Focus PT3 2022 - Science

PELANGI BESTSELLER

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.SCIENCEPT3
FORM

1∙2∙3

KSSM

Maznah Omar (Textbook Writer) D ual L anguage
Jariah Khalib (Textbook Writer) P rogramme
Badariah Hamzah (Textbook Writer)
Chien Hui Siong
Tan Din Ding

CONTENTS

FORM 1 THEME 3 Exploration of Elements in Nature

THEME 1 Scientific Methodology 5Chapter Matter 85
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
1Chapter Introduction to Scientific 1 5.1 Matter in Nature 86
Investigation 5.2 Three States of Matter 90
PT3 Practice 5 98
1.1 Science is Part of Daily Life 2 100
1.2 Your Science Laboratory 4
1.3 Physical Quantities and Their Units 7 6Chapter
1.4 The Use of Measuring Instruments, Accuracy, Periodic Table

Consistency, Sensitivity and Errors 9
1.5 Density 18
1.6 Steps in a Scientific Investigation 22 6.1 Classification of Elements 101
1.7 Scientific Attitudes and Values in Carrying Out 6.2 Mixtures 109
Scientific Investigation 25 6.3 Compounds 115
PT3 Practice 1 26 PT3 Practice 6 120
121
7Chapter Air

Maintenance and Continuity of 7.1 Composition of Air 122
THEME 2 Life 7.2 Combustion 126
7.3 Air Pollution 130
2Chapter Cell as the Basic Unit of Life 28 PT3 Practice 7 132

2.1 Cell – Structure, Function and Organisation 29 THEME 4 Energy and Sustainability of Life
2.2 Cellular Respiration and Photosynthesis 38
PT3 Practice 2 44 8Chapter Light and Optics 134

3Chapter Coordination and Response 45 8.1 The Use of Mirrors 135
8.2 Properties of Light 141
3.1 Homeostasis in Living Things 46 8.3 Reflection of Light 142
PT3 Practice 3 54 8.4 Refraction of Light 144
8.5 Dispersion of Light 148
8.6 Scattering of Light 151
8.7 Addition and Subtraction of Light 153
PT3 Practice 8 159

4Chapter Reproduction 55 THEME 5 Exploration of Earth and Space

4.1 Sexual and Asexual Reproduction 56 9Chapter Earth 161
4.2 Human Reproductive System 61
4.3 The Menstrual Cycle 65 9.1 The System and Structure of the Earth 162
4.4 Fertilisation and Pregnancy 67 9.2 Composition of the Earth 166
4.5 Factors Affecting the Development of a 70 9.3 Main Processes of the Earth 168
71 9.4 Geohazard Phenomena 170
Foetus and Baby 74 9.5 Age of the Earth 176
4.6 Infertility and Contraception 82 9.6 Earth Resources and Applied Geology 179
4.7 Plant Reproduction PT3 Practice 9 184
PT3 Practice 4

ii

FORM 2 THEME 3 Energy and Sustainability of Life

THEME 1 Maintenance and Continuity of 7Chapter
Life

1Chapter Electricity and Magnetism 274

Biodiversity 185 7.1 Electricity 275

7.2 Flow of Electric Current in Series Circuit and 284
Parallel Circuit
1.1 Diversity of Organisms 186 7.3 Magnetism 289
1.2 Classification of Organisms 189 PT3 Practice 7 295
196
PT3 Practice 1
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. 8Chapter
2Chapter Ecosystem 198 Force and Motion 297

2.1 Energy Flow in Ecosystem 199 8.1 Force 298
2.2 Nutrient Cycle in Ecosystem 201 8.2 Effects of Force 301
2.3 Interdependence and Interaction Among 312
203 PT3 Practice 8
Organisms and between Organisms and 211
the Environment 212 9Chapter Heat 314
2.4 Role of Human in Maintaining a Balanced
Nature 9.1 Relationship between Temperature and Heat 315
9.2 Heat Flow and Thermal Equilibrium 317
PT3 Practice 2

3Chapter 9.3 Principle of Expansion and Contraction of
Matter 323
Nutrition 214 9.4 Relationship between Types of Surface of

3.1 Classes of Food 215 Object, and Heat Absorption and Emission 328
3.2 Importance of a Balanced Diet 220 PT3 Practice 9 332
3.3 Human Digestive System 223
3.4 Process of Absorption and Transportation 227 1 0Chapter Sound Waves 334
of Digested Food and Defecation 230
10.1 Characteristics of Sound Waves 335
PT3 Practice 3 10.2 Loudness and Pitch of Sound 339
10.3 Phenomena and Applications of Reflection 342
4Chapter Human Health 232 of Sound Waves 344

4.1 Infectious and Non-infectious Disease 233 PT3 Practice 10
4.2 Body Defence 236
241 THEME 4 Earth and Space Exploration
PT3 Practice 4

THEME 2 Exploration of Elements in Nature 1 1Chapter Stars and Galaxies in the
Universe 345

5Chapter 11.1 Star and Galaxies in the Universe 346
PT3 Practice 11 352
353
Water and Solution 243 1 2Chapter

5.1 Physical Characteristics of Water 244 Solar System
5.2 Solution and Rate of Solubility 251
5.3 Water Purification and Water Supply 256 12.1 Solar System 354
259 PT3 Practice 12 363
PT3 Practice 5 364
261
6Chapter Acids and Alkalis 262 1 3Chapter Meteoroid, Asteroid, Comet
270
6.1 Properties of Acids and Alkalis 273 13.1 Other Objects in the Solar System; such 365
6.2 Neutralisation as Meteoroids, Asteroids and Comets 370

PT3 Practice 6 PT3 Practice 13

iii

FORM 3 THEME 3 Energy and Sustainability of Life

Maintenance and Continuity of 6Chapter
THEME 1 Life

1Chapter Electricity and Magnetism 458

Stimuli and Responses 371 6.1 Generation of Electricity 459

6.2 Transformer 464
6.3 Transmission and Distribution of Electricity 468
1.1 Human Nervous System 372
1.2 Stimuli and Responses in Humans 374
1.3 Stimuli and Responses in Plant 384
1.4 Importance of Responses to Stimuli 389
in Animals 391

PT3 Practice 1
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. 6.4 Calculate the Cost of Electricity Consumption 476
PT3 Practice 6 480

7Chapter Energy and Power 482

2Chapter Respiration 394 7.1 Work, Energy and Power 483
7.2 Potential Energy and Kinetic Energy 486
2.1 Human Respiratory System 395 7.3 Principle of Conservation of Energy 490
2.2 Movement and Exchange of Gases in the 400 492
Human Body 402 PT3 Practice 7
2.3 Health of Human Respiratory System 405
2.4 Adaptations in Respiratory Systems 408 8Chapter Radioactivity 494
2.5 Gaseous Exchange in Plants 411

PT3 Practice 2

3Chapter 8.1 Discovery of Radioactivity 495
8.2 Atom and Nucleus 499
Transportation 413 8.3 Ionising Radiation and Non-ionising Radiation 500

8.4 Uses of Radioactive Radiation 506
PT3 Practice 8 509
3.1 Transport System in Organisms 414
3.2 Blood Circulatory System 414
3.3 Human Blood 420
3.4 Transport System in Plants 423
3.5 Blood Circulatory System in Animals and
Transport System in Plants 431 THEME 4 Earth and Space Exploration

PT3 Practice 3 432 9Chapter

THEME 2 Exploration of Elements in Nature Space Weather 511

4Chapter Reactivity of Metals 434 9.1 Activities of the Sun that Affect Earth 512
9.2 Space Weather 517
519
PT3 Practice 9

4.1 Variety of Minerals 435 1 0Chapter Space Exploration 521
4.2 Reactivity Series of Metals 439
4.3 Extraction of Metals from Its Ore 444 10.1 Development in Astronomy 522
447 10.2 Development of Technology and its 523
PT3 Practice 4 Application in Space Exploration 529

5Chapter Thermochemistry 449 PT3 Practice 10

5.1 Endothermic and Exothermic Reactions 450 https://plus.pelangibooks.com/
PT3 Practice 5 456 Resources/Focus2022/PT3/Science/
PT3 Model Paper PT3ModelPaper&Answers.pdf 530

ANSWERS 531

iv

2Chapter Theme 2: Maintenance and Continuity of Life
Form 1

Pengenalan kepada
PCeenlyl iaassathtaenBSaasiinctUifnikit of Life

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.Made up of many cellsMulticellular organismsSystems

Unicellular organisms form Cells form Tissues Organs
Made up of single cell
are

Basic unit of life

Animal cell similarities Plant cell
have
has cell wall,
chloroplasts and

a large vacuole

Cell respiration Nucleus, cell membrane, Photosynthesis
occurs in cytoplasm and mitochondria
mitochondria occurs in chloroplasts

Produces energy by Makes food from carbon dioxide
breaking down food. and water in the presence of
chlorophyll and sunlight.
28

2.1 Cell – Structure, Function and   Science PT3  Chapter 2  Cell as the Basic Unit of Life 
Organisation
5. When a cell divides rapidly without control,
it can form a tumour or cancer.

What is a Cell? Form
Form

A cell is the basic unit that makes up all Normal Cell division 1
living things. cell Cancer cell

1. Cells are too small that they cannot be seenPenerbitan Pelangi Sdn Bhd. All Rights Reserved.

with the naked eye; they can only be clearly
seen under a microscope.



Cell size and scale Normal cell division
stops
INFO

SCIENCE IINNFFOO Uncontrolled continuous
cancer cell division
An English scientist, Robert Hooke was the
first person to discover cells. He was observing Figure 2.2 Normal cell and cancer cell division
a slice of cork under a simple microscope
made by him when he found the cork consisted 6. If not destroyed, cancer cells will divide
of an arrangement of small units which were uncontrollably to form a tumour, an
separated by walls. He named these small units abnormal lump of cells.
as cells, which means small rooms in Latin.
Formation of tumour
2. Cells carry out life processes like respiration,
growth, reproduction and excretion. Cancer cell Normal cell
division
3. Cells also undergo cell division, a process by
which a single cell divides into two or more Figure 2.3 The formation of tumour
cells.
7. Tumours can destroy surrounding cells.
Figure 2.1 Cell division
8. A tumour can invade surrounding cells and
4. Cell division is essential for the growth of spread from one part of the body to another
living things and in producing new cells to which then leads to the malfunctions of the
replace damaged or dead cells. body parts. This is called cancer.

