LOWER SECONDARY SCIENCE TEXTBOOK

Chapter Introducing
Science
1
The study of Science helps us to understand the world around
us. Scientists carry out research and conduct experiments
using various scientific techniques and equipment to obtain
knowledge about the world.

Firman Allah Subhanahu Wa Ta’ala
Tafsirnya:
Dia menyinsingkan sinar pagi dan
menjadikan malam untuk beristirehat
serta (menjadikan peredaran)
Matahari dan Bulan untuk mengira
waktu. Yang demikian itu adalah
ketentuan Allah Yang Maha Perkasa
lagi Maha Mengetahui.

(He is the) Cleaver of the daybreak.
He has appointed the night for
resting, and the Sun and the Moon
for reckoning. Such is the measuring
of the All-Mighty, the All-Knowing.

(Surah al-An’âm: 96)

Let’s Explore

• What is Science?
• What are the various scientific

techniques and equipment that
scientists use?
• How do we carry out a scientific
investigation to solve a problem?

1Introducing Science

Introducing Science

The study of Science helps us to understand the things we see
around us and how they affect our lives. Look at the things
around you. How has Science helped to improve them? Below
are some questions that you might ask.

Wfrohmy caa dni sIt asnmcee?ll durians abWneh tawantei meanrae la tc hpeellal ?dnitf fceerell nacneds

How are these girls able hBHeuaontws w enad toeb ruI?r nuesre toa
to walk without slipping?

2 Introducing Science

1.1 Laboratory Safety Rules

You should be able to:
• state basic laboratory safety rules;
• identify hazard warning symbols;
• explain first aid treatments in common laboratory mishaps.

Laboratory work is your chance to explore Science first-hand.
It can be fun and exciting but certain precautions must be
taken to prevent harm or injury. Listen closely when your
teacher explains all the laboratory safety rules.

Laboratory rules

Here are the 12 most important rules to bear in mind.

1. Listen to and follow 2. Always handle equipment 3. Do not eat or drink
instructions given by your properly. while in the laboratory.
teacher.

4. Do not run or play in the 5. Wear safety goggles when 6. Do not place books or
laboratory. handling, mixing and pieces of paper near a flame.

heating chemicals.

7. Do not pour used 8. Do not dispose of corrosive 9. Do not point the mouth of a
solutions back into liquids and solid waste in test tube at another person
the bottle. the sink. during heating. The substance
in the test tube may

shoot out.

10. Always wash your 11. Do not tamper with 12. In the event of a fire,
hands thoroughly electrical sockets. follow the standard
before and after laboratory
every practical
lesson. evacuation
procedure.

3Introducing Science

Hazard symbols

Some of the chemicals that you use in the Science laboratory
are potentially harmful. Hazard symbols are used to label
such chemicals to warn you of the possible dangers. Here
are some common hazard symbols to look out for.

Explosive Toxic
This substance will react violently This substance is harmful
when heated or struck. in small doses.
Examples: sodium metal, Examples: methanol,
hydrogen peroxide. potassium cyanide, mercury,
Flammable carbon monoxide, chlorine.
This substance catches f ire easily. Corrosive
Examples: petrol, kerosene, This substance will corrode
alcohol, hydrogen. (eat away) other substances.
Irritant Examples: sulfuric acid,
This substance produces potassium hydroxide,
vapours or fumes that irritate calcium oxide.
the skin, eyes, nose and throat. Biohazardous
Examples: phenol, chloroform. This is a poisonous substance
Radioactive of a biological nature.
This substance emits harmful Examples: some medical
radiation. waste, microorganisms,
Examples: plutonium, uranium. viruses, toxins.

WB Link Activity 1.1
4 Introducing Science

When accidents occur

When you are in a Science laboratory, accidents may occur. Report
any accident (spill, breakage, etc.) or injury (cut, burn, etc.) to your
teacher immediately, no matter how minor it may appear. Below are
some f irst aid treatments for common laboratory mishaps.

For mild burns and scalds, cool the affected
area with running water for at least 5 minutes.
Do not use very cold water or ice cubes.

If any substance gets into your eyes, go to the
nearest eye wash station and rinse to clear
the irritation in your eyes. Avoid rubbing your
eyes. Rubbing the eyes can spread or worsen
the contamination.

For minor cuts or scrapes, wash the area with
mild soap and clean water. Dab some hydrogen
peroxide to disinfect the area after washing it
clean. Apply some antibiotic ointment on the
cut to prevent germs from infecting the wound.
These supplies may be obtained from the f irst
aid kits in your laboratory.
All laboratories are equipped with a f ire extinguisher, f ire sand
bucket and f ire blanket to put out a f ire.

Quick Check

1. What is Science?
2. State three laboratory

safety rules that
you should observe
while carrying out an
experiment.
3. What should you do when
an irritable substance
gets into your eyes?
4. Name two hazard
symbols and an example
of each hazard.

5Introducing Science

1.2 Handling Common
Laboratory Apparatus

You should be able to:
• identify common laboratory apparatus;
• state the functions of common laboratory apparatus;
• draw cross-sectional diagrams of common laboratory apparatus;
• identify and state the function of the different parts of

laboratory gas burners;
• demonstrate the proper technique of lighting a Bunsen or

laboratory gas burner.

? In addition to the laboratory safety rules, you will also come
across some common apparatus in the laboratory. Each of
What other apparatus them is designed for a particular use.
can you think of?
Apparatus

Below are some common laboratory apparatus.
Learn to use them correctly and carefully.

