LOWER SECONDARY SCIENCE TEXTBOOK

Geothermal energy
The source of geothermal energy is the Earth’s core.
The core and mantle of the Earth are very hot. In some
places, hot rocks found deep underground heat up the
underground water, turning it into steam. The resulting jet
of steam is channelled to a turbine that can be used to
generate electricity.

Electrical substation

Electricity Water storage
generator Pump

Turbine
driven by

steam

Steam

Hot dry Water pumped into
rock bed the ground

How geothermal energy is generated

Fuel cells
A fuel cell is a device that converts the chemical energy in
fuel into electricity. An example of a fuel cell is the hydrogen
fuel cell. It makes use of hydrogen and oxygen to produce
electricity. Hydrogen fuel cells are used in space vehicles as
well as in some cars.

Liquid 2e+ Oxygen
hydrogen Electrolyte (from air)
(from fuel)
2H+

Heat +
water
Hydrogen could be the main fuel to take over from oil and gas.

Energy 149

Biomass
Biomass is organic matter that can be used to make
fuel to produce heat or electricity. It can be obtained
from plant and animal waste. Biomass resources can be
restocked through cultivation of crops such as fast growing
trees and grass.

Biogas (methane)

Cow shed Excrement
of livestock

Food Organic waste Gas engine
processing is decomposed Electricity
company by bacteria that
releases biogas. Heat
Raw garbage

School

Science Bites Solar energy
Solar energy comes from the Sun. Solar water heaters
Some calculators placed on the roof of a house, trap the Sun’s heat to produce
have solar cells in hot water for household use. It may also be converted
them. These are into electrical energy, which can be used for household
known as solar- appliances. Solar cells that are placed on a roof absorb
powered calculators sunlight during the day and convert it to electricity. It can
because they run generate enough energy to power a whole house.
on solar energy.
They can be used at Solar panel
night because the
solar cells store all Water
of the energy that tank
was absorbed by the
solar panels. Pipes with
cold water
Solar Pipes with hot water
cell One disadvantage is that solar cells are expensive.

150 Energy

Wind energy
Wind turbines use kinetic energy of wind (wind energy)
to generate electrical energy. Wind turbines are set up in a
large open area of land, or sea, called a wind farm.

1 Wind causes the 2 The shaft turns the
blades to rotate. generator to produce
electrical energy.

Shaft Generator

Gear

How a wind turbine works A wind farm

The disadvantage of a wind turbine is that it can only Science Bites
function in the presence of strong winds. Furthermore, it
needs open, windy areas to operate. Nuclear power
Nuclear energy stations produce
In nuclear power plants, radioactive metals such as uranium dangerous waste
and plutonium break down into lighter atoms, releasing and radiation. This
large amounts of heat energy. This energy source is called radiation can cause
nuclear energy. The heat boils water to generate steam cancer. On 15 March
which turns the turbines in the nuclear plant and produces 2011, a powerful
electrical energy. earthquake hit
Japan. The impact
damaged a nuclear
plant in Fukushima,
Japan, forcing people
living in a 20 km
radius from the plant
to evacuate. Some of
the workers suffered
radiation burns.

The Kashiwazaki-Kariwa nuclear plant in Japan is the largest WB Link Activity 7.4
nuclear-generating power station in the world. Energy 151

Tidal energy
Tidal power stations convert potential energy of the tide to
electrical energy.

The Rance Tidal Power station is the world’s first
tidal power station.

The following summarises how tidal energy is obtained.
A long wall is built across the mouth of a bay. At high tide,
the sea water fl ows through the wall to get into the bay.
The sea water fl ows through turbines placed along the wall,
causing the generators to turn and produce electricity.

Sea

Electric
generators

Water Bay
turbine
How tidal energy is obtained

At low tide, the water in the bay fl ows out to sea through
the same turbines and again, they will turn the generators
and produce electricity.

This continous movement of the tides allows the generation
of electricity as the turbines are driven by the power of the
sea in both directions.

152 Energy

Conserving energy Science Bites
Non-renewable sources of energy are limited and will run
out one day. Fossil fuels like crude oil, coal and natural ‘World Sustainable
gas are non-renewable sources that we depend on very Energy Days’ is an
much today. To prevent them from running out, we should annual conference
conserve them. held in Austria
When we use these fossil fuels, we have to use them in early March to
sparingly, wisely and effi ciently. Power stations turn the raise awareness on
energy stored in fossil fuels to electricity. By ensuring that green energy and
we do not waste electricity, we can conserve this energy. sustainability.
Here are some ways you can help conserve energy.
1. Switch off all electrical appliances when not in use.

We will be away for No! We should
30 minutes. Is it switch it off when
wise to leave the fan we are not using it.
on for that long?

Leaving appliances in energy-saving mode or ?
on stand by still consumes electricity.
Can you think of
2. Use energy saving bulbs instead of normal fi lament bulbs. some simple ways
to conserve energy
This bulb lasted in school?
just one month!
Try this
Use this energy-saving
bulb. It lasts longer! GTo troy a sthhopisping

We can choose to use applicances that require less electricity. centre and examine
the labels of different
electrical appliances.
You may also look at
different models of
the same appliance,
like a refrigerator.
Which model uses
the most electricity?
How do you know?

Energy 153

Science Bites 3. Put the lid on the saucepan while cooking.

Earth Hour falls on You should put the lid on.
the last Saturday The food will cook faster,
of March each year. so you‛ll use less gas.
It is a global event,
where households
and businesses are
encouraged to turn
off their non-essential
lights and other
electrical appliances
for one hour.

This reduces the usage of gas during cooking.