29

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

The Structure of Animal Cells and Plant Cells

1. Cells are very tiny and can only be clearly seen under a microscope.

Form
Form
2. A microscope is used to observe the structure of animal and plant cells in Activities 2.1 and 2.2.

1 Eyepiece magnifies the image of the specimen Steps
to about ten times (10x) magnification.
1 Place the microscope in
Tube connects the eyepiece to the objective a bright place.
lenses.
2 Crank the low power
Coarse focus knob is used to move the objective lens down so
low power objective lens. that it is clicked into
position.
Fine focus knob is used to move the
high power objective lens to bring the
specimen into better focus.
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Low power objective lens 3 Adjust the diaphragm
magnifies the image of the and mirror so that there
specimen to 4x. is sufficient light to view
the specimen through
Medium power objective the microscope.
lens magnifies the image
of the specimen to 10x. 4 Place the slide on the
stage and use the clips
High power to hold the slide.
objective lens
magnifies the image 5 Turn the coarse focus
of the specimen to knob to lower the body
40x. tube as close to the
specimen as possible
Diaphragm controls without touching it.
the amount of light
that enters the 6 Look through the
condenser and the eyepiece, and turn
condenser focuses the coarse focus knob
light from the mirror anticlockwise to move
onto the specimen. the body tube up until
the image comes into
Mirror reflects focus.
light towards
the diaphragm. 7 Turn the fine focus
knob for fine focusing.
Stage is the
platform to place the
slides.

Clips hold the slides
in place.

Figure 2.4 The structure of a microscope and the way to use it

30

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

EkAscpteivriimtye2n.12.1

Aim: To prepare an animal cell slide and to examine animal cells Form
(human cheek cells). Form
Materials and apparatus: Methylene blue solution, distilled water,
toothpick, filter papers, glass slide, cover slip, light microscope, dropper, 1
mounting needle and forceps.
Procedure:
1. A drop of distilled water is placed on the centre of a clean slide.
2. The blunt end of a toothpick is used to gently scrape the inner

lining of the cheek.
3. The scrapings are placed in the middle of the water drop on the

slide.
4. A cover slip is lowered slowly on the specimen using a mounting

needle to ensure that air bubbles are not trapped under the cover
slip.
5. A drop of methylene blue solution is placed on one edge of the
cover slip and a piece of filter paper is placed on the other edge of
the cover slip. The filter paper will draw the methylene blue solution
across the slide to stain the cells.
6. Excess methylene solution is absorbed using another piece of filter
paper.
7. The slide is observed under the low power objective lens of the
light microscope, followed by the high power objective lens.
8. The structure of the cheek cells is drawn and labelled accordingly.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Distilled Toothpick
water
Cheek Mounting
scrapings needle

Cover slip

Observations: Methylene Filter
blue solution paper

Cytoplasm Figure 2.5 Preparing the slide of
human cheek cells

Cell membrane TIMSS Challenge 1
Nucleus
Why do we need to add a drop of
Figure 2.6 Human cheek cells methylene blue solution onto the
cheek cells when preparing the
slide of cheek cells?

Discussions: Common Error

1. Methylene blue solution stains the cheek cell, so that the All living things
structure of the cell can be seen clearly. contain cells.

2. Human cheek cells do not have a fixed shape. All living things are
3. The structures of the human cheek cells as seen under the light made up of cells.

microscope are the nucleus, cell membrane and cytoplasm.

Conclusion:
An animal cell does not have a fixed shape, and has a nucleus, cell membrane and cytoplasm.

31

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

EkAscpteivriimtye2n.2.1Form Onion
Form scale
Aim: To prepare a plant cell slide and to examine plant cells (epidermal Epidermal layer of onion
cells of an onion bulb)
Epidermal layer
Materials and apparatus: Onion bulb, iodine solution, distilled water, of onion

1 filter papers, glass slide, cover slip, light microscope, dropper, mounting Mounting
needle, scalpel and forceps. needle
Cover slip
Procedure:
1. A drop of distilled water is placed on the centre of a clean slide.
2. An onion scale is cut using a scalpel and an epidermal layer from it

is peeled off using a forceps.
3. The epidermal layer is then placed in the middle of the water drop on

the slide.
4. A cover slip is lowered slowly on the specimen using a mounting needle

to ensure that air bubbles are not trapped under the cover slip.
5. A drop of iodine solution is placed on one edge of the cover slip and

a filter paper is held at the other edge of the cover slip to draw the
iodine solution across the slide to stain the cells.
6. Excess iodine solution is absorbed using another piece of filter paper.
7. The slide is observed under the low power objective lens of the light
microscope, followed by the high power objective lens.
8. The structure of the epidermal cells is drawn and labelled
accordingly.
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Observations: Figure 2.7 Preparing the
slide of epidermal cells
Membrane cell
Cell wall Tips

Nucleus Methylene blue solution is
Cytoplasm usually used to stain animal
Vacuole cells, while iodine solution is
used to stain plant cells.

Figure 2.8 Epidermal cells of an onion bulb

Discussion: TIMSS Challenge 2

1. Iodine solution stains the nucleus brown so that the structure of Name two structures that can
epidermal cells can be seen clearly.
only be found in plant cells but
2. Epidermal cells of onion bulb have a fixed shape.
3. The structures of the epidermal cells as seen under the light not in animal cells. PAK-21

microscope are the cell wall, cell membrane, nucleus, cytoplasm
and vacuole.

4. Onion cells do not contain chloroplasts. Only plant cells that carry out photosynthesis have chloroplasts.

Conclusion:
A plant cell has a fixed shape, a nucleus, cell membrane, cytoplasm, cell wall and vacuole.

32

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

Functions of Structures in Animal Cells and Common Error
Plant Cells

1. There are many similarities and differences between Form
animal cells and plant cells. Form
All plant cells contain chloroplasts.
2. Both cells have a nucleus, cytoplasm, cell membrane Not all plant cells have 1
and mitochondria.
chloroplasts. For example, the
3. Plant cells have additional structures, namely cell wall, epidermal cells of an onion
chloroplasts and vacuole. bulb which do not carry out
photosynthesis do not contain
chloroplasts.
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4. Each cell structure has a specific function.

Cell membrane
• A thin layer which forms the external boundary of the cell.
• Controls the movement of materials in and out of the cell.

Nucleus

• Oval or spherical in shape.
• Controls all activities of the cell.
• Contains chromosomes that are made up of deoxyribonucleic acid (DNA) which

carries genetic information that determines the characteristics of an organism.

Cytoplasm

• A jelly-like substance.
• As a medium where chemical processes occur.

Mitochondrion

• Cylindrical-shaped.
• The site of cellular respiration to generate energy.

The difference Animal cell
between animal
Plant cell
VIDEO and plant cells

Vacuole Cell wall Chloroplast
• A fluid-filled sac containing • An outer layer which • Contains a green

cell sap. surrounds the cell pigment called
• Absorbs water and keeps membrane of a plant cell. chlorophyll that
• Provides support and helps absorbs sunlight
the cell turgid. This turgidity protect the cell, and gives for the process of
provides support to the cell. a fixed shape to the cell. photosynthesis in
green plants.
Figure 2.9 Functions of animal and plant cell structures
33

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

Comparison between Animal Cells and Plant Cells

Form Animal cell Plant cell
Form
Similarities Icon Focus KSSM Science form 1 English ver.

Both have a nucleus, cell membrane, cytoplasm and mitochondria

1 Differences
Cell wall
Does not have a cell wall
Does not have chloroplast Chloroplast
Usually absent, but if present, the vacuoles
Vacuole
are small and scattered
Does not have a fixed shape Shape
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Has a cell wall made of cellulose
Has chloroplasts that containPcluhrlaolrophyll

Has one or a few large vacuoles

Has a fixed shape

Figure 2.10 Similarities and differences between animal cells and plant cells

Unicellular and Multicellular Organisms Singular PPlluurraall
Mitochondrion Mitochondria
Unicellular organisms
Multicellular organisms

Unicellular organisms are organisms that Multicellular organisms are organisms that
consist of only one cell. consist of more than one cell.

• Although consisting of only one cell, unicellular • Humans, animals and plants are examples of
organisms are able to perform all living processes multicellular organisms.
within a single cell - they can move, feed, reproduce,
grow, respond to stimuli, excrete and respire. • Multicellular organisms are made up of many
types of cells which differ in terms of structure and
• Unicellular organisms are also known as function.
microorganisms because of their tiny size and can
only be seen under a microscope. • Some multicellular organisms are microorganisms
that are very tiny and cannot be seen clearly by the
• Amoeba and Paramecium are unicellular naked eye.
animals, whereas yeast and Chlamydomonas are
unicellular plants.

• Euglena can be classified as a plant because it can
make its own food in the presence of sunlight.

• Euglena can also be classified as an animal
because it can feed and move by using flagella.

Hydra Spirogyra Mucor

Figure 2.12 Multicellular microorganisms

Paramecium Chlamydomonas • Most multicellular organisms are bigger in size and
complex compared to unicellular organisms.
Euglena Amoeba
• Mammals, reptiles, amphibians, birds and fish are
examples of multicellular animals.

• Algae, ferns and most of the flowering plants are
examples of multicellular plants.

Figure 2.11 Unicellular organisms

34

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

The Types and Functions of Animal Cells and Plant Cells

1. Humans, animals and plants are multicellular organisms in SCIENCE IINNFFOO Form
large size, and they are made up of different types of cells for Form
various life processes. Humans are made up of
more than 50 trillion 1
2. These cells have different shapes and structures to carry out (50 000 000 000 000) cells.
different functions. They are called specialised cells.