Apparatus Functions Apparatus Functions
Filter funnel Beaker
• For transferring • For containing
Test tube liquids into chemicals
containers with a
small opening • For collecting and
holding liquids
• For separating solids
from liquids by using Boiling tube • To boil liquids during
f ilter paper experiments

• For containing
small amounts of
chemicals

• For mixing or heating
solutions or liquids

Conical flask • For containing and Evaporating dish • To evaporate the
mixing chemicals and liquid in a solution
liquids to produce over a Bunsen
gas when heating is burner
not required

6 Introducing Science

Apparatus Functions Apparatus Functions
Wire gauze Tripod stand • For supporting
• To spread the heat
of a flame apparatus during
heating
• To support beakers
being heated by a
Bunsen burner

Measuring cylinder • To measure volumes Dropper • To add a small
of liquids volume of liquid,
drop by drop

Glass rod • To stir chemicals in Test-tube holder • To hold test tubes
Glass rod the laboratory

Common laboratory apparatus

Laboratory apparatus can be represented by drawing their Science Smart
outlines or the cross-sections.
Draw clear cross-
sectional diagrams to
represent apparatus
set-ups, instead of
drawing 3D diagrams.

Filter funnel Beaker Test tube Evaporating dish
Wire gauze

Tripod stand

Boiling tube Conical flask WB Link Activity 1.2
7Introducing Science
Cross-sectional diagrams of common laboratory apparatus

Laboratory gas burners

Laboratory gas burners are important pieces of apparatus in
the Science laboratory. We need to know how to use them
properly. The most common laboratory gas burner is called
the Bunsen burner.

Gas knob

Air-hole: to allow Barrel: to allow air
air to enter the and gas to mix
burner
Collar: to open or close
the air-hole to control
the amount of air
entering the burner

Super Scientist Different parts of a Bunsen burner

Robert Bunsen Steps to light a laboratory gas burner
(1811–1899), a
great German Step 1: Turn the collar to make sure that the air-hole
chemist, developed is closed.
the Bunsen burner.
Step 2: Light a match.
Step 3: Hold the lit match over the top of the barrel.
Step 4: Turn on the gas to obtain a luminous flame.
Step 5: Slowly open the air-hole to obtain a non-luminous

flame for heating.

8 Introducing Science

Barrel Air-hole
Collar Gas knob

Gas cartridge

As you adjust the air-hole of a laboratory gas burner, you will
realise that it will give out two different types of f lames; a
luminous f lame and a non-luminous f lame. The table below
shows the differences between the two types of f lames.

Air-hole Fully closed Open

Type of f lame Luminous Non-luminous

Colour of f lame Orange Blue

Flow of f lame Unsteady Steady

Produces soot Yes No

Degree of hotness Hot Hotter than luminous f lame

Differences between a luminous flame and a non-luminous flame

Quick Check WB Link Activity 1.3

1. Identify two pieces of common laboratory apparatus
and state their functions.

2. State the function of a boiling tube.
3. Identify and state the functions of the parts of a

Bunsen burner.
4. Write down the steps involved in obtaining a

luminous f lame.

9Introducing Science

1.3 Measurements

You should be able to:
• describe the limitations of human sense organs and thus the

need for measuring instruments;
• demonstrate the correct way of taking a measurement;
• record measurements using the correct units;
• state the S.I. units for mass, time, length and temperature;
• perform inter-conversion of units.

All experiments performed in a laboratory require one or more
types of measurements. Typically, we measure three simple
quantities — mass, length and time. Occasionally, we include
area, volume, density and temperature.
We often take measurements in our daily lives. Can you
think of some examples? Why do you think it is important to
take accurate measurements and use standard units? Let us
f ind out.

In ancient times, one cubit was the No, wait! Ali’s arm is
length from the elbow to the tip of the even longer. Let’s buy
person’s hand. Why do you think people from him instead!
have stopped using such methods today?

What a long arm!
We’ll get a good deal
at Ahmad’s stall!

Limitation of sense organs The above scenario shows the importance of the standard unit
of length. The standard units of measurements allow us to
10 Introducing Science take accurate measurements.

Since 1960, scientists from different parts of the world have
agreed to the International System of Units, also known
as S.I. units. Some common S.I. units are shown in the
table below.

Physical quantity S.I. unit Symbol
Mass kilogram kg
Time second s
Length m
metre
Temperature kelvin K

Common S.I. units

Measuring mass Science Smart

Mass is the measurement of the amount of substance in a body. Remember not to
The S.I. unit of mass is kilogram (kg). Another commonly miss out units in
used unit for mass is gram (g). your presentation of
numerical answers.
Man
70 kg 11U tskoegn fn=uel 1c=0o 01n00v 0ge0r skigons

Boy
25 kg

Cat Basketball
5 kg 500 g

Frog
40 g

Comparing the masses of different objects

Instruments used to measure mass
We can measure mass using equipment such as the
triple-beam balance and electronic balance.

Triple-beam balance Electronic balance ?

If we have two
identical balloons and
one is f illed with air
while the other is f illed
with an equal volume
of water, will their
masses be the same?

11Introducing Science

Science Smart Measuring time

Learn how to convert Before watches and clocks were invented, people depended on
days, weeks, months ancient methods of measuring time. Commonly used objects
or years into seconds were the hourglass, sundial and water clock.
and hours.

Hourglass Sundial Water clock

However, these did not produce accurate measurements.
Over the centuries, Man has developed more accurate ways
of measuring time. The S.I. unit of time is second (s). Other
units of time include the minute (min), the hour (h) and the
millisecond (ms).
Instruments used to measure time
Watches and clocks are everyday instruments used to measure
time. Most watches and clocks measure time to the nearest
second. However, these were not accurate enough for scientif ic
purposes such as measuring how fast a gas is given off during
a chemical reaction.

Mechanical stopwatch Electronic stopwatch Clock

12 Introducing Science

The electronic stopwatch is more accurate than the mechanical
stopwatch. It can measure time intervals accurate to 0.01 s.
Being able to keep track of time is very important to many
people, especially in sports.