4. Walk or cycle instead of travelling by car.

Cycling is better Yes! It reduces fuel
than driving. usage and is a good
way to exercise!

WB Link Activity 7.5

This reduces petrol consumption.

Quick Check

1. What are the sources of energy in Brunei Darussalam?
2. What is the difference between renewable

and non-renewable sources of energy?
3. Give two examples of non-renewable sources of energy.
4. Give two examples of renewable sources of energy.
5. Why should we conserve energy?
6. List three ways to conserve energy.

154 Energy

Summary

Energy

Forms Conservation Sources Ways of
conserving

Non- Renewable Switching
renewable sources off unused
appliances
sources Using
energy-
Kinetic Energy Coal Hydroelectrical saving
energy can be Oil power station appliances
Electrical converted Natural Walking,
energy from one gas Geothermal cycling
form to Nuclear Fuel cells or taking
Heat another. Biomass public
energy Energy Solar transport
Light cannot be
energy destroyed.
Sound
energy Wind
Potential
energy Tidal

Gravitational Chemical Elastic
potential potential potential
energy energy energy

Energy 155

Review Questions

1 Defi ne energy.
A Energy is the ability to do work.
B Energy is the speed of doing work.
C Energy is the distance moved by an object.
D Energy is the amount of electricity produced every second.

2 What does an object need to have kinetic energy?
A Size
B Height
C Motion
D Temperature

3 The illustration below shows Azman releasing a catapult. Which of
the following states the energy conversion that occurs when Azman
releases the catapult?

A Elastic potential energy Kinetic energy
B Electrical energy Kinetic energy + Heat energy
C Elastic potential energy Kinetic energy Light energy
D Gravitational potential energy Elastic potential energy +

Kinetic energy

156 Energy

4 Examine the following statements regarding the conservation of
energy. Which statement is true?

A Energy can be created.
B Energy can be destroyed.
C Energy cannot be created or destroyed.
D Energy cannot be changed from one form to another.

5 Which of the following is a non-renewable source of energy?
A Biomass
B Sunlight
C Crude oil
D Flowing water

6 Which of the following is the best reason to conserve fossil fuels?
A They are cheap to obtain.
B They can be used repeatedly.
C They are non-renewable energy sources.
D They come in different states such as solids and liquids.

7 Classify the following energy sources as renewable or non-renewable
sources.

Sun Wind Wood Ocean waves
Coal Diesel fuel Natural gas Hydrogen fuel

8 The picture shows a hydroelectrical power station. State all the energy
conversions involved in a hydroelectrical power station.

Reservoir Dam
Water
moving Generator
downwards

Turbine

Energy 157

9 Identify four forms of energy that you can fi nd in your classroom.
10 Look at the scene below. List the ways energy is being wasted.

Write down what you would do to conserve energy.

158 Energy

Chapter Magnetism

8 In some countries, there are trains that have no wheels. They
are called Maglev trains. These trains do not touch the tracks but
are able to travel at high speeds. Powerful magnets are placed
under the trains. More magnets are placed on the tracks and
along the walls. The magnets on the tracks repel those on the
train and lift it up. Those on the walls attract the train and pull it
forward. This chapter will tell you more about magnets.

Firman Allah Subhanahu Wa Ta’ala
Tafsirnya:
… Kami juga telah menciptakan besi
dengan keadaannya mengandungi
kekuatan yang hebat dan pelbagai
faedah lagi bagi manusia (Dijadikan
besi dengan keadaan yang demikian,
supaya manusia menggunakan faedah-
faedah itu dalam kehidupan mereka
sehari-hari) dan supaya ternyata
pengetahuan Allah tentang orang yang
(menggunakan kekuatannya itu untuk)
menegak dan mempertahankan agama
Allah serta menolong rasul-rasulNya
padahal balasan baiknya tidak kelihatan
(kepadanya). Sesungguhnya Allah Maha
Kuat lagi Maha Perkasa. (25)

… And We brought forth iron wherein
is mighty power (in matters of war), as
well as many benefits for mankind, that
Allah may test who it is that will help
Him (His religion) and His Messengers
in the unseen. Verily, Allah is All-Strong,
All-Mighty (25)

(Surah Al-Hadid: 25)

Let’s Explore

• What are magnets?
• What are the characteristics of

magnets?
• What are some uses of magnets?
• How are magnetic fields formed?

Magnetism 159

8.1 Magnets and Non-
magnetic Materials

You should be able to:
• state that a magnet has two poles;
• observe that a freely suspended magnet comes to rest in a

North–South direction;
• infer that like poles repel and unlike poles attract;
• state that iron, steel, nickel and cobalt are magnetic

materials;
• distinguish between magnetic and non-magnetic materials;
• list some of the uses of magnets in everyday applications.

Magnets were used in China many years ago. Chinese
sailors used pieces of rocks as compasses to indicate the
direction in which they were travelling. These rocks, known
as lodestone, were crafted into the shape of a spoon.

Compass used by Chinese sailors

Different kinds of magnets

A magnet is a piece of metal that can attract certain metallic
materials. It aligns itself in a North–South direction when
suspended. Magnets can be of different shapes and sizes.

Horseshoe

Bar

Ring

Different kinds of magnets

160 Magnetism

Investigating magnets

If some iron filings are placed near a magnet, they will be
attracted to it. Most of the iron filings will be attracted to
the ends of the magnet. The ends of magnets have the
strongest force of attraction.