Specialised cells are cells that have become differentiated to carry out a particular function.Penerbitan Pelangi Sdn Bhd. All Rights Reserved.

3. Figures 2.13 and 2.14 show various types of specialised cells in humans and plants with their
special features and functions.

Nerve cells Epithelial cells
• Also known as neurons.
• Have long, thin fibres. • Epithelial cells that Cilia
• Carry information in the form line the trachea

of nerve impulses to different (respiratory tract)
parts of the body.
have a thin layer of
Red blood cells
• Have biconcave disc tiny moving ‘hairs’

shape which provides called cilia.
a large surface area.
• Contain no nucleus. • Cover the outer surface of the
• Contain haemoglobins (red
pigments) which combine with body and line the surfaces of
oxygen.
• Transport oxygen from the lungs organs.
to the whole body, and transport
carbon dioxide from the body cells White blood cells
back to the lungs which is then • Do not have a fixed
expelled during exhalation.
shape.
Muscle cells • Destroy bacteria that
• Muscle cells along
enter the body and
the wall of intestine protect the body against
(digestive system) are diseases.
elongated cells, whereas
muscle cells in the heart Reproductive cells
(cardiac muscle) have a • Sperm cell is the male
branched shape.
• Muscle cells contract reproductive cell that has a
and relax to produce long tail which allows it to swim
movements of various towards the egg cell (ovum),
body parts. the female reproductive cell.
• Sperm contains genetic
information from the father,
whereas ovum contains genetic
information from the mother.

Sperm Ovum
Figure 2.13 Various types of specialised cells in humans and their functions

35

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

Epidermal cells Cuticle layer Palisade cells
• Epidermal cells are flat and
• Contain lots of Cell wall
have a large vacuole. chloroplasts which Chloroplast
Form contain chlorophyll.
Form Vacuole
• Coated by a waxy cuticle layer • Absorb sunlight to Cytoplasm
carry out photosynthesis. Nucleus
on top, this reduces water loss.

• Epidermal cells are transparent

1 to allow light to penetrate the
cell for photosynthesis.

Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Plant cells

Root hair cells Guard cells A pair of guard cells

• Have a long thin extension, Root hair • Kidney-shaped cells. Chloroplast
the root hair which provides • Two guard cells surround Stoma
a large surface area for an opening called stoma.
absorption of water and • Guard cells help to regulate
nutrients from the soil. gas exchange by opening
and closing the stoma.

Figure 2.14 Various types of specialised cells in plants and their functions

Formation of an Organism

1. Cells in multicellular organisms are 4. Several specialised organs work together
organised to form tissues, organs and to form a system which performs a major
systems which all together form an function.
organism.
5. All the systems combine to make up what
2. Cells of the same structure that carry out a is known as a multicellular organism.
similar function make up a tissue.

3. A group of different tissues that work
together to perform a particular function
forms an organ.

HPOraTkStisCFhoramllaetnifg1e 1 Human

• Evaluating Multicellular
Is blood a cell or a tissue? Why? organism

Muscle tissue Stomach Digestive system All the systems
combine to form
Tissue Organ System
A group of Two or more Several organs a multicellular
specialised cells types of tissues work together to organism.
with a similar work together to perform a major
function. perform a particular
function.
function.
Muscle cell
Figure 2.15 Cell organisation in a
Cell multicellular organism
Basic unit of life.

36

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

Systems in the Human Body
1. There are various systems in the human body that work together to carry out different

functions.
2. All these systems are coordinated to form a complete life.
Form
Respiratory system Digestive system Form
Blood circulatory Excretory system
system Nose Mouth 1
Trachea Oesophagus Lung
Heart Lung Liver Kidney
Blood Stomach Ureter
vessels Small intestine
Large intestine Urinary
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. bladder
Transports respiratory Absorbs oxygen and Breaks down complex
gases, nutrients, releases carbon dioxide. food into smaller form so Skin
that the nutrients can be
hormones and waste Muscular system easily absorbed into the Removes excretory
products. products such as urea
body. and uric acid from the
Integumentary system
Skeletal system body.
Skin
Skull Lymphatic system

Muscles Thymus gland
Lymph

Bone Lymph node

Lymphatic
vessels

Made up of human Assists humans in Provides support to Defends the body
skin that protects the movement. the body and protects against infections.
body from infection and internal organs such as
keeps the body from Endocrine system
losing water excessively lungs and brain.
Pituitary gland
(dehydration). Thyroid gland Reproductive system
Adrenal gland
Nervous system Pancreas Uterus
Ovary (female) Vagina
Brain Testis (male) Ovary

Spinal cord

Nerves

Testis
Penis

Carries information in the Secretes hormones to The male reproductive system produces sperm and
form of nerve impulses coordinate the body male sex hormones while the female reproductive
and coordinates all the activities together with system produces ovum and female sex hormones for
body activities. the nervous system.
the formulation of offspring.

37

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 2.2 Cell Respiration and
Photosynthesis
Appreciating the Existence of
Various OrganismsForm Cell Respiration
Form
1. We should appreciate the existence of wide 1. We require energy to carry out various
variety of organisms on Earth as a sign of activities and living processes.
the glory of God.
2. The energy is obtained from the food we
1 2. Various organisms live together, interact and take.
depend on one another for their survival.

3. Organisms also interact with the
environment to create a balanced
ecosystem.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. 3. Our body cells are able to break down the
food to release energy stored in it. This is
called cellular respiration.

Formative Practice 2.1 4. The process of breaking down food to
release energy is called respiration.

1. Arrange the steps in preparing a plant cell slide Respiration is the process of producing
in the correct sequence. energy throguh the breakdown of food
molecules.
( ) The slide is observed under the
microscope. 5. Respiration can be divided into two stages:
(a) External respiration or breathing
( ) A thin epidermal layer is peeled off from (b) Internal respiration or cell respiration
the onion.
External respiration (breathing) is the
( ) The specimen is covered with a cover exchange of oxygen and carbon dioxide
slip using a mounting needle. between an organism and its environment.

( ) A drop of iodine solution is added to the
slide to stain the structures of the cell.

( ) The epidermal layer is placed on a slide
in a drop of water.

2. Match the human cells to their functions.
Nerve cells ► ◄ Involved in reproduction
Sperm cells ► ◄ Allow body movement

Muscle cells► ◄ Transport oxygen Internal respiration (cell respiration) is
the oxidation and breakdown of glucose
Red blood ► ◄ Receive and send nerve that occur in the living cells to release
cells impulses energy.

3. State three differences between animal cells
and plant cells.

4. What is meant by unicellular organisms and 6. Cell respiration uses oxygen we breathe
multicellular organisms? in and glucose from the food to release
energy.
HPOraTkStisCFhoramllaetnifg1e 2
7. Carbon dioxide and water are formed as
• Evaluating by-products during cell respiration.

Predict what will happen to the number 8. Cell respiration can be defined as the
process that needs oxygen and glucose to
of white blood cells produced if we are release energy, carbon dioxide and water.

attacked by the flu. State an inference to your C6H12O6 + 6O2 → 6CO2 + 6H2O + 2898 kJ
Glucose Oxygen Carbon Water Energy
prediction.
dioxide

38

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

Photosynthesis Leaf Boiling FormEthanol
water Form Hot water
1. Green plants are able to make their own
food through the process of photosynthesis. A leaf is immersed Bunsen burner 1
into a beaker of (turned off)
Photosynthesis is the process by which boiling water for a
green plants make food from carbon few minutes to break The leaf is placed
dioxide and water in the presence of light down the cell walls into a boiling
and chlorophyll. and soften the leaf. tube containing
ethanol which is
2. Chloroplasts are the cell structures involved then placed into a
in photosynthesis and contain chlorophyll beaker of hot water
that absorbs sunlight. for a few minutes
to decolourise the
3. Green plants use carbon dioxide and leaf (to remove
water in the presence of sunlight and chlorophyll).
chlorophyll to make food in the form of
glucose. Oxygen is released as the by-
product of photosynthesis.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
Sunlight Carbon dioxide Hot Iodine
is absorbed water solution
Chlorophyll
Glucose is The decolourised tWilehite
produced leaf is then dipped
into a beaker of The leaf is placed
Oxygen is released hot water for a few on a white tile. A
seconds to soften few drops of iodine
Water is absorbed the leaf and to get solution are added
by roots the ethanol off the on to the leaf to test
leaf. for starch.

Figure 2.16 The process of photosynthesis Figure 2.17 Steps involved in the iodine test for starch

4. The whole process of photosynthesis can be 7. The presence of starch in the leaf can be
summarised by the following equation: tested using iodine solution after removing
the chlorophyll using an alcohol.
6H2O + 6CO2 Sunlight C6H12O6 + 6O2
Water Carbon Chlorophyll Glucose Oxygen 8. Starch is present if the brown colour of
iodine solution turns blue-black.
dioxide
9. Experiments 2.1 – 2.4 are carried out to
5. Excess glucose is stored in the form of show the factors required for photosynthesis
starch in leaves, stems, fruits and roots. such as light, carbon dioxide, chlorophyll
and water.
6. We can determine whether photosynthesis
has taken place in a plant by testing the Photosynthesis
presence of starch in the leaf using the VIDEO
iodine test.

39

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

pEkxsppeerirmimeennt 2.1

Problem statement: Does photosynthesis require sunlight?Form
Hypothesis: Sunlight is essential for photosynthesis.Form
Aim: To investigate whether sunlight is essential for photosynthesis.

1 Manipulated variable: The presence of sunlight
Responding variable: The colour change of iodine on the leaf
Constant variable: Type of plants
Materials and apparatus: Two similar potted green plants, boiling tube, beaker,
Bunsen burner, tripod stand, wire gauze, forceps, dropper, white tile, ethanol, iodine
solution and hot water.
Procedure:
1. Two similar potted plants are prepared and labelled as plant K and plant L.
2. Plant K is exposed to sunlight whereas plant L is kept in the dark.
3. After one week, a leaf is plucked from each plant and then tested for the presence
of starch.