I111n1 m tmhde sair=n y-= c=6= o00 n6. 20m0v40 e is1nhr ossuiorns s

The electronic stopwatch is used to measure
a short period of time.

In addition to stopwatches and
clocks, stop clocks are also used
to measure time. A stop clock is a
larger version of the stopwatch. Its
advantage over a stopwatch is that
it is not hand-held and allows more
than one person to read the time.

Chess stop clock Laboratory stop clock

Quick Check WB Link Activity 1.4

1. What is mass?
2. What is the S.I. unit of mass?
3. Name two instruments used to measure mass.
4. What were the ancient instruments of measuring time?
5. What are the modern instruments of measuring time?
6. Give examples of situations in which you need to

measure time accurately.
7. What is the S.I. unit of time?
8. What are some other units of time?

13Introducing Science

1.4 Length, Area
and Volume

You should be able to:
• measure length correctly using appropriate instruments;
• state the S.I. units of length, area and volume;
• calculate the area and volume of objects with regular shapes;
• estimate the area of objects with irregular shapes;
• read volume using the meniscus level of a measuring cylinder;
• calculate the volume of an object with regular shape;
• measure the volumes of irregular shaped objects using the

displacement method.

Measuring length

In this section, we are going to look at the measurement of
length. Is it enough to use a ruler to measure all lengths?
Length is the distance between two specified points.
The S.I. unit of length is metre (m). Other units of length
include the centimetre (cm) and millimetre (mm).
Measurements of length include measurements of height,
depth, width, thickness and diameter.

Instruments used to measure length
Two examples of common instruments used to measure length
are the ruler and the measuring tape.

Ruler
A ruler is commonly used in the laboratory. The following tells
you how to measure the length of an object correctly.

Position B Taking a correct reading
Reading = 0.8 cm
Step 1: Place the side of your ruler against
Position A Position C the object you wish to measure.
Reading = 0.7 cm Reading = 0.9 cm
Step 2: Look at the ruler right above the
point you wish to read.

Step 3: Make sure that the zero mark of
the ruler is directly above the point
you wish to start measuring from.

Object Ruler When your eye is in the wrong position for
reading off the ruler, you may get what
14 Introducing Science is called a parallax error. Reading from
positions A and C will result in a parallax
error. Position B is the correct position from
which to take your reading.

Measuring tape
When you have lengths greater than 1 m, a measuring tape
can be used. Measuring tapes come in different lengths —
some can be as long as 60 m.

Measuring tapes

External and internal callipers
It may be diff icult to measure the external diameter of a
round object using a ruler or measuring tape. Instead, we can
use external callipers. To measure the internal diameter of
objects, internal callipers can be used.

0 cm 1 2 3 4 0 cm 1 2 3 4

External callipers Internal callipers

Science Smart

Vernier callipers are used to measure short lengths and
diameters of objects up to 10 cm. Vernier callipers provide
a more accurate measurement than the ruler. The smallest
division on the vernier scale is 0.01 cm, whereas the
smallest division on the ruler is only 0.1 cm.

WB Link Activity 1.5

Activity 1.6

15Introducing Science

Measuring area

When we measure the space occupied by the surface of an
object, we are trying to f ind the area. The S.I. unit of area is
square metre (m2). Other commonly used units for area are
square centimetre (cm2) and square kilometre (km2).
Regular shapes
Squares, rectangles, triangles, circles and parallelograms are
all examples of regular shapes. We can calculate the areas of
regular shapes by using the right formulae.

aa h

a b b r h

Square Rectangle Triangle Circle b
Area = a × a Area = b × a Area = ␲r2 Parallelogram
Area = 1 × b × h
2 Area = b × h

Key Irregular shapes
a = length How about shapes like these below? Can you apply the above
b = obfr ebaadsteh or length formulae to f ind their areas?
h = height
␲ = 3.142
r = radius

The area of an irregular shape cannot be calculated using a
formula. However, we can estimate its area with the help of
square grids with sides of known lengths.

16 Introducing Science

For example, if the sides are each of 1 cm in length, the
area of each square is (1 cm × 1 cm) = 1 cm2. Each square
of 1 cm2 becomes our basic unit to f ind the area of the
shape. A grid paper can be used to trace the outline of the
surface area you wish to measure.

Step 1: Look at the shape on the right. The area of one A basic unit of area
square grid is 1 cm2. The irregular shape is traced
onto the square grid. 1 cm Key = 1 cm2
= 1 cm2
Step 2: The area within the irregular shape that takes up 1 cm = 0 cm2
half a square or more is ticked.

Step 3: The estimated area is calculated as the number of
ticked units multiplied by 1 unit’s area.

Estimated area = number of ticked units × 1 cm2
Count the total number of ticks
Number of ticks = 36
Thus, the estimated area of the irregular surface
= 36 ticks × 1 cm2
= 36 cm2

Try This

Use the grid below to estimate the area of the hand.
2 cm

2 cm

?

How can you get
a more accurate
estimation of the area
of the hand? Would
using smaller or larger
grids improve your
estimation?

WB Link Activity 1.7

17Introducing Science

Measuring volume

What is the difference between the book on the right and the
book on the left? One of them would occupy more space than
the other. This is because they have different volumes.

Science Smart The volume of an object is the amount of space it occupies.
The S.I. unit of volume is cubic metre (m3).
Other commonly Measuring volumes of liquids
used units for volume We can measure the volumes of liquids with a measuring
are cubic centimetre cylinder, a pipette or a burette.
(cm3), litre (l) and
millilitre (ml).