Magnet with iron filings attracted to one end

If a magnet is suspended, the end of the magnet that faces
North is called the North-seeking pole, or the North pole
(N-pole). The other end is called the South-seeking pole,
or the South pole (S-pole).
When the North poles of two magnets are brought together,
the magnets repel each other. Similarly, when the South
poles of two magnets are brought together, the magnets
repel each other.

S NN S

N SS N

Like poles of magnets repel each other.

This shows that like poles of magnets repel.

Magnetism 161

When the South pole of one magnet is placed near the North
pole of another, they attract each other.

? N SN S

Marliza dropped a Unlike poles attract each other.
magnet and it broke
into two pieces. Would This shows that unlike poles of magnets attract.
each of the two pieces Like poles repel. Unlike poles attract.
still have two poles? When a bar magnet is freely suspended, it will come to rest
with one end pointing to the North pole and the other end
WB Link Activity 8.1 pointing to the South.

N
S

NE

WS

WB Link Activity 8.2 A freely suspended magnet comes to rest
in a North–South direction.

162 Magnetism

Magnetic and non-magnetic materials

A magnet is able to attract objects that are made of iron,
steel, nickel and cobalt. These are known as magnetic
materials.

Some nails are attracted to a magnet
because they contain iron.

Certain coins are attracted to magnets
because they contain nickel.

Magnetism 163

Materials that are not attracted by magnets are known
as non-magnetic materials. Some examples of non-
magnetic materials are rubber, plastic, wood, copper and
aluminium.

These objects are made of non-magnetic materials.

Objects such as pipes and bells that are made of
copper are not attracted by magnets.

Foil and cans that are made of aluminium are not
attracted by magnets.

164 Magnetism

To distinguish between a magnet and a magnetic Try this
material
Below are two identical bars, AB and XY. One is a magnet A magnet can be
and the other is not. When a magnetic material is placed made simply by
near a magnet, both its ends are attracted to it. using a bar magnet
to stroke a magnetic
B material several
A times in the same
direction. The more
times the material is
stroked, the stronger
the magnetism it has.

A N
B S
Bar AB is made of a magnetic material.
Science Bites
However, when a magnet is placed near another magnet,
one of its ends will be attracted to the magnet. The other A magnet can lose
end will be repelled. its magnetism when
it is:
Y • dropped or
X
hammered,
X • heated, or
Y • stroked with

Bar XY is a magnet. another magnet.
Thus, magnets must
Therefore from the observations above, bar AB is a be stored properly
magnetic material and bar XY is a magnet. and away from other
magnets.

WB Link Activity 8.3

Magnetism 165

Magnets and their uses

Magnets can be used for many purposes. One of the most
important uses of magnets is in dynamos and motors. Every
power station relies on magnets to help generate electricity.
Most electrical appliances such as fans, toy cars and food
blenders have magnets in them. These appliances have a
motor with magnets to help convert electrical energy to
kinetic energy or other forms of energy.

Motors have magnets in them. A doorstopper consists of a powerful
magnet and a piece of iron or steel
that is used to hold a door open.

Magnets are used in compasses to The magnetic resonance imaging
show direction. The needle in the (MRI) scanner is a device in
compass is a magnet and rests in the hospitals that uses a large, powerful
North–South direction. magnet to produce an image of the
internal body structure.

166 Magnetism

Cards, such as Automated Teller Machine Junkyards use very strong magnets
(ATM) cards, have a magnetic strip that to separate heavy iron and steel
stores data. objects from other materials. The iron
and steel objects can then be re-used
to make new objects.

A thin, long magnet is hidden in the rubber Magnets are also used to hold objects
tube along refrigerator doors. As the in place.
refrigerator is made of steel, the magnet
keeps the door closed.

Quick Check

1. Which part of a magnet has the strongest force of attraction?
2. What happens when the North pole of one magnet is placed

near the South pole of another magnet?
3. Give two examples of magnetic materials.
4. Give two examples of non-magnetic materials.
5. List some ways in which magnets are used in our daily lives.

Magnetism 167

8.2 Magnetic Field

You should be able to:
• infer that there is a magnetic field around a magnet;
• observe and draw the patterns iron filings make:

(i) around a magnet,
(ii) between the like poles of two magnets arranged end to

end, and
(iii) between the unlike poles of two magnets arranged end

to end.

Magnetic fields

A magnetic field is the region of space around a magnet
which attracts magnetic materials.
When iron filings are sprinkled around a magnet, the
pattern they form shows the lines of force present in the
magnetic field.

Iron filings showing the lines of force around a bar magnet

When the lines of force are close together, it shows that the
magnetic field is strong. When the lines of force are further
apart, the magnetic field is weak.

NS

Lines of force around a bar magnet

168 Magnetism

If two magnets are close together, different magnetic fields
are formed.
When iron filings are sprinkled near the like poles of two
magnets placed end to end, the iron filings form a pattern as
shown in the following figures.

NN

Iron filings showing the lines of A diagram representing the lines of force
force between like poles around like poles

When iron filings are sprinkled near unlike poles placed
end to end, the iron filings form a pattern as shown in the
following figures.

SN

Iron filings showing the lines of A diagram representing the lines of
force between unlike poles force around unlike poles

Quick Check WB Link Activity 8.4

Draw the magnetic lines of force around:
i. a bar magnet,
ii. two bar magnets with like poles placed end to end, and
iii. two bar magnets with unlike poles placed end to end.