Observations:
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Plant K
(In the dark)

Plant L
Figure 2.18

Leaf Presence of Observation for Inference
Plant K sunlight the test for starch
Plant L Yes Photosynthesis takes place in the presence of
The leaf turns sunlight.
No blue-black Photosynthesis does not take place in the dark
(absence of sunlight).
No change

Discussion:

1. Starch is present in the leaf of plant K that is exposed to the sunlight whereas starch is absent in the leaf
of plant L that is not exposed to the sunlight.

2. Plant L does not receive sunlight, therefore photosynthesis does not take place.

Conclusion:
The hypothesis is accepted. Sunlight is essential for photosynthesis.

Ekxsppeerirmimeennt 2.12

Problem statement: Does photosynthesis require carbon dioxide?
Hypothesis: Carbon dioxide is essential for photosynthesis.
Aim: To investigate whether carbon dioxide is essential for photosynthesis.
Manipulated variable: The presence of carbon dioxide
Responding variable: The colour change of iodine on the leaf
Constant variable: Type of plants
Materials and apparatus: Two similar potted green plants, bell jars, glass plates coated with vaseline, beaker,
boiling tube, white tile, Bunsen burner, tripod stand, wire gauze, forceps, dropper, ethanol, hot water, iodine
solution and potassium hydroxide solution.
Procedure:
1. Two potted plants are kept in a dark place for two days to remove the starch.
2. The apparatus is set up as shown in Figure 2.19 and kept under the Sun.

40

Sunlight   Science PT3  Chapter 2  Cell as the Basic Unit of Life 
Sunlight

Air without Air Form
carbon dioxide Form
Bell jar

1

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.Potassium hydroxide solution

Green plant M Glass plates with vaseline Green plant N

Figure 2.19 The set-up of apparatus

3. After a few days, the leaves from both plants are tested for the presence of starch.

Observations:

Leaf Presence of Observation for the Inference
Plant M carbon dioxide test for starch
Plant N Photosynthesis does not take place in the
No No change absence of carbon dioxide.
Photosynthesis takes place in the presence of
Yes The leaf turns carbon dioxide.
blue-black

Discussion:

1. No starch is formed in the leaf of plant M which is exposed to the air without carbon dioxide.
2. Potassium hydroxide solution absorbs carbon dioxide inside the bell jar.
Conclusion:

The hypothesis is accepted. Carbon dioxide is essential for photosynthesis.

Ekxsppeerirmimeennt 2.31

Problem statement: Does photosynthesis require chlorophyll? Figure 2.20 Variegated leaves
Hypothesis: Chlorophyll is essential for photosynthesis.
Aim: To investigate whether chlorophyll is essential for photosynthesis.
Manipulated variable: The presence of chlorophyll
Responding variable: The colour change of iodine on the leaf
Constant variable: Type of plants
Materials and apparatus: A variegated leaf, beaker, boiling tube, white
tile, Bunsen burner, tripod stand, wire gauze, forceps, dropper, ethanol, hot
water and iodine solution.
Procedure:
1. A variegated leaf is plucked from a plant which has been exposed to

the sunlight for several hours.
2. A sketch to show the green and non-green colour distributions on the

leaf is drawn.
3. The leaf is tested for the presence of starch.
4. The observations are recorded.

41

  Science PT3  Chapter 2  Cell as the Basic Unit of Life

Observations:

Green Blue-black
region (starch is present)

Form White Brown
Form region (starch is absent)

Figure 2.21 Sketches of the variegated leaf before and after the test for starch

1 Discussion:

1. A variegated leaf is a leaf with different colours (pigments) on it.
2. Starch is present only in the green region of the leaf that contains chlorophyll.
3. No starch is formed in the non-green region of the leaf due to the absence of chlorophyll.
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Conclusion:
The hypothesis is accepted. Chlorophyll is essential for photosynthesis.

Ekxsppeerirmimeennt 2.41

Problem statement: Does photosynthesis require water? Plant P Plant Q
Hypothesis: Water is essential for photosynthesis.
Aim: To investigate whether water is essential for photosynthesis. Figure 2.22 The set-up of
Manipulated variable: The presence of water apparatus
Responding variable: The colour change of iodine on the leaf
Constant variable: Type of plants
Materials and apparatus: Two similar potted green plants, water,
boiling tube, white tile, Bunsen burner, tripod stand, wire gauze, forceps,
dropper, ethanol, hot water and iodine solution.

Procedure:

1. Two similar potted green plants are exposed to sunlight.
2. Plant P is watered every day whereas plant Q is not watered.
3. After one week, a leaf is plucked from each plant and then tested for the presence of starch.

Observations:

Leaf Presence of Observation for the Inference
Plant P water test for starch
Plant Q Yes The leaf turns Photosynthesis takes place in the presence of
blue-black water.
No Photosynthesis does not take place in the
No change absence of water.

Discussion:
Starch is present in the leaf of plant P that is watered every day whereas starch is absent in the leaf of plant Q
that is not watered.

Conclusion:
The hypothesis is accepted. Water is essential for photosynthesis.

42

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 

The Differences between Cell Respiration and Photosynthesis

1. Cell respiration and photosynthesis Form
are opposite processes that Form
complement each other in the

environment.

2. Photosynthesis by green plants Light energy Photosynthesis occurs 1
produces food (glucose) for other is absorbed in the chloroplast of
organisms and releases oxygen
into the atmosphere. Glucose plant cells
+
3. The oxygen and glucose produced
are used by other organisms for Oxygen
cell respiration to obtain energy.

4. Cell respiration releases carbon
dioxide which is used by green
plants to carry out photosynthesis,
and this cycle continues.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Chloroplast Carbon dioxide
+

Water

5. Therefore, both processes of Mitochondrion Cell respiration occurs
photosynthesis and cell respiration in the mitochondrion of
are important and complement Energy is released ATP
each other for living cells of all organisms

(a) the survival of living things.

(b) maintaining the balance of
oxygen and carbon dioxide in
the atmosphere.

Figure 2.23 Relationship between photosynthesis and
cell respiration

Table 2.1 Differences between cell respiration and photosynthesis Formative Practice 2.2

Cell respiration Photosynthesis 1. Why do we test for the presence
Occurs in all living cells. Occurs in all plant cells that of starch to determine if
photosynthesis has occurred?
contain chlorophyll.
2. Based on the figure below,
Process of breaking down Process of making food answer the following questions.
food (glucose). (glucose). (a) What are processes X and Y?
(b) What are the purposes of
Takes place in mitochondria. Takes place in chloroplasts. processes X and Y?
(c) Which process also occurs in
Carbon dioxide and water are Carbon dioxide and water animal cells?

released. are used. Carbon dioxide Process X
Oxygen (day)

Oxygen is used. Oxygen is released. Light

Occurs all the time (day and Occurs only in the presence Carbohydrates
Water

night). of light. Energy

Energy is released during the Light energy is absorbed to Oxygen Process Y

breakdown of food. make food. Water Carbon dioxide (day and night)

43

  Science PT3  Chapter 2  Cell as the Basic Unit of Life 2

PT3 Practice

Form
Form
SECTION A
A Glucose + Oxygen → Carbon dioxide + Water
1 1. The following statement describes the + Energy
characteristics of cell P.
B Water + Carbon dioxide → Glucose + Oxygen
•  No cell wall + Energy
•  No nucleus
C Oxygen + Water → Carbon dioxide + Glucose
Which of the following is cell P? + Energy
A Nerve cell
B Palisade cell D Energy + Oxygen → Glucose + Carbon dioxide
C Red blood cell
D Onion epidermis cell 3. Which of the following is the importance of
photosynthesis and cell respiration process?
2. Cell respiration is the energy generating process. A To preserve the balance of oxygen and carbon
Which of the following is the correct word dioxide content in the atmosphere.
equation for the cell respiration process? B To preserve the balance of nitrogen in the
atmosphere.
C To maintain the cleanliness of the environment.
D To avoid the increase in global temperature.
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SECTION B

1. (a) Figure 1 shows two types of cells. Name the cells.
(i) (ii)

Figure 1 [2 marks]
[2 marks]
(b) Underline the correct statements regarding the photosynthesis.
(i) Carbon dioxide and water are (used / produced) in the process of photosynthesis.
(ii) Light energy is (absorbed / released) to synthesise food molecules.

SECTION C

1. Teacher Ali showed a video about the process of photosynthesis and its importance to the students in class
1 Arif. The following statement is one of the quotes in the video:

Photosynthesis is the food-making process by green plants from water and carbon dioxide with the
presence of light and chlorophyll.

(a) State the word equation for the process of photosynthesis. [3 marks]

(b) Carbon dioxide is a substance that is required in the process of photosynthesis. [1 mark]
From where do plants get this supply of carbon dioxide? [2 marks]
(c) State two importance of the process of photosynthesis. [2 marks]
(d) State how deforestation interrupts the process of photosynthesis.