Measuring cylinder Pipette Burette

18 Introducing Science

Reading the meniscus
In narrow glass cylinders, the liquid level is curved into a
shape called the meniscus. For most liquids such as water,
the meniscus curves are as shown in the f igure below. Just
like reading the ruler, your eye should be at the correct level
to read the measuring cylinder. To get the correct reading,
make sure your eyes are at the same level as the bottom of
the meniscus to avoid parallax error.

100
90
80

70

70
60

60

50
40

30 Position your eye to take readings
20 at the bottom of the meniscus.
10 Water

Reading the meniscus

Measuring volumes of regular shaped solids
We can measure the volumes of regular shaped solids by using
the right formulae.

l h Key
hbl === h bleerneigaghdtthth
l b
l l
Cube Cuboid
Volume = l × l × l Volume = l × b × h

Measuring volumes of irregular shaped solids
Can you use the above formulae to calculate the volume of the
objects shown below?

19Introducing Science

Two types of displacement methods can be used to measure
the volume of a small, irregular solid.

? Method 1: Using a measuring cylinder 100
1. Observe and note down the level of water 90
If you wish to 80
measure the volume in the measuring cylinder. 70
of a stone but f ind Initial water level = 60 cm3 60
it too large to be 2. Tie the object onto the end of a piece 50
lowered into the 40
measuring cylinder, of string and lower it slowly until it is 30
what instrument completely submerged. Note the new 20
should you use water level. 10
instead?
New water level = 82 cm3 100
Hence, the volume of the object 90
= volume of water displaced by the object 80
= new water level – initial water level 70
= 82 – 60 60
= 22 cm3 50
40
30
20
10

Displacement can

Method 2: Using a displacement can (Eureka can) Spout

1. Fill a displacement can with water to the level of the spout. Allow
excess water to f low into a container. When the water stops f lowing,
replace the container with a dry, empty measuring cylinder.

2. Tie a piece of string to the object and lower it into the displacement
can until it is completely submerged. Some water is displaced into
the measuring cylinder. Note the volume of water displaced by the
object.

Hence, volume of the object = volume of water displaced by the object

? WB Link Activity 1.8

What is the
advantage of each
method shown?

20 Introducing Science

Conversion of units 1111l1 1 1 m1= mI h d knm lokai 1gntu=my eu=r=0 r =t10== e-1 1 0c c 20= 1o6 m04c0 0 nm00 6 3 hvc00m03ome 0 guisr nermsuscitooennsds
Example 1
Quick Check
Convert 24 km to m.
1. What are the S.I.
Solution units for measuring
1 km = 1 000 m length, area and
Multiply km by 1 000 to get m volume?
24 km = 24 x 1 000 = 24 000 m
2. Can you list other
Example 2 units for measuring
length?
Convert 45 cm to m.
3. What are the
Solution instruments
1 m = 100 cm commonly used to
Divide cm by 100 to get m. measure lengths
45 cm = 45 ÷ 100 = 0.45 m around us?

Example 3 4. How do we f ind the
Convert 50 g to kg. area of a rectangle?

Solution 5. How do we estimate
1 kg = 1 000 g the area of an
Divide g by 1 000 to get kg irregular shaped
50 g = 50 ÷ 1 000 = 0.05 kg object?

Example 4 6. How can we get
the correct reading
Convert 15 kg to g. from a measuring
cylinder?
Solution
1 kg = 1 000 g 7. How do we f ind
Multiply kg by 1 000 to get g the volume of an
15 kg = 15 × 1 000 = 15 000 g irregular solid?

Example 5 21Introducing Science
Convert 7 l to cm3.

Solution
1 l = 1 000 cm3
Multiply l by 1 000 to get cm3
7 l = 7 × 1 000 = 7 000 cm3

1.5 Density

You should be able to:

• def ine density; mass
volume
• use the formula: density = ;

• state that solids of the same substance have the same
density irrespective of shape and size;
• explain that different substances will have different densities;
• demonstrate that f loating depends on the density of matter
with reference to:
i) fl oating of a solid on a liquid and
ii) fl oating of a liquid on another liquid.

The density of a substance is def ined as the mass per
unit volume.

density = mass
volume

The S.I. units of mass and volume are kilogram (kg) and cubic
metre (m3) respectively. Hence, the S.I. unit of density is
kilogram per cubic metre (kg/m3). Another common unit
for density is g/cm3.

Example 1

A stone with a mass of 7 g, has a volume of 2 cm3.
Calculate its density.

Solution
Density = v mo lua ms s e = 2 7 c mg 3 = 3.5 g/cm3

Have you ever noticed that different objects of the same size
and volume can be heavy or light when you lift them?

For example, a 1 cm3 steel box has a mass of 7.8 g. Therefore,
the density of steel is 7.8 g/cm3. On the other hand, a
1 cm3 wooden box has a mass of 0.85 g. It has a density of
0.85 g/cm3. The density of steel is higher than the density
of wood, so we can say that steel is denser than wood, and
wood is less dense than steel.

22 Introducing Science

Floating and sinking
Have you noticed how some substances float while others sink?

How can the heavy block Hmmm, I think
of wood float but the
light paper clip sink? Teak block volume and mass
both play a part.

Water

Paper
clip

Look at the diagram above. We can see that the teak block
floats on water whereas the steel paper clip sinks in water.
Why is this so?

Substance Density Substance Density
(g/cm3) (g/cm3)
Teak block Aluminium
Cooking oil 0.85 Mercury 2.70
0.95 Rubber 13.60
Water 1.00 Steel 1.52
Sand 1.60 7.80

Densities of some common substances Oil is less dense than
water and will float
In general, a denser substance will sink while a less dense
substance will float. The teak block, being less dense than at the top.
water, floats in water. The steel paper clip, being denser than
water, sinks in water. From the table above, we can see that
the density of water is 1.00 g/cm3 and the density of teak
is 0.85 g/cm3. On the other hand, the density of steel is
7.80 g/cm3, which is more than the density of water. We can
conclude that the teak block, being less dense that water,
floats on water and that the steel paper clip, being denser than
water, sinks in water.