Magnetism 169

Summary

Magnets

have two come to attract repel attract are used
poles rest in
Compasses
In the North–
South direction Doorstoppers
when suspended
freely ATM cards

When the unlike Electrical
poles are facing appliances
each other

North pole When the like Separating
South pole poles are facing magnetic
each other materials
from non-
magnetic magnetic
materials materials

Steel Iron Cobalt Nickel

170 Magnetism

Review Questions

1 What are the poles of a magnet known as?
A North pole only
B South pole only
C East pole and West pole
D North pole and South pole

2 Why can a magnet be used to separate a mixture of iron nails
and sulfur?
A It is because the sulfur is repelled by the magnet.
B It is because the sulfur is attracted by the magnet.
C It is because the iron nails are repelled by the magnet.
D It is because the iron nails are attracted by the magnet.

3 Which of the following pairs are both magnetic materials?
A Iron and steel
B Steel and silver
C Iron and copper
D Copper and silver

4 The two needles are aligned as shown because the needles have
become temporary magnets. What are the poles of the ends P, Q, X
and Y?

NS

PX

QY

PQXY
A North pole South pole South pole North pole
B North pole South pole North pole South pole
C South pole North pole North pole South pole
D South pole North pole South pole North pole

Magnetism 171

5 Which object has a magnet in it?
A Stapler
B Light bulb
C Frying pan
D Loudspeaker

6 Which of the following lists metals that are attracted by magnets?
A Iron, copper, tin, cobalt
B Nickel, iron, cobalt, steel
C Copper, steel, nickel, cobalt
D Copper, iron, aluminium, nickel

7 One of these similar bars, X and Y, is a magnet. The diagrams below
show what happens when a magnet is placed near bars X and Y.
Which one of the bars is the magnet?

S N attracts X

N S attracts X

S N attracts Y

N S repels Y

8 A bar of iron is clamped close to some nails as shown below. As shown
in Diagram A, the nails are not attracted to the iron bar. A magnet is
brought close to the iron bar as shown in Diagram B. The nails are now
attracted to the iron bar. What has happened to the iron bar to allow it
to attract the nails?

Iron N
Diagram A S

172 Magnetism Iron

Diagram B

Index E
energy 115, 122
A evaporation 74, 75, 76
algae 41 electric cell 144
amphibian 43
annelid 43, 44 F
apparatus 6, 7, 8, 9, 29 fern 41
arachnid 44 filtration 79, 80
area 5, 10, 16, 17, 21, 29, 76, 109, 124, filtrate 80
125, 126, 127, 128, 151 fish 43
arthropod 43, 44 force 57, 109–114, 116–126,
effects of- 118
B freezing 74, 76, 77
bacteria 40, 45 friction 110, 113, 114, 115, 117
balance fuel 59
-triple beam 11 fossil- 59
-spring 11, 121 fungi 45
battery 63, 143, 144
biogas 160 G
biomass 147, 150, 157 geothermal energy 147, 149
birds 43 gravity 110, 111, 112, 123
boiling 16, 17, 19, 32, 57, 65, 74, 75, 82 gram 11, 13, 22
-point 57, 64, 74, 75, 77 kilo- 11, 22, 121
Bunsen burner 2, 7, 8, 9
H
C heat 7, 52, 57, 58, 114, 115
callipers 15 -ing 65
cell 93, 94, 96, 97, 98, 99, 100 hour 12
membrane 96, 97 -glass 12
wall 97, 98 humidity 28, 29, 30
Celsius 24, 25 hydroelectrical 147, 148
chemical potential energy 137, 142, 144, hypothesis 28, 29, 30, 31
145, 146, 154, 155, 156, 165
chlorophyll 97 I
chloroplast 97, 98 insects 44
chromatography 79, 84, 85, 93 invertebrate 42, 43, 44
classification key 36, 40, 44, 46
cold-blooded 43, 75, 77 J
condensation 75, 82, 83 joule 122

D K
dam kinetic energy 137, 139, 143, 144, 145,
density 7, 10, 22, 26, 53, 57, 59 146, 148, 151, 152
digestion 79, 82, 83
distillation 77, 78, 81 L
fractional 64, 65 laboratory 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 25, 33
dissolve 62 -gas burner 6, 8, 9
diversity 40 length 10, 14, 16, 17, 18, 19, 21, 25, 31, 33
dynamo 144, 166
Index 173

lubricate 115 R
luminous 8, 9 renewable 147, 153, 154
non- 8, 9 reptile 43
residue 79, 80, 81, 85
M
magnetic force 116 S
magnification 95 salt 61, 62, 64, 67, 72, 77, 81, 83
mammal 43 science 1, 2, 3, 4, 5, 8
mass 52, 111, 121 scientific method 28
measuring 1, 7, 10, 11, 12, 13, 14, 15, 16, solute 77, 78, 81
18, 19, 20, 21, 22, 24, 27, 28, 29, 30, 31, solution 77, 82
34, 35 solvent 59, 83, 84, 87
-cylinder 7, 14, 18, 19, 20, 21, 27, 29, 31, system 101, 102, 103
34, 35
melting 76, 77 T
-point 57 temperature 10, 24, 25, 57
meniscus 14, 19, 24, thermometer 24, 25
metre 124, 125 tidal energy 147, 152
microscope 93, 94, 95, 96, 97, 104 time 10, 12, 13, 28, 54, 55, 56, 64
minute 56 tissue 101, 103
mollusc 43, 44 turbine 87, 131, 140, 145, 148, 149, 151,
myriapod 44 152

N V
natural gas 134, 136, 143, 147, 153 vacuum 151
newton 121, 124, 125 vacuole 96, 97, 98, 104
nuclear energy 147, 151 vertebrate 42, 43
nucleus 96, 97, 98 virus 96, 97, 98
nutrition 37, 39 volume 52, 53

O W
oil 115 warm-blooded 43
crude 52, 64, 65 water 52, 55, 58, 59, 61–63, 64, 66
organ 100, 101, 102, 103 weight 111, 121, 123, 125, 127
organism 39, 40, 94, 99 wind energy 147, 151
micro- 45 work 122, 123

P
pascal 124
potential energy 137, 138, 142
pressure 109, 124, 125, 126, 127

174 Index

Chapter Drugs

9 Drugs are substances that affect the way our bodies work.
Some people abuse drugs and this can be harmful to their
health. Drug abuse is a serious problem because the
consequences affect drug users as well as their families. For
these reasons, the government has classified certain drugs as
‘controlled drugs’, and abusing and/or selling them is illegal.
In spite of this, drug abuse continues to be a problem.