44

5Chapter Theme 2: Exploration of Elements in Nature
Form 2

Water and Solution

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.Dilute solutionTypesFactors thatTemperature of the
Concentrated solution affect the solvent

Solution Stirring rate

Saturated solution Size of the solute

Water and Solution

Water

Physical Evaporation Water purification and supply
characteristics Influencing factors
Water purification Water
Boiling point Surrounding method sustainability
temperature
Freezing Filtration Water supply
point Humidity Boiling system
Chlorination
Colour Exposed
surface of
Density
water
Distillation
Air movement

243

  Science PT3  Chapter 5  Water and Solution SCIENCE IINNFFOO

5.1 Physical Characteristics of Water • Cohesive forces is the attractive forces
between similar molecules.
1. Water is a very important source for nature
and human beings. • Adhesive force are the attractive forces
between different molecule.
2. Water is an important medium for
physiological functions; regulates the 6. Water exists in three forms, they are solid,
body temperature and performs excretory liquid and gas.
functions in the human body.
7. The changes to the forms of water is caused
3. Pure water has the following unique by the absorption and release of heat from
characteristics. They are: the surroundings. Figure 5.3 shows the
(a) colourless effects of absorption and release of heat
(b) odourless (no smell) on water.
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Form(d) exist in liquid form at room Melting Desublimation
Form temperature
(e) density = 1 g cm–3 at 4°C Evaporating/
(f) boiling point = 100°C Boiling
(g) freezing point = 0°C
Solid Freezing Liquid Condensation Gas
2 4. The surface tension of water is the cohesive (ice)
force between water molecules on the (water) (Steam/ water vapour)
surface that causes it to act as an elastic
layer. This can be proven when insects like Sublimation
daddy-longlegs spiders and mosquitoes are
able to float on water. Figure 5.3  Effects of absorption and release of heat

Cohesive force Composition of Water

Figure 5.1  Surface tension 1. As we already know, water is a compound
and not a mixture.
5. Besides that, the cohesive force among the
water molecules and the adhesive force 2. The water molecule is made up of two
between the water molecules and other hydrogen atoms and one oxygen atom and
molecules like the xylem capilary cell walls can only be separated through chemical
enable water to be brought from the roots processes.
to the leaves. This phenomenon is known
as capillary action. O

Adhesive force HH

Cohesive force Figure 5.4  Composition of water

Figure 5.2  Capillary action 3. The composition of water can be determined
by carrying out an electrolysis of the water.

4. Water electrolysis is a process of
decomposition of water into hydrogen and
oxygen using electrical energy.

5. During electrolysis,
• Oxygen is discharged at the positive
electrode (anode).
• Hydrogen is discharged at the negative
electrode (cathode).

244

  Science PT3  Chapter 5  Water and Solution 

EkAscpteivriimtye5n.12.1

Aim: To determine the composition of elements in water molecule.
Materials and apparatus: Distilled water, dilute hydrochloric acid, wooden splinter, matches, electrolytic
cell, switch, measuring cylinders, dropper, connection wires and crocodile clip.

Procedure: P Q
Measuring
1. Two measuring cylinders are labelled as P and Q. Carbon cylinder
2. The apparatus is set up as shown in Figure 5.5. electrode
3. Several drops of dilute hydrochloric acid are dripped Water
+
into the distilled water.
Dilute hydrochloric acid
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4. The switch is connected after 10 minutes. Switch +–
5. The changes in both the measuring cylinders are
Figure 5.5  The apparatus of set-up
observed.

6. After 10 minutes, the switch is disconnected and the volume of the gas in both the measuring cylinders
are recorded.
Form
Form
7. The gas collected in measuring cylinder P is tested with a glowing wooden splinter, whereas the gas
collected in measuring cylinder Q is tested with a burning wooden splinter.

8. All the observations are recorded in the form of a table. 2

Observation:

Measuring Volume of gas Effect on wooden splinter
cylinder (ml)
Glowing wooden splinter light up.
P 4.0 Burning wooden splinter is extinguished and produce a ‘pop’ sound.

Q 8.0

Discussion:

1. Distilled water that is used in this activity should be mixed with some dilute acid to increase the electrical
conductivity in water. Distilled water (pure water) is a poor conductor of electricity.

2. The results of the observation on the gas test show that oxygen gas is released at the positive electrode
whereas hydrogen gas is released at the negative electrode.

3. The ratio of the volume of gas collected inside measuring cylinder P compared with the gas collected in
the measuring cylinder Q is 1 : 2.

Conclusion:
A water molecule is made up of two hydrogen atoms and one oxygen atom.

The Effect of Impuritiess on the 3. The presence of salt in water reduces the
Melting Point and Boiling Point of freezing point and increases the boiling
Water point of the water. This causes the water
that was mixed with salt to take a longer
1. Adding impurities into water can change the time to freeze and boil compared to distilled
physical characteristics of the water, such as or pure water.
the taste, smell and colour.
4. Impurities also cause the density of the
2. For example, sea water tastes salty because water to increase, for example sea water has
it contains dissolved salts. a higher density than fresh water.

245

  Science PT3  Chapter 5  Water and Solution

EkAscpteivriimtye5n.2.1

Aim: To observe the effect of impurities on the melting point of ice and the boiling point of water.
Materials and apparatus: Distilled water, ice, thick towels, common salt (table salt), beakers, conical flask,
thermometer, spatula, Bunsen burner, tripod stand, wire gauze, two-holed cork, glass tube and stopwatch.

A  The effect of table salt on the melting point of ice
Procedure:

Thermometer
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Ice + Towel Ice
salt

JKForm
Form
Figure 5.6 The set-up of apparatus

1. Two beakers of equal size are wrapped with a towel each are labelled as J and K.
2. Several ice cubes are put into both the beakers.
3. A spatula of salt is added to the ice in beaker J.

2 4. Once the temperature of ice in both the beakers becomes constant, the reading on the thermometer is
recorded.
5. The changes that occured on the ice are observed.

Observation:

Beaker Thermometer readings when the temperature of ice is constant (°C)
J –4
K 0

Discussion:
1. The melting point of the ice is determined once the temperature becomes constant.
2. The melting point of pure ice is 0°C whereas the melting point of ice with salt –4°C, which is lower than

the melting point of pure ice. This shows the presence of salt decreases the melting point of ice compared
to the melting point of pure ice.

Conclusion:
The presence of salt (impurities) reduces the melting point of ice.

B  The effect of table salt on the boiling point of water
Procedure:

Thermometer

Glass tube

Distilled Distilled water
water +
salt

Bunsen burner

L M
Figure 5.7 The set-up of apparatus

246

  Science PT3  Chapter 5  Water and Solution 

1. Two sets of apparatus are prepared as in the diagram shown and the conical flasks are labelled as L
and M.

2. The temperature of water in both the conical flasks is recorded when the temperature becomes constant.
Observation:

Conical flask Thermometer reading when the temperature of water is constant (°C)
L 100
M 104
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Discussion:
1. The boiling point of water is determined when the temperature of ice becomes constant.
2. The boiling point of pure water is 100°C while the boiling point of water mixed with salt is 104°C which

is higher than the boiling point of pure water. This shows that the presence of salt increase the boiling
point of water.

Conclusion:
The presence of salt (impurities) increases the boiling point of water.
Form
Form
the surroundings to move rapidly and then
Daily Application escape into the air. 2

Lots of csoaoltktinogwraetceipr ewshgeinvewues binosiltrsuocmtioenthsinogn.
adding PAK-21
Why?

Evaporation of Water Figure 5.8 Evaporation of water

Evaporation is a process where liquid 2. Water evaporation removes part of the
changes to gas on the surface of the water energy from the water, causing the remaining
at any temperature. water to become colder. Therefore, when we
sweat, the sweat evaporates and cools our
1. During evaporation, the water molecules on body because part of the heat is removed
the surface of the water gain energy from from our body.

Factors that Affect the Rate of Water Evaporation

Ekxsppeerirmimeennt 52.1

Aim: To study factors that affecting the rate of evaporation of water.

A Humidity
Problem statement: Does humidity influence the rate of evaporation of water?
Hypothesis: The higher the humidity, the lower the rate of evaporation of water.

247

  Science PT3  Chapter 5  Water and Solution

Manipulated variable: Humidity
Responding variable: Rate of evaporation of water
Constant variable: Surrounding temperature, surface area and water volume and the movement of air.
Materials and apparatus: Anhydrous cobalt chloride paper, thread, water, anhydrous calcium chloride,
bell jars and beakers.
Procedure:

1. Two pieces of anhydrous cobalt chloride paper are dipped
in water.

2. The apparatus is set up as in Figure 5. 9.
3. The piece of cobalt chloride paper that dries first is

observed.

Observation:
Cobalt chloride paper K dries first.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Wet cobalt chloride paper Anhydrous
Bell jar calcium
chloride

JK
Figure 5.9 The set-up of apparatus

Discussion:

Form
Form
1. Anhydrous calcium chloride in bell jar K absorbs water vapour in the air, causing bell jar K to have low
humidity.

2. The water in bell jar J produces water vapour causing the bell jar J to have high humidity.

2 3. Observation shows water evaporates faster when the humidity is low.
Conclusion:
Hypothesis is accepted. The higher the humidity, the lower the rate of evaporation of water.

B  Surrounding temperature

Problem statement: Does the surrounding temperature affect the rate of evaporation of water?

Hypothesis: The higher the surrounding temperature, the higher the rate of evaporation of water.

Manipulated variable: Surrounding temperature

Responding variable: Rate of evaporation of water

Constant variable: Humidity, surface area and water volume and the movement of air

Materials and apparatus: Anhydrous cobalt chloride paper, water, table lamp and a piece of white tile.

Procedure: Wet cobalt chloride paper
1. Two pieces of anhydrous cobalt chloride paper are
Lamp
labelled as L dan M.
2. Both the pieces of paper are dipped in water. Tile
3. Apparatus is set up as in Figure 5.10. LM
4. The piece of cobalt chloride paper that dries first is Figure 5.10 The set-up of apparatus

observed.

Observation:
Cobalt chloride paper M dries first.

Discussion:

1. The surrounding temperature below the lamp is higher because the table lamp produces heat energy.
2. Observation shows water evaporates faster when the surrounding temperature is higher.

248

  Science PT3  Chapter 5  Water and Solution 

Conclusion:
Hypothesis is accepted. The higher the surrounding temperature, the higher the rate of evaporation of water.

C  The exposed surface area of water
Problem statement: Does the exposed surface area affect the rate of evaporation of water?
Hypothesis: The larger the exposed surface area, the higher the rate of evaporation of water.
Manipulated variable: Exposed surface area
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Responding variable: Rate of evaporation of water

Constant variable: Humidity, surrounding temperature and the volume of water and the movement of air.

Materials and apparatus: Anhydrous cobalt chloride paper, water, cellophane tape and glass slides.

Procedure:

1. Two pieces of anhydrous cobalt chloride paper are dipped Wet cobalt Wet cobalt
in a container with water until the whole pieces of paper chloride paper N chloride paper O
are moist.
Form
2. Cobalt chloride paper N is stuck to a glass slide using Form
cellophane tape and cobalt chloride paper O is folded
into two and stuck on a glass slide using cellophane tape. Cellophane tape Glass slide Cellophane tape 2
Figure 5.11 The set-up of apparatus
3. Both the slides are placed under the sunlight.
4. The piece of cobalt chloride paper that dries first is

observed.