Using the values given in the table, can you list out the
substances that will float on water and substances that will
sink in water?

Quick Check WB Link Activity 1.9
23Introducing Science
1. What do you compare to determine if a substance
will sink or float in another substance?

2. Will the density of a substance change if its shape
is changed?

1.6 Temperature

You should be able to:
• define temperature;
• compare the differences between mercury and

alcohol thermometers.

Temperature is a measurement of the degree of hotness
or coldness.
The S.I. unit of temperature is kelvin (K). The commonly
used unit of temperature is degree Celsius (°C).
Earlier, we discussed how accurate measurements cannot be
taken using our senses alone. Let us see if we can measure
temperature with our hands.

My right hand feels warm My right hand feels
and my left hand feels cold. cold while my left
hand feels warm.
I’m confused!

How is that
possible?

Warm Cold Tap Warm Cold Tap
water water water water water water

Measuring temperature using our senses

Our sense of touch cannot be used to test the hotness and
coldness of water accurately. Hence, an instrument is needed.

Science Smart Measuring temperature

If you are taking Temperature can be measured using a thermometer. Most
temperature readings laboratory thermometers have a liquid inside the bulb — either
from a mercury mercury or alcohol. When the temperature changes, the liquid
thermometer, position level in the laboratory thermometer rises or falls.
your eye at the top of
the meniscus.

35

34

33

24 Introducing Science

This section will tell us more about the two common types Super Scientist
of laboratory thermometers — mercury and alcohol
thermometers. The Celsius scale is
named after Swedish
Mercury thermometer Alcohol thermometer astronomer, Anders
Celsius (1701–1744).
It is used to measure It is used to measure Today, the Celsius
temperatures up to 110 °C. temperatures under 70 °C . scale is commonly
used.
It cannot be used to It cannot be used to measure
measure low temperatures. high temperatures.

Its scale ranges from 0 °C Its scale ranges from –10 °C to
to 110 °C. 78 °C.

Mercury in the bulb is toxic. Alcohol in the bulb is non-toxic.

The liquid mercury is silver Alcohol is colourless, so it is
in colour. dyed red to allow readings to
be taken easily.

Differences between a mercury and an alcohol thermometer

Mercury thermometer

Alcohol thermometer Safety Precaution!
Beaf ectyaPrerefcuaul twionh!en
Do you remember the last time you visited the doctor? The handling the mercury
doctor would probably have used a thermometer to measure thermometer. Avoid
your body temperature. It is known as a clinical thermometer. contact with mercury
This thermometer has a scale of 35 °C to 42 °C. Why do you if the bulb breaks!
think this is so? Mercury is toxic and
There are two types of clinical thermometers — glass and digital. can enter the body
through the skin.

Two commonly used clinical thermometers WB Link Activity 1.10
25Introducing Science
Quick Check

1. Define temperature.
2. State the S.I. unit of temperature.
3. Compare the differences between the mercury and

alcohol thermometer.
4. Identify two clinical thermometers used.

1.7 Straight Line Graph

You should be able to:
• draw a straight line graph to show the relationship between

two factors;
• interpret data from the graph.

When we conduct an experiment, we can use many types of
graphs to present the data that we collect. Most of them are
straight lines. The purpose of a graph is to visually display
relationships, which may not be obvious from data tables.
Below is an example of a straight line graph plotted using
the information from the table shown.

Interpreting data from a graph

The aim of this experiment was to find out how mass is related
to volume. The mass of the same type of plasticine was
measured at different volumes.

Volume of plasticine (cm3) Mass of plasticine (g)
10 50
20 100
30 150
40 200

Presenting results in the table

? 250Mass of plasticine (g)

What do you get 200
when you divide the
value of the mass 150
by the value of the
volume taken at any 100
point on this graph?
You get the density 50
of this lump of
plasticine. What is its 0
value? 0 10 20 30 40 50
Volume of plasticine (cm3)

Graph of the relationship between mass and volume of plasticine

From the graph above, we can see that the mass of the
plasticine increases as the volume of the plasticine increases.

26 Introducing Science

Let us look at another example. The graph shows how the
volume of water in a measuring cylinder changes with the
number of slotted weights added to it. How can we find out
the initial volume of water in the measuring cylinder?

Volume of water (cm3) 80

70

60

50

40

30

20

10

0 5 10 15 20 25 30
0

Mass of slotted weight (g)

Graph of the relationship between the volume of

water and mass of slotted weights

By extending the line towards the y-axis (extrapolate), as
shown, the initial volume of water in the measuring cylinder
can be obtained.

Volume of water (cm3) 80 Quick Check
70
60 5 10 15 20 25 30 The volume of water
50 Mass of slotted weight (g) taken in by a plant
40 over a few hours was
30 Extrapolate the line to the y-axis plotted on a graph. What
20 can you say about the
10 experiment by looking at
the graph?
0
0 Volume (ml)
25
Other types of graphs 20

The data that we gather from experiments does not always X
form a straight line graph. The example below shows that X
some graphs can be curved.
15
10 X

Height of 30 Distance (m) 9 10 X
object (meters) 8 5X
25 7
6 0 12345
20 5 Time (hour)
4
15 3 WB Link Activity 1.11
2
10 1 27Introducing Science
0
5
1 2 3 4 5 6 7 8 9 10
0 Time (sec)
0 10 20 30 40 50
Time taken (seconds)
Graph of a ball being dropped
from a certain height

Graph of the speed of a car

1.8 Scientific
Investigations

You should be able to:
• perform scientific experiments that involve four

basic steps:
– planning the experiment,
– conducting the experiment,
– processing the data using basic science process skills

(observing, recording, measuring, communicating), and
– evaluating the experiment.
• perform a fair test i.e. changing only one variable at a
time while keeping other conditions the same during an
experiment or investigation.