Firman Allah Subhanahu Wa Ta’ala
Tafsirnya:
Sesungguhnya syaitan itu mahu
menimbulkan permusuhan dan
kebencian di antara kamu dengan
sebab (meminum) arak dan (bermain)
judi dan menghalangi kamu daripada
mengingati Allah dan mengerjakan
sembahyang, maka tidakkah kamu
mahu berhenti (daripada melakukan
perbuatan keji itu)? (91)

Shaitan (Satan) wants only to incite
enmity and hatred between you with
intoxicants (alcoholic drinks) and
gambling; and to hinder you from
the remembrance of Allah and from
As-Salat (the prayer). So, will you not
then abstain? (91)

(Surah Al-Maidah: 91)

Let’s Explore

• What is a drug?
• Which drugs are useful to us?
• Which drugs are harmful to us?
• What are the consequences of

abusing drugs?

Drugs 1

9.1 The Uses and
Abuses of Drugs

You should be able to:
• state the definition of drugs as any substance which,

when taken into the body, affects the way the body and
the brain work;
• describe some uses of drugs;
• list some commonly abused drugs – heroin, cannabis,
methylamphetamine and alcohol;
• list some signs and symptoms shown by a person
addicted to:
i) heroin,
ii) cannabis,
iii) methylamphetamine, and
iv) alcohol.

What is a drug?

A drug is any substance which, when taken into the body,
affects the way the body and the brain work.
A drug may be beneficial to the body or harmful to it
depending on how we use it. Drugs can be used in many
ways. A common example of a drug is caffeine. It is present
in tea, coffee, chocolates and some soft drinks.

Medicine Alcohol Coffee
Examples of drugs around us

2 Drugs

Medicinal drugs
Medicinal drugs are drugs normally prescribed by a
doctor. They are used to prevent or cure diseases. They
can also be used during surgery and to relieve pain.
Antibiotics, painkillers and anaesthetics are examples of
medicinal drugs.

Various medicinal drugs Science Smart

Antibiotics
Antibiotics are chemicals that are widely used to treat
many infectious diseases caused by bacteria. Diseases
such as pneumonia, tuberculosis and cholera are treated
using antibiotics.

Penicillin

Penicillin is a prescribed antibiotic. In 1928, Sir
Alexander Fleming
It is important to complete the course of antibiotics observed that the
prescribed by your doctor, even though you feel better. This bacteria he was
ensures that all the infection-causing bacteria are killed. If cultivating on an
these bacteria are not killed, they may become resistant to agar plate could be
the antibiotics. This can cause you to fall ill again. killed by the mould
Antibiotics are not used to treat diseases such as colds and Penicillium notatum.
inf luenza, which are caused by viruses. If your doctor prescribes This led to his
antibiotics when you have a cold or inf luenza, it is to prevent discovery of the f irst
a secondary bacterial infection. antibiotic, Penicillin.

Drugs 3

Painkillers
Painkillers are also known as analgesics. These drugs relieve
pain without causing numbness or affecting consciousness.
Common examples are paracetamol and aspirin. Aspirin is a
stronger painkiller and should only be prescribed by a doctor.

Paracetamol relieves minor pain and
reduces fever.

Anaesthetics
Anaesthetics are drugs that cause temporary loss of sensation,
making the body unable to feel pain. They are often used
in surgeries. Cocaine was the f irst known anaesthetic that
caused a loss of sensation in the area where it was injected.

4 Drugs Anaesthetics administered to a patient

Nowadays, a similar compound called Novocain, is used. It is
used in dental procedures such as tooth extractions.

Drug abuse
Drug abuse is the excessive consumption of drugs. This is
harmful to the body and has become a very serious problem
in many countries. Some common drugs of abuse are heroin,
cannabis, methylamphetamine and alcohol.
Drug abusers can become addicted. They become dependent
on the drug and feel that they cannot function normally
without it.
Heroin
Heroin is made from the opium poppy plant.

Opium poppy plants

Heroin abuse is one of the biggest addiction problems in many
countries. It slows down the proper functioning of the nervous
and respiratory systems.
Drug abusers who are addicted to heroin display the following
signs and symptoms:
• tiredness,
• loss of appetite, and
• very quick addiction to the drug.
Heroin overdose can be fatal as it can cause failure of
the respiratory system. Heroin that is injected into the
bloodstream causes collapsed veins, liver disease and
respiratory complications.

Drugs 5

Cannabis
Cannabis is also known as marijuana. It is obtained from the
leaves and f lowers of the Indian hemp plant.

Indian hemp plant

Drug users who abuse cannabis display the following signs
and symptoms:
• dry eyes and mouth,
• increased hunger,
• suffer from hallucinations – that is, they may be seeing

things that are not there, and
• appear sleepy.