Observation:
Cobalt chloride paper N dries first.

Discussion:

1. The cobalt chloride N paper has a larger exposed surface area compared to the cobalt chloride paper O.
2. This shows that water evaporates faster when the exposed surface area of water is larger.
Conclusion:
Hypothesis is accepted. The larger the exposed surface area, the higher the rate of evaporation of water.

D  Air movement
Problem statement: Does the air movement affect the rate of evaporation of water?
Hypothesis: The faster the movement of the air, the higher the rate of evaporation of water.
Manipulated variable: Movement of air
Responding variable: Rate of evaporation of water
Constant variable: Humidity, surrounding temperature and the volume of water and the exposed surface

area.
Materials and apparatus: Anhydrous cobalt chloride paper, water, cellophane tape, glass slides and a fan.

249

  Science PT3  Chapter 5  Water and Solution

Procedure:

Fan

Wet cobalt chloride paper

PQ
Figure 5.12  The set-up of apparatus

1. Two pieces of anhydrous cobalt chloride paper are dipped into a container with water until the whole
pieces of paper are moist.

2. The apparatus is prepared as in Figure 5.12. Cobalt chloride paper P is placed far from the rotating fan
but cobalt chloride paper Q is placed below the rotating fan.

3. The piece of cobalt chloride paper that dries first is observed.
Observation:
Cobalt chloride paper Q dries first.
Discussion:

2 1. The fan transports the water vapour released from the surface of the water to another place.
2. The rapid movement of the air causes the water to evaporate faster.
Conclusion:
Hypothesis is accepted. The faster the air moves, the higher the rate of evaporation of water.
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Form

Humidity Air movement

Humidity refers to the total amount of water vapour Moving air sweeps away water from the surface
in the air. Dry air has a little water vapour. Therefore, of the water to other places. This causes water to
dry air can support the water molecules that are evaporate easily beause the air around the surface
released from the water surface. This increases the of the water is drier. The faster the movement of
evaporation rate. the air, the faster the water evaporates.

Exposed surface area Surrounding temperature

When the exposed surface area is larger, this When the surrounding temperature is high, the
enables lots of water to be released into the air and kinetic energy of the water molecules increases
increases the evaporation rate of water. causing them to move faster and are released
into the air more easily. Therefore, the rate of
evaporation of the water increases.

Figure 5.13 Factors that affect the rate of evaporation of the water

250

Wet clothes are hung out widely open to increase   Science PT3  Chapter 5  Water and Solution 
their exposed surface area to sunshine. Hence
the clothes would dry quickly. Seafood like fish, squids and prawns are dried
under the sunshine to dry so that they can be
kept longer. This is because microorganisms
cannot survive
without water.

Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Application
of Water

Evaporation in
Everyday Life

A hair dryer is used to dry wet hair. It Sea water is evaporated to obtain
blows hot air to increase powdered
the evaporation rate salt.
by increasing the
movement of air.

Form
Form

Figure 5.14 Application of water evaporation in everyday life 2

HPOraTkStisCFhoramllaetnifg1e 1 SCIENCE IINNFFOO

Suzie washes her school uniform on Processed food

Sunday. Due to cloudy weather on that Processed food is produced using the freeze drying technique.
Through this method, food is put into a deep vacuum to
day, her clothes have not dried yet, she evaporate its water. This method preserves most of the
nutrients in the food. Among the food produced through this
uses the hair dryer to dry her clothes. Is method are coffee powder and milk powder.

her action practical? PAK-21

Formative Practice 5.1 Tips

1. The sweat on our body would evaporate faster when we • Water evaporation happens only
stand under a rotating fan. Why? on the surface of the water.

2. Figure 5.15 shows the shape of water that has dropped on • Evaporation happens at any
a leaf. Relate the shape of the water with one characteristic temperature.
of water.
• Evaporation rate increases when
Figure 5.15 the:
(i) surrounding temperature
3. Determine the following types of forces: increases
(a) The force that exists among the water molecules. (ii) air movement increases
(iii) exposed surface area
() increases
(iv) the humidity is low

(b) The force that exists between the water molecule and

other molecules. ( )

251

  Science PT3  Chapter 5  Water and Solution Solutes are substances that can dissolve
in liquids.
5.2 Solutions and Rate of Solubility

Solute, Solvent and Solution A solvent is the liquid that can dissolve
1. River water, sea water and lake water are solutes.

examples of solutions that can be found 2. A solution has varying concentration
around us. depending on the ratio of solutes to solvents.

A solution is the mixture formed when 3. A solution can be classified into three types,
solute dissolves in a solvent. they are dilute solution, concentrated
solution and saturated solution.
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Dilute solution Concentrated solution Saturated solution
• Contains a little solute.
• Can dissolve more solute. • Contains lots of solute. • Contains the maximum amount
• Can dissolve a little solute. of solute.
2
Form • Cannot dissolve any more
Form solute.

Figure 5.16 Diluted solution, concentrated solution and saturated solution

Solution and Suspension A suspension is a cloudy mixture formed
from the solutes that do not dissolve in
1. Solutions and suspensions are mixtures. liquid.
The difference between them is that a
solution contains dissolved substances 2. Muddy water, fruit juice and liquid medicine
while a suspension contains undissolved are examples of suspensions.
substances.

Solution Suspension

(a) Solutes in solutions are dispersed evenly in (a) Solutes that do not dissolve in liquids
solvents. cause the mixture to turn cloudy.

(b) It is always homogenous in terms of colour and (b) Suspensions do not allow light to
appearance throughout all parts of the solution. pass through because the size of the
suspension particles are too big.
(c) Solution may be colourless or coloured. However,
the uniform colour causes the solution to look (c) A precipitate forms at the base if
clear. left for a while and the suspension
leaves remnants when filtered.
(d) Solutions are transparent because the tiny solute
particles allow light to pass through.

(e) Solutions do not leave remnants when filtered.

252

  Science PT3  Chapter 5  Water and Solution 

Solubility Table 5.1

Solubility is the maximum quantity of Factors Explanation
solute in gram unit that can dissolve in
100 ml of solvent at a specific temperature. Temperature The higher the temperature of
of solvent the solvent, the higher the rate
1. 80 g of sodium chloride dissolves in
100 cm3 water at a temperature of 20°C of solubility.
to form a saturated solution. Therefore,
the solubility of sodium chloride is 80 g per
100 cm3 at a temperature of 20°C.

2. The solubility rate is influenced by a several
factors such as the temperature of the
solvent, size of the solute and the stirring
rate.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. Size of The smaller the size of the
solute solute, the higher the rate of
solubility.

Rate of The higher the rate of stirring,
stirring the higher the rate of solubility.

Ekxsppeerirmimeennt 52.21 Form
Form
Aim: To study factors that affecting the rate of solubility.
2
A  Temperature of the solvent

Problem statement: Does the temperature of the solvent affect the rate of solubility?
Hypothesis: The higher the temperature of the solvent, the higher the rate of solubility.
Manipulated variable: Temperature of solvent

Responding variable: Rate of solubility

Constant variables: Volume of solvent, stirring rate dan size of solute

Material and apparatus: Distilled water, fine sugar, measuring cylinder, beaker, glass rod, thermometer,
tripod stand, wire gauze, Bunsen burner and spatula.

Procedure:

Glass rod Thermometer
Beaker

Glass rod Fine sugar 100 ml of
distilled water

Fine sugar 100 ml of Bunsen
distilled water burner

JK
Figure 5.19 The set-up of apparatus

1. 100 ml of water is poured into beakers labelled J and K.
2. Beaker K is heated until it reaches a temperature of 60°C.
3. Then, 2 g of sugar is added to both the beakers and the mixture is stirred at the same rate until all the

sugar dissolves completely.
4. The sugar in the beakers are observed to determine the sugar in which beaker dissolves faster.

253

  Science PT3  Chapter 5  Water and Solution

Observation:
Sugar in beaker K dissolves faster.
Discussion:
1. Sugar dissolves faster in water at higher temperature and dissolves slower in water at lower temperature.
2. The hot water particles have a higher kinetic energy. These particles move at a faster speed and collide

against the sugar particles more frequently. The sugar particles are dispersed in the water faster. Therefore,
the higher the temperature, the faster the sugar dissolves.

Conclusion:
Hypothesis is accepted. The higher the temperature of the solvent, the higher the rate of solubility.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
B  Rate of stirring

Problem statement: Does the stirring rate affect the rate of solubility?
Hypothesis: The higher the stirring rate, the higher the rate of solubility.
Manipulated variable: Stirring rate

Responding variable: Rate of solubility
Form
Form
Constant variable: Volume of solvent, temperature of solvent and size of solute

Material and apparatus: Distilled water, fine sugar, measuring cylinder, beakers, glass rod and spatula.

2 Procedure: Stir fast Stir slowly

100 ml of water
+

L 5 g fine sugar M
Figure 5.20 The set-up of apparatus

1. The apparatus is set up as in Figure 5.20.
2. The mixture in beaker L is stirred at a high speed and the mixture in beaker M is stirred slowly.
3. The sugar in which beaker dissolves earlier is determined.
Observation:
The sugar in beaker L dissolves faster.
Discussion:
1. Stirring moves the water particles quickly and causes the water particles to collide against the sugar

particles frequently. As a result, the sugar dissolves quickly.
2. The increase in stirring rate causes the water particles to move at a higher speed and collide against the

sugar particles more frequently. As a result, the sugar dissolves faster.
Conclusion:
Hypothesis is accepted. The higher the stirring rate, the higher the rate of solubility.