A scientific investigation can be used to solve a problem or
find out new things. Scientific investigations involve the use
of the scientific method, which consists of a series of steps.

What are the steps of the scientific method?

1Ask a question. We seem to need fewer
Use your five senses to make observations. This helps you paper towels than cloth
to gather information and generate scientific questions such towels to soak up the spill.
as ‘what’, ‘when’, ‘which’, ‘where’, ‘why’ or ‘how’. I wonder why.

2 Formulate a hypothesis. I think it’s because paper
Study the information gathered and make sense of it. Then, towels absorb more water
propose a theory or hypothesis. A hypothesis is a good than cloth towels.
guess about the answer to your question.

28 Introducing Science

3Plan an experiment to test
your hypothesis.
Develop your hypothesis into an experimental aim. Decide how you
will carry out the experiment. This includes deciding what apparatus
or materials are needed, what procedure to follow, what observations
to make, what measurements to take and how to do a fair test
to prove the hypothesis. Write down your experimental plan. An
example is given below.

Aim:
To investigate if paper towels absorb more water than cloth towels

Apparatus and materials needed:
Two paper towels, two cloth towels, a beaker, water, a funnel,
a measuring cylinder, a stopwatch

Procedure:
1. Place a piece of paper towel in a beaker of water for ten seconds.
2. Take the paper towel out of the beaker.
3. Place a funnel over a measuring cylinder.
4. Squeeze all the water out of the towel into the measuring cylinder.
5. Record the amount of water collected.
6. Repeat the experiment.
7. Repeat steps 1–6 using the cloth towels.

4 Conduct the experiment. We shall make sure the size
Follow your experimental procedure. Make the experiment of the towels, the amount
a fair test by changing only one factor or variable at a time of water in the beaker and
while keeping the rest the same. Repeat your experiment the time the towel is in the
many times to ensure that the results are consistent. beaker is the same. This way,
only the type of towel will
Variables that we Variable that Variable that affect the experiment.
keep constant we change we measure
• Amount of
• Time towel is • Material of water absorbed
placed in beaker towel
• Size of towels
• Amount of water
in beaker
• Thickness of towels

Different variables in the experiment

5 Process the data from Type of Amount of water absorbed (cm3)
your experiment. towel
Use the skills of observing and Test 1 Test 2 Average
measuring to collect data. Record Paper towel
your data in a suitable format, such Cloth towel 57 53 55
as a table as shown on the right.
Then, analyse your data and conclude 32 38 37
whether your hypothesis is true.

29Introducing Science

6 Evaluate your results.
Evaluate whether your experiment was fair.
Here are some questions to ask yourself:
• Did anything go wrong in the experiment?
• What factors could have affected the results?
• What could be done to improve it?
Carry out the experiment again, if necessary.

7 Communicate your findings with others.
Share your findings with others through a final report, poster or presentation.

Summary of Scientific Investigation

Ask a question Share your
findings

Formulate a Evaluate your
hypothesis results

Science Smart Plan an Process the data
experiment from your
There are two types experiment
of data. Quantities
that we measure are Conduct your
called quantitative experiment
data. Observations
that can only be Scientists often share their findings with their peers by
described in words publishing their experimental results in scientific journals.
but not measured Their theories may be challenged or used as the basis to form
are called qualitative new theories.
data.
WB Link Activity 1.12
?
Quick Check
A fair experiment
is conducted when Draw a flow chart to show the scientific method.
only one variable
is changed in the
experiment. Discuss
with your teacher
and classmates if the
above experiment is a
fair one.

30 Introducing Science

Summary

Introducing Science

Knowledge of Accurate measurements Investigations
• Laboratory rules
• Hazard warning Scientific Method
• Ask a question
symbols • Formulate a hypothesis
• Apparatus and • Plan an experiment to test the

equipment hypothesis
• Conduct the experiment
• Process the data from the experiment
• Evaluate the experiment
• Communicate the f indings to others

Mass Time Length
• S.I. unit = kilogram • S.I. unit = second (s) • S.I. unit = metre (m)
• Instruments used: • Instruments used:
(kg) – Stopwatch – Ruler
• Instruments used: – Stop clock – Measuring tape
– Triple-beam balance – Internal and
– Electronic balance
external callipers

Density
• S.I. unit = kg/cm3

Volume • density = mass
• S.I. unit = cubic metre volume

Area (m3) Temperature
• S.I. unit = square • Instruments used: • S.I. unit = kelvin (K)
– Mathematical • Instruments used:
metre (m2) – Mercury
• Mathematical formula formulae for regular
shapes thermometer
for regular shapes – For irregular solids: – Alcohol thermometer
• Estimation with • Measuring cylinder
• Displacement can
square grids for
irregular f igures

31Introducing Science

Review Questions

1 Which one of the following instruments is used to measure the
temperature of boiling water?

A A pair of callipers
B A clinical thermometer
C An alcohol thermometer
D A laboratory mercury thermometer

2 Temperature is __________________.
A heat
B a form of energy
C a measure of a form of energy
D a measurement of the degree of hotness or coldness

3 The following graph shows that the values of two variables X and Y,
form a straight line graph when plotted. Which of the following
statements is true from the graph?

16

14

12

Value of Y 10

8

6

4

2

0 1 2 3 4 5 6
0 Value of X



A When the value of X increases, the value of Y increases.
B When the value of X increases, the value of Y decreases.
C When the value of X increases, there is no change in the

value of Y.
D There is no relation between the value of X and the value of Y.