6 Drugs

Methylamphetamine
Methylamphetamine is one of the most commonly abused
drugs in Brunei Darussalam. It is a colourless and odourless
solid which easily dissolves in liquids such as water and alcohol.
During the 1950s, it was used to treat depression and f ight
fatigue in World War II soldiers. However, scientists soon
discovered that methylamphetamine was harmful. Following
this discovery, it was no longer used as a medication.
Drug abusers who are addicted to methylamphetamine display
the following signs and symptoms:
• increased breathing and heart rates,
• dilated pupils, and
• loss of appetite.
Prolonged use of methylamphetamine has been linked to
mental illnesses and occasional death from heatstrokes, f its
or heart attacks.

Methylamphetamine crystal

Methylamphetamine is also known as ice due to its similar
appearance to ice. Locally, it is also known as syabu.

Drugs 7

Alcohol
Another abused substance is alcohol. It is a depressant that
slows down brain function. Alcohol is found in many drinks such
as beer, wine and brandy. Under Islamic law, the consumption
of alcohol is considered haram.
Here are some signs and symptoms that indicate a person is
addicted to drinking. An alcoholic may display:
• slurred speech,
• blurred vision,
• clumsiness or an inability to walk steadily, and
• withdrawal symptoms when deprived of alcohol.

Drinks such as wine
contain alcohol.

Alcoholics may lose control of their lives as they become
dependent on alcohol.

Quick Check

1. Which plant does heroin come from?
2. State two effects of taking cannabis.
3. State three possible health risks from taking

methylamphetamine.
4. How does alcohol affect the brain?

8 Drugs

9.2 Harmful Effects of
Drugs

You should be able to:
• explain the harmful effects of sports drugs, for example,

steroids and human growth hormones;
• state the consequences of drug abuse in relation to

addiction, crime and transmission of AIDS;
• discuss the harmful effects of excessive consumption of

alcohol (including the effects on families and society);
• show an awareness of the presence of harmful chemicals in

cigarette smoke;
• state the harmful effects of nicotine, tar and carbon

monoxide;
• explain the harmful effects of active and passive smoking;
• suggest ways of encouraging the public to refrain from

smoking.

Sports drugs Science Smart

Sports drugs are substances used by people to improve Farmers often inject
their performance in sports. Anabolic steroids and human their beef cattle
growth hormones are drugs that are taken by some athletes with steroids or
to build up their bodies and to enhance their performance. growth hormones to
It helps them increase muscle mass and performance in increase body mass.
activities like weightlifting, sprinting and other athletic events. It is thought that
these steroids and
Sports organisations ban the use of sports drugs for the hormones pass to
following reasons: humans when the
• health risks of performance-enhancing drugs, beef is eaten.
• equal opportunity for all participating athletes, and
• to portray the image of ‘clean’ sports to the public.

As with all drugs, the prolonged use of steroids and growth
hormones can have harmful side effects. Some of these
effects include:
• aggression,
• hair loss/baldness,
• acne,
• liver damage, and
• infertility.

Drugs 9

Consequences of drug abuse

There are many consequences of drug abuse. It can lead to
addiction, crime, and the transmission of diseases such
as Acquired Immune Def iciency Syndrome (AIDS).

Addiction
Drug abuse may result in addiction. Getting out of the drug
habit is diff icult. Addicts crave the drugs, even after they
have stopped using them. They will experience withdrawal
symptoms.

Withdrawal symptoms include:
• restlessness,
• excessive sweating,
• uncontrollable shaking,
• anxiety,
• fever, and
• headaches.

Drug abuse can cause mental
illness. Drug addicts:
• are very depressed most of

the time, and
• may also suffer from

hallucinations.

Science Smart A common withdrawal
symptom is anxiety.
How to avoid getting addicted to drugs
1. Don’t be ‘daring’ or ‘curious’ and try Say No to Drugs

drugs. Remember, there is no virtue or
esteem in using drugs.
2. If you have a particular problem, drugs
will not help you solve it. Discuss it with
friends and family.
3. Keep physically active with sports,
clubs or societies in the community
or at school.
4. Remember, drug abuse is illegal and
there are severe penalties for drug
abuse and drug traff icking.
5. If you suspect that someone is peddling
or abusing drugs, you can contact the
Narcotics Control Bureau.

10 Drugs

Continued abuse of drugs can lead to irreversible damage to
various body organs.

Drugs affect the brain and the central
nervous system. Persistent use can result
in behavioural changes and brain damage.
The brain controls the rate at which the
heart beats, so drugs that affect the brain
can lead to heart problems.
Drugs can be inhaled. This can cause lung
damage or even lung cancer.
In the process of breaking down alcohol,
liver damage may occur due to the
poisonous nature of alcohol.
Drug abuse can result in kidney failure.

The harmful effects of drugs on the body

Crime
Over time, addicts will require more and more of the drug to
achieve the same effects. Drugs are expensive and addicts
often resort to crime such as theft to obtain the money they
need to buy drugs. Their dependence on drugs could also lead
to violence towards their family members if the drug user is
prevented from obtaining drugs.

Drugs 11

Try this Transmission of diseases
Some drugs are taken through injections. Viruses, which cause
Collect newspaper diseases such as Hepatitis C and AIDS, can be passed from
clippings describing one person to another if needles are shared.
problems caused
by drug abuse. Law on drugs
Discuss these with The Narcotics Control Bureau of Brunei Darussalam is
your teacher and responsible for enforcing the Misuse of Drugs Act and any
classmates. Write relevant laws that are related to drug abuse.
your opinion on them
and make a bulletin Quick Check
board display with
these clippings. What are the withdrawal symptoms of drug abuse?