C  Size of solute
Problem statement: Does the size of the solute affect the rate of solubility?
Hypothesis: The smaller the size of the solute, the higher the rate of solubility.
Manipulated variable: Size of solute

254

  Science PT3  Chapter 5  Water and Solution 

Responding variable: Rate of solubility
Constant variable: Volume of solvent, temperature of solvent and stirring rate
Materials and apparatus: Distilled water, fine sugar, coarse sugar, measuring cylinder, beaker, glass rod

and spatula.
Procedure:

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.5 g fine100 ml of5 g coarse
sugar water O sugar

N

Figure 5.21 The set-up of apparatus

1. The apparatus is set up as in Figure 5.21.
2. The mixture is stirred at the same stirring rate.
3. The sugar in which beaker dissolves earlier is determined.

Observation: Form
The sugar in beaker N dissolves faster. Form

Discussion: 2
The surface area of the fine sugar colliding against the water particles is larger compared to the coarse sugar’s
surface area. Therefore, fine sugar dissolves faster than coarse sugar.

Conclusion:
Hypothesis is accepted. The smaller the size of the solute, the higher the rate of solubility.

Colloid Solid form Marshmallow
Sol
A colloid is a mixture of two or more solutes Gold sol, sulphur sol, ink and
that are dispersed evenly in a solvent. Solid sol paint

1. A colloid is a mixture which is placed Stained glass and black
between a solution and a suspension diamond
because a colloid does not produce a clear
mixture or sediments. Water as a Universal Solvent

2. Table 5.2 shows the types of colloids and 1. Water is a universal solvent because it can
examples. dissolve almost all substances be it solids,
liquids or gases.
Table 5.2
2. Solutions with water as its solvent are
Types of Examples called aqueous solution. Water is used as a
colloids domestic solvent and also as raw material in
the manufacturing, agriculture and medical
Aerosol Smoke, mist and dust in the industries.
air
3. Among the uses of water as a universal
Emulsion Milk, coconut milk, solvent are:
mayonnaise and fish oil (a) Dissolving detergents used in the
washing and cleaning processes.
Solid Jelly, pearl and opal (b) Dissolving fertilisers to enable them to
emulsion be easily absorbed by roots of plants.

Foam Soapsuds and cream

255

  Science PT3  Chapter 5  Water and Solution Formative Practice 5.2

(c) Dissolving chemical substances in the 1. Based on the statement below, identify the
laboratory. solute, solvent and the solution.

(d) Liquid medicine uses water in its Antiseptic is a mixture of iodine crytals
preparation. and alcohol.

4. The benefits of water as a solvent compared 2. Figure 5.22 shows three types of mixtures P,
to other solvents are water is easily available, Q dan R.
cheaper and safe to manage.
PQ R
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.Organic Solvents

1. Some substances that cannot dissolve in
water will dissolve in organic solvents.

2. An organic solvent or a non-aqueous solvent Figure 5.22
is an organic compound containing carbon
elements that can be used to dissolve (a) Determine whether P, Q and R are a
solutes. solution, suspension or a colloid.

3. Examples of common organic solvents used (b) Give one example of a substance similar
in daily life are alcohol, chloroform, petrol, to P, Q and R.
benzene and turpentine.
Form (c) Which mixture would have sediments at
Form Table 5.3 its base?

2 Organic Uses 3. Suggest a suitable organic solvent to remove
solvents the following stains:
(a) Lipstick mark
Alcohol • As an antiseptic (b) Coffee / tea stains
• To produce perfume
• To produce polishing liquid
• To remove ink stain and

chlorophyll

Kerosene • To produce fuel for oil lamp Daily Application
• To remove dirt or paint, oil
to remove
or grease stains PAK-21

Acetone, • To produce nail varnish and Wruhstatstsauinbsstaonnctehecasnchboeoul suendifoartmhso?me
amyl lacquer
acetate
• To produce cosmestic items
such as lipsticks

Turpentine • To dilute paint and remove
paint traces

• To dilute varnish

Ether • To extract oil 5.3 Water Purification and Water
Supply

Chloroform • To stick plastic 1. Water is the Earth’s most valuable natural
resource. All living things depend on
Benzene • As a solvent in the water.
chemistry laboratory
2. Water covers 75% of the Earth’s surface but a
• Dissolves rubber and large part of it cannot be consumed directly
removes oil stains and by human beings.
grease

256

3. This is because there are impurities and   Science PT3  Chapter 5  Water and Solution 
microorganisms in the water source.
5. Water purification removes impurities,
4. Water has to be cleaned and treated before microorganisms, odour, taste and colour.
it is used for drinking to avoid diseases.
6. Among the water purification methods
are filtration, boiling, chlorination and
distillation.

Chlorination Filtration

Chlorine

River water

(a) Chlorine is used in liquid form and it is a
poisonous substance.

(b) Kills microorganisms in water.
(c) Does not eliminate dissolved substances and

suspended particles.
(d) Excessive use gives an unpleasant smell and

is harmful to health.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. River water

Filtrate

(a) Eliminates big-size suspended particles.
(b) Does not eliminate fine suspended particles,

dissolved substances and does not kill
microorganisms in water.
(c) Not safe to drink because it still contains
microorganisms.
Form
Form

2

Boiling Distillation

River water Thermometer Liebig condenser
Distillate
River water

(a) The boiling point of water is 100°C at normal (a) Produces distilled water.
atmosphere pressure. (b) Eliminates suspended impurities, dissolved

(b) Kills microorganisms in water. substances and microorganisms.
(c) Does not eliminate dissolved substances and (c) Not suitable for drinking because the water

suspended particles. does not contain any mineral salts needed by
the body.

Figure 5.23 Water purification method

Water Supply System 3. Water from these sources are collected in
catchment areas and channelled to water
1. Raw water is the most used water resource purification plants to be treated before it is
by humans to meet their needs in life like channelled to the consumers.
bathing, drinking, washing dishes and
others. 4. Substances like algae, bacteria and minerals
are eliminated in the water purification
2. Our country’s raw water supply source process.
originates from river water, streams and
rain water.

257

  Science PT3  Chapter 5  Water and Solution

Table 5.4

Process Function
Filtration Eliminates large suspended particles like leaves, tree branches and others.
Oxidation Increases the oxygen content in water to eliminate unpleasant smell and taste.
Coagulation Alum is added to coagulate the suspended particles, whereas slaked lime is added
to reduce water acidity.
Sedimentation Suspended particles that are coagulated deposit at the bottom of the tank.
Filtration Eliminates remnants of suspended substances using sand filters.
Chlorination Kills microorganisms in water.
Fluoridation Prevents tooth decay.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
Oxidation tank
Alum and slaked lime

Filtration tank

Sendimentation tank

Coagulation tank

Form Pump station Mixing tank
Form Removes
Water reservoir

2

Filtration tank

Clear water tank

To user Flouride Chlorine NEWater
compound INFO
Pump station

Figure 5.27  Water supply system

Water Sustainability

Water pollution

1. The demand for clean water continues to increase with the increasing population. Unfortunately,
natural water continues to decrease due to water pollution activities.

2. The discharge of domestic waste, development projects, agriculture and industrialisation are the
factors of water pollution.

TIMSS Challenge 1 Formative Practice 5.3

State why oil spills in the rivers and 1. State the appropriate water purification method and their
seas have a negative effect on the application:
environment. (a) in the swimming pool
(b) in sterilising medical instruments
258 (c) in preparing chemical solutions
(d) in preparing drinking water

2. Name two of the latest water purification methods.

3. Suggest two main steps in controlling water pollution through
prevention.

PT3 Practice   Science PT3  Chapter 5  Water and Solution 

5

SECTION A

1. Figure 1 shows the electrolysis of water. The gas 3. Which of the following are the correct examples
collected are labelled as gas X and gas Y. for types of colloids?

Penerbitan Pelangi Sdn Bhd. All Rights Reserved.XY Emulsion Foam Aerosol Sol
Measuring Cream
Carbon cylinder A Smoke Paint Milk Paint
electrode
Water + dilute Milk
hydrochloric B Milk Cream Smoke Smoke
acid
C Paint Smoke Cream

Switch +– D Cream Milk Paint

Figure 1 4. Figure 3 shows the form of water that is known
as dew.
What is gas X and gas Y? Form
Form
Gas X Gas Y
A Oxygen Hydrogen 2
B Hydrogen Oxygen
C Oxygen Nitrogen
D Nitrogen Oxygen

2. Figure 2 shows the solubility of substances W, X, Figure 3
Y and Z in water with different temperatures.

Solubility in 100 ml water W Which of the following statements are true about
80
dew?

70 X I The shape of dew is caused by the adhesion
60
50 Y an cohesion of water.
40 Z
II Dew is formed due to condensation of water

vapour in the air.

30 III Adhesion between water molecules cause the

20 dew to be round in shape.

10 IV The attractive forces between water molecules

0 Water are called adhesive forces.
0 10 20 30 40 50 60 temperature (°C)
A I and II C II and III

Figure 2 B III and IV D I and IV

Based on the graph shown in Figure 2, what can 5. Which of the following statements are true about
be concluded about the solubility of substances fruit juice and sugar solution?

in water? I Fruit juice is a suspension.
II Fruit juice and sugar solution are transparent.
A The solubility of all substances in water is the III Sugar solution produces a precipitation at the
same.
bottom of the container.
B The solubility of substance W is influenced by
water temperature. IV Sugar solution is homogenous in its colour
and appearance.
C The solubility of substance Y is not dependent
on water temperature. A I and II
B III and IV
D The solubility of substances are influenced by C II and III
types of material and water temperature. D I and IV

259

  Science PT3  Chapter 5  Water and Solution Definition

SECTION B

1. (a) Match the following terms to its meaning.
Term

(i) Solution • • Substance that dissolves in liquid.

• • Homogeneous mixture of two or more substances.
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.(ii) Solute

[2 marks]

(b) Name the non-water solvent that is suitable to solve the following problems:

Problem / Issue Non-water solvent
(i) To prepare shellac solvents [2 marks]
(ii) To remove paint stains on marble floors

Form
Form
SECTION C

2 1. Figure 1.1 shows the situation in a flooded area.

Figure 1.1 [2 markah]
(a) Is the flood water pure water? [1 markah]
(b) Why did the two cars in Figure 1.1 sink but the boat float?