32 Introducing Science

4 What temperature readings would you get from each of the positions
A, B and C below? Which position of your eye will give an accurate
reading of the temperature?

35 A
34 B
33 C

5 The following labels are found on the bottles of some chemicals.

P Q R S T

Which chemical:
a) can explode?
b) is poisonous?
c) catches f ire easily?
d) corrodes other substances?
e) irritates the eyes, nose and throat?

6 length length

Mahmud Af iz

a) Mahmud and Af iz are selling the same type of cloth at $5 per
arm’s length. Who would you buy the cloth from? Why?

b) What should we use to measure the cloth instead? Why?

7 You are given four instruments A, B, C and D. D
A BC

Which instrument is commonly used to measure each of the following
objects?

a) Length of a book
b) Thickness of a book
c) Height of a cupboard
d) Waist measurement of a person

33Introducing Science

8 Read the volumes shown by the following measuring cylinders.
(Remember to include the unit in your answer.)

a) cm3 b) cm3

9 Find the volume of the following irregular solids.

a) cm3 b) cm3

cm3 cm3

10 Name the apparatus/instrument(s) used for:
a) measuring the dimensions of a window,
b) measuring the volume of a liquid in a cup, and
c) f inding the density of a stone.

11 a) Which of the following objects A, B or C is the densest?

1 cm3 1 cm3 1 cm3

7.86 g 19.6 g 11.3 g

AB C

b) Which material is the densest, F, G or H?

320 g 440 g 80 g

40 cm3 40 cm3 40 cm3
Material F Material G Material H

34 Introducing Science

12 A cube of mass 40 g is lowered into a measuring cylinder containing
30 cm3 of water. The water level rises to the 38 cm3 mark.
Calculate the:

a) volume of the cube, and
b) density of the cube.
13 State the S.I. unit of temperature.
14 Write down three laboratory safety rules. Explain why these three rules

are important.
15 Name the liquids commonly found in a laboratory thermometer.
16 What is the temperature shown by each of the following

thermometers?


17 Write down some simple hypotheses for the following observations.
a) You observe a spot of light in the night sky.
b) You observe a withered plant that appears to be dying.

35Introducing Science

Chapter Classification

2 Have you seen the organism in the picture before? How do you
think scientists have classified this organism? Why do we need
to classify living organisms, and how do we classify them?

Firman Allah Subhanahu Wa Ta’ala
Tafsirnya:
Dan Allah menciptakan tiap-tiap
makhluk yang melata itu daripada air
(mani). Maka sebahagian daripada
mereka berjalan di atas perutnya
(seperti ular) dan sebahagian
daripadanya berjalan dengan dua
kaki (seperti manusia dan burung)
dan sebahagian lagi berjalan dengan
empat kaki (seperti lembu). Allah
menciptakan apa yang dikehendakiNya.
Sesungguhnya Allah Maha Berkuasa
atas tiap-tiap sesuatu.(45)

Allah has created every moving (living)
creature from water. Of them there are
some that creep on their bellies, and
some that walk on two legs, and some
that walk on four. Allah creates what
He wills. Verily Allah is Able to do all
things. (45)

(Surah an-Nur: 45)

Let’s Explore

• What is the difference between
living and non-living things?

• In what ways are organisms
classified?

• How do we construct and use a
simple classification key to identify
and classify living organisms?

36 Classification

2.1 Characteristics of
Living Things

You should be able to:
• list the main differences between living and non-living things.

There are living and non-living things in the world around us.
Living things can be differentiated from non-living things by the
characteristics below.
The characteristics of living things are:
M — Movement
R — Respiration
S — Sensitivity (responds to stimuli)
G — Growth
R — Reproduction
E — Excretion
N — Nutrition

Movement

All living things can move. Animals move from place to place
to f ind food, shelter or even to escape from their predators.
Different parts of a plant slowly move towards the direction
of light in order to make food during photosynthesis. Plants
like the Mimosa and Venus Flytrap can quickly close their leaves
when needed.

Sunlight

A cheetah runs to hunt for food. Seedlings move towards
the sunlight over time.

Respiration Oxygen Carbon
dioxide
All living things need Air
energy. They obtain energy Air forced
from food through a process drawn out
known as respiration. in
Respiration occurs all the Rib cage
time. It involves using Diaphragm
oxygen to break down
food into energy, giving off Respiration in plants Breathing in Breathing out
carbon dioxide.

37Classif ication

Constricted pupil Sensitivity (responds to stimuli)

All living things have senses that allow them to respond when
there is a change in their environment.

Dilated pupil

The pupil of the eye responds A mimosa plant closes its leaves
to bright and dim light. when it is touched.

Growth

Living things grow. Their appearance changes as they grow
from a baby to an adult.

A baby grows taller and bigger when A seed grows into an adult plant.
he becomes an adult.

Reproduction

All living things reproduce to ensure the survival of their
own kind. Some animals reproduce by giving birth and some
reproduce by laying eggs. Most plants reproduce through
seeds that grow into new plants.

38 Classif ication A bird and its chick

Excretion Try this

It is the process of removing harmful and unwanted substances A robot is able to
from organisms. move on its own, talk
All living things produce harmful or unwanted substances known and respond to the
as ‘waste’. These substances are removed through a process environment around
called excretion. Plants excrete waste (carbon dioxide) through it. Can you explain
their leaves. Animals excrete waste through their lungs (carbon why the robot cannot
dioxide), skin (sweat), kidneys (urine). be classif ied as a
living thing?
Respiration Photosynthesis
Carbon Oxygen
dioxide

Plants produce two types Humans excrete some
of waste products. During waste by sweating.
respiration, they release
carbon dioxide. When
they make food, they
release oxygen.

