of its lifespan, the Sun would skyview software onto the cell (ii) Neptune
become a white dwarf. phone and point it to the sky.
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Science Form 2 Answers
SECTION C Formatif 1 2 (b) (i) Meteor
Pr
1. (a) P: Mars HOTS Challenge (ii) Meteorite
(c) The small size and mass of the
Q: Uranus object makes it easily influenced
R: Neptune The collision between the Earth and a by the gravitational pull of the
(b) Neptune large asteroid is capable of interfering planets, moons and other space
(c) Venus, although Venus is the with the speed of the Earth’s rotation objects around it.
second planet from the Sun, the on its axis. When this happens, the (d) • Causing a tsunami
high content of carbon dioxide gravitational pull of the Sun and the • Killing life in the sea
in its atmosphere causes its planets influences the Earth and attracts • Threatening the lives of
surface temperature to be high. the Earth towards it. This causes the
(d) (i) • The sun rises in the East Earth to slip out of its orbit. residents who are near the
sea.
and sets in the West
• The position and length Formative Practice 13.1 (e) The Moon has many craters
because of the absence of
of the shadow change 1. • An asteroid is bigger than a atmosphere that can burn the
throughout the day meteoroid.
• Day and night occurs • An asteroid has its orbit while the meteoroid.
(ii) • Natural phenomena will meteoroid does not.
be disturbed 2. Meteoroids move freely in space Answers for UPSA &
• Severe tidal events in one and are influenced by the Sun and UASA Model Papers
part of the Earth that can planets around them. https://qr.pelangibooks.com/?u=G35JPJcS
cause a tsunami
• The occurrence of longer 3. Apollos and Atens.
day and night on two 13
different parts of the Earth Summative Practice
SECTION A
1. A 2. D 3. B
Chapter
13 Meteoroid, Asteroid,
Comet SECTION B
1. (a) (i) Meteor
Formatif 1 1
HOTS Challenge (ii) Meteoroid
Pr
(b) (ii) and (iii)
Asteroid, because the size of the asteroid
is bigger than the meteoroid. Therefore, SECTION C
its impact is greater. 1. (a) Meteoroid
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