(c) Nani had to hang her wet clothes inside the house because the area outside her house was flooded.
[2 markah]
Explain why the wet clothes took longer time to dry.

(d) A flood volunteer filled two kettles, P and Q which were equal in size with the same volume of water. He
added coffee powder and sugar into kettle Q. Water in both kettles were heated until boiling.

P Q
(Water) (Water + coffee powder + sugar)
Figure 1.2

In your opinion, which water in the kettle took longer time to boil? [3 markah]
Explain your answer.

260

Form 1 of a ream of paper is divided by 450. In SECTION B Form
this way, the mass of 1 sheet of paper Form
1Chapter Introduction to Scientific is estimated. 1. (a) (i) Beaker
Investigation (ii) Filter funnel
Daily Application (b) (i) Measures the time
(ii) Measures the length 1
Air conditioner is best placed at the top
Formative Practice 1.1 of the wall of a room because it produces SECTION C
cold air. The cold air which is more dense
1. A natural phenomenon is an observable than warm air will go down in the room and
event which is not man-made. replace the warm air. At the same time, the
less dense warm air goes up and the room
2. • Invention of telephone allows people is cooled very quickly.
to communicate at a distance.

• Invention of Internet allows people to
search and access a vast amount of
information from home.

3. Doctor / Botanist / Nurse / Zoologist
(Accept other reasonable answers)
Penerbitan Pelangi Sdn Bhd. All Rights Reserved. 1. (a) (i) Measuring cylinder

(ii) To determine the volume of liquids

(iii) 22.0 cm3

(iv) Burette, pipette

(v) Water displacement method
Mass
(b) (i) Density = Volume

HPOraTkStisCFhoramllaetnifg1e 1 (ii) The density of gold = 20
1

= 20 g cm-3

The densitiy of pure water is 1 g cm-3 and the The density of glass = 2
volume of water given is 73.6 cm3. 1
Formative Practice 1.2 Mass of water
= Density of water x Volume of water = 2 g cm-3
1. The bottle contains chemical that = 1 x 73.6
catches fire easily / flammable. = 73.6 g (ii) Gold is more dense than glass

2. A fire may occur. (iv) The mass of gold is higher than
3. Get out as quickly and safely as
that of glass.
possible from the fire to a safer place
and report to the teacher. When water turns into ice, its mass remains 2Chapter Cell as the Basic Unit of
unchanged. Therefore, 73.6 cm3 of water will Life
Formative Practice 1.3 freeze to form 73.6 g of ice.

Mass of water = Mass of ice = 73.6 g.

As given, the density of ice = 0.92 g cm-3. TIMSS Challenge 1
Hence, the volume of ice can be calculated:
Methylene blue solution is used to colour
1. S.I. unit Symbol of Volume of ice = __M_a_s_s__o_f _ic_e__ (dye) the cheek cell so that the structure can
S.I unit Density of ice be seen clearly under a microscope.
Physical
quantity kg 73.6 g TIMSS Challenge 2
= 0.92 g cm-3
Mass kilogram s

Time second K = 80 cm3

Temperature Kelvin Formative Practice 1.5 Chloroplast and cell wall

2. (a) 1 200 m 1. Density of water HPOraTkStisCFhoramllaetnifg1e 1
(b) 10.08 m
(c) 0.57 m = _1__0_0_0_k_g_ x ___1__0_0_0_g___ Blood is not a cell but a tissue because it
1 m3 1 000 000 cm3 contains different cells (red blood cells, white
blood cells, plasma and platelets) that work
Formative Practice 1.4 = 1 g cm-3 together to achieve a specific function in our
body.
1. Measuring tape Hence, 1 cm3 of water has a mass of 1 g.

2. A clinical thermometer is more accurate 2. (a) Egg is denser than water. Formative Practice 2.1
than a laboratory thermometer because (b) The egg will float on the water.
clinical thermometer can measure (c) Ice floats on the ocean water.
temperature accurately up to 0.1°C,
whereas laboratory thermometer can Formative Practice 1.6 1. 5 → 1 → 3 → 4 → 2
measure with the accuracy of only 1°C.
Make a new hypothesis and carry out an 2. Nerve cells – Receive and send nerve
3. (a) Vernier calipers experiment to test the hypthothesis. impulse
(b) 2.53 cm
(c) To obtain a more accurate reading, Formative Practice 1.7 Sperm cells – Involved in reproduction
zero error has to be taken into
consideration. No. Aishah should be honest while recording Muscle cells – Allow body movement
and validating data.
(d) • If the zero error is a positive zero Red blood cells – Transport oxygen
error, the actual reading should
be 2.53 – 0.04 = 2.49 cm. 3. The differences between an animal cell
and plant cell are as below.

• If the zero error is a negative Animal cell Plant cell
zero error, the actual reading No cell wall Has cell wall
should be = 2.53 – (-0.04) PT3 Practice
1
No chloroplast Has chloroplast
= 2.57 cm SECTION A No fixed shape Has fixed shape

4. Weigh the mass of a ream of A4 paper 1. B 2. A 3. C
(450 sheets of paper). Then, the mass 4. D 5. C

531

  Science PT3  Answers

4. Unicellular organisms are organisms HPOraTkStisCFhoramllaetnifg1e 2 HPOraTkStisCFhoramllaetnifg1e 3
that consist of only one cell while

multicellular organisms are organisms

that consist of more than one cell. Reptiles and amphibians are found less Yellowish and concentrated urine is a sign of

Form in the Arctic because of the extreme cold dehydration. Be sure to drink enough water to
Form
HPOraTkStisCFhoramllaetnifg1e 2 temperatures in the Arctic. Reptiles and maintain very light-coloured urine.
amphibians are unable to maintain their body

1 The number of white blood cells produced will temperature. The body temperature of reptiles PT3 Practice
increase to fight or destroy the pathogen that SECTION A
enters our body. and amphibians will change according to the 3
external environment. When the temperature
is too low, their body temperature will also

decrease. This will affect their body function 1. A 2. C 3. D
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.Formative Practice 2.2and can lead to death. Therefore, reptiles and
amphibians are difficult to survive in the Arctic. SECTION B

1. The food (glucose) made by the plants Daily Application 1. (a) (i) Stoma
is kept in the form of starch. Therefore, (ii) Guard cells
one of the ways to test if photosynthesis Emergency treatments that can be done if a (b) (i) guard cells
has occurred is to test for the presence friend is attacked by a heatstroke: (ii) increase
of starch. • Fan the friend while wetting his or her
SECTION C
2. (a) X: Photosynthesis skin with water.
Y: Cell respiration • Apply ice packs on the friend’s armpits, 1. (a) (i) Homeostasis
(b) X: To make food / glucose (ii) While jogging, more oxygen
groin, neck, and back.
Y: To produce energy • Provide cool drinks or isotonic drinks to is needed for cell respiration.
(c) Process Y Therefore, the heart need to
the friend. pump more blood to cells in
PT3 Practice 2 • Loosen the friend's clothing. the body. Thus, the rate of
Heatstroke prevention: heartbeat will increase.
SECTION A • Drink more water. (b) Cause: The plant lost a lot of
1. C 2. A 3. A • Wear lightweight, light-coloured, loose- water.
Adaptation: The stoma pores on
SECTION B fitting clothing, and a wide-brimmed hat if the leaves are closed to reduce
must do outdoor activities on a hot day. additional water loss from the leaf
1. (a) (i) Plant cell to the environment.
(ii) Animal cell Formative Practice 3.1 (c) (i) Kidney
(b) (i) used (ii) Less than 58 ml/h. The body
(ii) absorbed 1. We do not sweat a lot on a rainy day. loses a lot of water through
Therefore, the excess water in the body sweat.
will be removed from the body through
SECTION C urine. 4Chapter Reproduction

1. (a) Carbon dioxide + Water → Glucose 2. When our body temperature drops, the HPOraTkStisCFhoramllaetnifg1e 1
+ Oxygen heat production will increase and heat
loss will decrease through these actions: Tiger: Internal fertilisation
(b) Cell respiration process Toad: External fertilisation
(c) • Can keep the balance • Blood vessels constrict. External fertilisation is less efficient because:
• Sweat less. • A large number of gametes are
of oxygen content in the • Hairs stand erect.
atmosphere. • Skeletal muscles will contract and released into the water and wasted.
• To support organism's life. • Gametes live for only a short time, and
(d) Photosynthesis process cannot be relax actively.
carried out without plants. When • Hormones will be secreted to many are lost in the water.
plants are depleted, the process • Offspring are often eaten by predators
of photosynthesis also decreases, increase the body metabolism.
resulting in lack of oxygen supply and reduces the chances of surviving
3. Dogs cannot remove much heat into adulthood.
3Chapter through sweating, so they always stick
Coordination and Response out their tongue which allows saliva to
evaporate from the tongue to reduce
the body temperature.

4. • Transpiration is the process of
losing water from the surface of
plant leaves in the form of water

vapour to the atmosphere through Formative Practice 4.1
stomata.

HPOraTkStisCFhoramllaetnifg1e 1 • Transpiration helps plants to absorb 1. (a) Sexual reproduction is the
and transport water and minerals production of offspring through the

from the soil to all parts of the fusion of a male gamete and a

Skin is the organ that plays an important role plants to replace the water lost to female gamete, whereas asexual

in regulating body temperature. Skin injuries the surrounding through the leaves. reproduction is the production

will affect the function of skin to sweat Transpiration also helps in cooling of offspring from a single parent

when the surrounding is hot. This will affect down the plants when water gets without involving any gametes.

the homeostasis of Sally's body because evaporated on a hot day. This (b) Internal fertilisation occurs inside

she cannot regulate her body temperature means transpiration helps plants the body of the female parent

well. Therefore, Sally can only stay in an to regulate water content and after the male parent deposits his
environment where the temperature can be maintain the water content to be in sperms into the female’s body,
maintained at a constant temperature. a balanced and stable condition. whereas external fertilisation
occurs outside the body of the

532

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