WB Link Activity 9.1 Harmful effects of alcohol

Science Bites Alcohol consumption has many harmful effects on the body,
families and society.
In most countries, • Effects of alcohol on the body
police off icers use When alcohol is consumed, it is broken down in the liver.
portable breath-
analysers to f ind out Prolonged alcohol abuse may damage the liver. Liver failure,
if a driver’s blood if not treated in time, may eventually cause death.
alcohol level is above • Effects of alcohol on families
the legal limit. If people drink alcohol frequently, they can become addicted.
They may neglect their work and families. Alcohol may cause
them to become aggressive and exhibit violent behaviour
towards others.
• Effects of alcohol on society
Some alcoholics may even commit crimes to obtain the drink
they need.
Driving under the inf luence of alcohol may cause road
accidents as the driver’s judgement will be impaired. The
driver may drive faster with less caution and underestimate
the speed of the vehicle. The driver’s reaction times
are slower.

Driving under the influence of alcohol
can result in road accidents.

12 Drugs

Tobacco

Tobacco is a product from the leaves of the tobacco plant. It
is dried and then used to make cigarettes.

The dried leaves of a tobacco plant

Many teenagers (and even adults) consider smoking
fashionable. However, when a person smokes, a lot of harmful
substances get into the body.

Cigarettes cause harm to various parts of
our body.

There are more than 4,000 substances in cigarettes. Some of
these substances are harmful. They can cause heart diseases
and lung cancer. Smokers may also suffer from bronchitis.
A person suffering from bronchitis will cough badly and often
have diff iculty breathing.

Drugs 13

Science Bites Harmful substances in cigarettes

Cigarette packs often The effects of smoking on health are serious and may even
have warnings on cause death. This is due to the many harmful substances found
the consequences of in tobacco. The most harmful substances found in cigarette
smoking printed smoke are tar, nicotine, carbon monoxide and irritants.
on them.
Tar
It is a brown, sticky substance that builds up in the lungs
during smoking. Tar causes the following harmful effects:
• damages the cilia in the throat,
• damages the cells in the lungs – this decreases the oxygen

supply to the bloodstream, and
• causes lung cancer.

Nicotine
Nicotine is an addictive substance found in tobacco. This gives
the smoker the urge to smoke more. It causes harmful effects
such as:
• blood clotting,
• increased blood pressure,
• headaches, and
• damage to the heart and blood vessels.

Carbon monoxide gas
It is a poisonous gas. It reduces the capacity of blood to take
in oxygen from the lungs.

Irritants
Cigarette smoke contains substances that irritate the cells
in the lungs. This causes smokers to cough. Prolonged
smoking habits can lead to a lung disease called emphysema.
This disease damages the lungs and makes the smokers
feel breathless. Irritants can also cause cancer.

WB Link Activity 9.2 Smoking is harmful to our health.
14 Drugs

Harmful effects of active and passive smoking
Did you know that cigarettes do not just harm smokers?
When someone smokes near you, you breathe in the harmful
substances. This is called passive smoking.
Passive smoking by pregnant women can affect the mental
and physical development of the foetus. This may lead to a
miscarriage or a stillborn child.
There are many diseases caused by active and passive smoking.

Cancer
Studies have shown that the more you smoke, the greater the
risk of getting lung cancer.

The image on the left shows the lungs of a non-smoker and WB Link Activity 9.3
the image on the right shows the lungs of a smoker.

Smoking also increases the risk of cancers of the mouth,
throat, pancreas, kidneys and urinary bladder.

Drugs 15

Chronic bronchitis
In chronic bronchitis, the cells in the main air passages to
the lungs become inflamed. Excessive mucus is secreted. This
reduces the airflow in the air passages, making breathing
difficult. The person coughs and wheezes persistently to clear
the air passage. This makes the lungs more likely to be infected
by bacteria.

Emphysema
Emphysema is commonly associated with chronic bronchitis
and smoking. The intense coughing causes the air spaces
to enlarge and decreases the surface area of the lungs.
This reduces the absorption of oxygen. An affected person
spends a lot of energy just to keep breathing and can suffer
breathlessness during exertion.

Smoking control measures in Brunei Darussalam
Brunei Darussalam has introduced measures to discourage
people from smoking. This includes observing the ‘World No
Tobacco Day’ on 31 May every year, increasing the price of
cigarettes and the prohibition of smoking in public places.
Tobacco products are tightly controlled, cigarette packets carry
health warnings and the sale of cigarettes to minors is illegal.
The Tobacco Act of Brunei Darussalam was enforced from
1 June 2005.

Ways to refrain from smoking
Here are some ways to help people stop smoking:
• Educate them on the harmful effects of smoking.
• Place health warnings on cigarette packets.
• Stop people from smoking in public places such as

restaurants, offices, lifts and on public transport. Smoking is
not allowed on all Royal Brunei Airlines flights.
• Display ‘No Smoking’ signs in public places to discourage
people from smoking.
• Stop tobacco companies from advertising, especially in
magazines and over television.
• Educate your family members and friends on the dangers
of smoking.
• Get involved in healthy activities such as sports and
community service.

‘No Smoking’ signs
are displayed in public
places to discourage
smoking.

16 Drugs

Participate in sports and join clubs in school.

Take part in community activities

Quick Check

1. What do anabolic steroids do?
2. State two harmful effects of consuming too much alcohol.
3. State two harmful effects of smoking.
4. What measures is Brunei Darussalam taking to

discourage smoking?

Drugs 17

Summary Drugs can be divided into

are Medicinal drugs

Any substance Antibiotics Painkillers Anaesthetics
which, when taken
into the body, affects
the way the body
and brain works

For treatment Relieves pain Causes a
of bacterial without causing temporary loss
infections numbness of sensation

18 Drugs

Drugs of abuse

Heroin Methylamphetamine Anabolic Cigarettes
steroids
(human growth • Contain tar,
hormones) nicotine,
• Tiredness • Increased carbon
• Loss of breathing and monoxide and
appetite heart rates irritants
• Very quick • Dilated pupils • Used to build can lead to
• Loss of appetite up muscle
addiction tissue • Miscarriage or
to the drug stillborn child
• Can be in pregnant
abused as a women
Cannabis Alcohol sports drug
• Lung cancer
• Causes • Cancers of
increased
• Dry eyes and • Slurred speech aggression the mouth,
mouth • Blurred vision and male throat,
• Clumsiness infertility pancreas,
• Increased • Inability to kidneys
hunger walk steadily and urinary
• Hallucinations bladder
• Appear sleepy • Withdrawal • Chronic
symptoms bronchitis
addiction when deprived • Emphysema
leads to of alcohol

• Irreversible damage excessive
to body organs
• Crime consumption
• Transmission of can lead to

diseases through • Liver damage
needle-sharing
• Violence and
quarrels within
the family
• Crime

• Restlessness withdrawal symptoms
• Excessive sweating
• Uncontrollable shaking
• Anxiety
• Fever
• Headaches

Drugs 19

Review Questions

1 What are medicinal drugs used for?
A To help cure illnesses
B To help you run faster
C To be accepted by others
D To escape from your problems

2 Which of these drugs comes from the tropical hemp plant?
A Heroin
B Nicotine
C Cannabis
D Methylamphetamine

3 Which of the following drugs causes hallucinations?
A Aspirin
B Caffeine
C Cannabis
D Anaesthetics

4 Which of the following diseases can be transmitted by sharing
contaminated needles?

A AIDS
B Cancer
C Diabetes
D Hypertension

5 Which of these chemical substances found in cigarettes is responsible
for the addictive effect of smoking?

A Tar
B Nicotine
C Irritants
D Carbon monoxide

6 In which of these illnesses can smoking be a contributing factor?
A Inf luenza
B Diabetes
C Lung cancer
D Kidney failure

20 Drugs

7 What is a drug?
8 Name two types of medicinal drugs that you have studied and state

their uses.
9 What are the side effects of steroids?
10 State two harmful effects of:
a) using heroin.
b) smoking.
11 State three harmful effects of alcohol consumption.
12 Discuss some social problems caused by drug abuse.

Drugs 21

Chapter Gases

10 Earth’s atmosphere consists of several gases in varying amounts.
Most of these gases are essential for maintaining life on Earth.
What gases are found in the air we breathe? What are the
properties of these gases?

Firman Allah Subhanahu Wa Ta`ala
Tafsirnya:
Allah jualah yang menghantarkan angin,
lalu angin itu menggerakkan awan,
kemudian Allah menyebarkan awan itu
di langit sebagaimana yang
dikehendaki-Nya dan menjadikannya
berkelompok-kelompok, lalu engkau
melihat hujan keluar dari celah-celahnya.
Maka, apabila Allah menurunkan hujan
itu menimpa sesiapa yang dikehendaki-
Nya daripada hamba-hambaNya,
mereka serta merta bergembira. (48)

Allah is He Who sends the winds, so that
they raise clouds, and spread them along
the sky as He wills, and then break them
into fragments, until you see rain drops
come forth from their midst! Then when
He has made them fall on whom of His
slaves as He wills, lo, they rejoice! (48)

(Surah Ar-Rum: 48)

Let’s Explore

• What is air made up of?
• What are the properties of the

gases in air?
• What are the uses of the gases

found in air?
• How can we identify oxygen,

carbon dioxide, water
vapour and hydrogen?
• What are the properties and uses
of hydrogen?

22 Gases

10.1 Gases in the Air

You should be able to:
• list the approximate composition of gases in the air, by

percentage (%):
i) nitrogen is 79%,
ii) oxygen is 20%,
iii) carbon dioxide is 0.03%,
iv) noble gases are around 1%, and
v) water vapour varies.
• carry out investigations to show:
i) the percentage of oxygen in the air, and
ii) air contains water vapour.

Composition of air

Air is a mixture of gases. The gases found in air are:
• nitrogen (79%),
• oxygen (20%),
• carbon dioxide (0.03%),
• noble gases (≈1%: helium, neon, argon, krypton, xenon

and radon), and
• water vapour.

Carbon dioxide
0.03%

Noble gases
≈ 1%

Oxygen
20%

Nitrogen 79%

Composition of dry air

Water vapour is not included in the composition of air. This
is because its proportion varies. In humid countries like
Brunei Darussalam, there is a higher percentage of water
vapour in air.

Gases 23

Balancing oxygen and carbon dioxide

The composition of these gases remains almost constant. The
air will not run out of oxygen and carbon dioxide. This is due
to the oxygen and carbon dioxide cycle.

Plants and animals use Carbon dioxide from the
oxygen during respiration. atmosphere is used up by
During plant growth, the plants during photosynthesis.
rate of photosynthesis
is higher than the rate Carbon dioxide is
of respiration. This way, released by animals
plants produce more and plants during
oxygen than they use. respiration.

Oxygen and carbon dioxide cycle

Quick Check

1. State the composition of the following gases found
in air:

a) nitrogen, b) oxygen,

c) carbon dioxide, and d) noble gases.

2. How does the composition of oxygen and carbon dioxide
in the air remain constant?

24 Gases