Nutrition

All living things need water and food to stay alive. Green plants
make their own food while animals eat plants and/or other animals.

Sunlight
Carbon
dioxide

Water

Green plants make their Living things such as Man Quick Check
own food using sunlight, depend on plants and
carbon dioxide and water. other living things for food. List the seven main
characteristics of
Non-living things do not have these seven characteristics. This is living things. Give an
the main difference between living and non-living things. example for each of
the characteristics.

39Classif ication

2.2 Diversity and
Classification of
Organisms

You should be able to:
• classify plants and animals according to common observable

characteristics;
• recognise the existence of microorganisms such as bacteria,

viruses and fungi.

The Earth supports a wide variety of living organisms. This
variety is known as diversity. Scientists have discovered
more than two million kinds of organisms so far. More are
being discovered each year, and scientists use classification
to organise this wide diversity of organisms.

Classification of organisms

Oh, I see it now! We can Can you think of other
characteristics that can
also classify them by the be used to classify these
organisms?
Hmm... You number of legs they have!

How do I classify mean like the Now you’re
all these different way they move? starting to think
animals if they look
so different? Well, if you are like scientists!
observant, you
will notice that
they do share
some common
characteristics.

Classification allows us to:
• group living organisms according to their observable
characteristics,
• identify similarities between different living organisms, and
• create an easy way to identify living organisms.
Living organisms can be broadly classified into plants, animals
and microorganisms.

40 Classification

Plants

Plants can be divided into two major groups — plants that
reproduce by seeds and plants that do not reproduce by
seeds. Plants that reproduce by seeds can be sub-divided
into flowering and non-flowering plants. The following
classif ication chart shows how plants are classif ied.

Plants

Reproduce by seeds Do not reproduce by seeds

Flowering Non-fl owering Algae Ferns
Plants plants

E.g. Hibiscus E.g. pine E.g. seaweed E.g. Bird’s Nest
Fern
• Roots, • Roots, stems • Roots, stems
stems and and leaves or leaves not • Roots,
leaves are are present present stems and
present leaves are
• Have needle- • Reproduce present
• Seeds are like leaves by spores
found in the • Reproduce
fruits • Seeds are by spores
found in the
cone

41Classif ication

Animals

Animals can be divided into two main groups — vertebrates
(with backbone) and invertebrates (without backbone).

Frog Bird
Vertebrates
Giraffe

Horseshoe crab

Octopus

Slug
Invertebrates

Science Bites

The platypus is classif ied as an egg-laying mammal. It is one of
the few species of mammals that lays eggs instead of giving
birth to their young.

42 Classif ication

Vertebrates and invertebrates can be further divided into
sub-groups as shown in the classif ication chart below.

Animals

Vertebrates Invertebrates

Arthropods Annelids Molluscs

Fish Amphibians Reptiles Birds Mammals

Vertebrates
Vertebrates are animals with backbones. They can be divided
into f ive sub-groups — fish, amphibians, reptiles, birds and
mammals.

Vertebrates

Fish Amphibians Reptiles Birds Mammals
• Cold- • Cold-blooded • Cold- • Warm- • Warm-
• Have moist blooded
blooded skin, without • Have dry blooded blooded
• Body usually scales skin usually • Have beaks • Have hair
• Breathe covered • Have feathers • Breathe
covered with through lungs with horny • Have wings
scales and moist scales through
• Breathe skin • Breathe but not all lungs
using gills • Live partly on through can f ly • Most give
• Live in fresh land and in lungs • Breathe birth to
water or sea water • Live on land through lungs their young
water • Lay eggs alive

E.g. goldfish E.g. frog E.g. chameleon E.g. chicken E.g. chimpanzee

Science Bites

Warm-blooded animals have an internal body temperature
that does not change, regardless of surrounding
temperatures. The internal body temperature of cold-blooded
animals follows the temperature of their surroundings.

43Classif ication

Invertebrates
Invertebrates are animals without backbones. They can be
further divided into three sub-groups — arthropods, annelids
and molluscs.

Arthropods
The bodies of arthropods are divided into segments (parts). They are covered with a
hard exoskeleton — a structure that gives them shape and protects them.

Insects Arachnids Myriapods
• Animals with three • Animals with four pairs • Animals with more

pairs of legs of legs than four pairs of legs

E.g. ant E.g. scorpion E.g. centipede

Annelids Molluscs

Annelids have long, Molluscs have soft
cylindrical bodies. bodies that may
Their bodies are be covered by a
divided into many shell. They use
segments. Each a muscular foot
segment may have for movement.
many bristles.
E.g. snail
E.g. earthworm

Quick Check

1. Why is classifi cation important to scientists?
2. Give an example of a f lowering plant and a

non-fl owering plant.
3. Give two examples of vertebrates and invertebrates.
4. Which group do human beings belong to? Why?

44 Classif ication

Microorganisms

Microorganisms are very small living organisms that can only be
seen under a microscope. Microorganisms are found everywhere.
They are neither plants nor animals. There are three types of
microorganisms — bacteria, viruses and fungi.

Bacteria
They are:
• visible under the microscope, and
• larger than viruses.
Bacteria may be both useful and harmful. They are useful as they are involved in the
breakdown of dead plants and animals. Bacteria are used to curdle milk in the process of
making cheese and yoghurt. However, they can be harmful as they can cause diseases
in living plants and animals.

Viruses E.g. Escherichia coli bacteria

Fungi

• Fungi have no
roots, stems or
leaves.
• Some fungi feed
on dead matter.
Others feed on
living plants and
E.g. mould

E.g. H1N1 Influenza A virus animals.
• Some fungi
They are: can be useful.
• the smallest disease-causing An example
is Penicillium
organisms known. notatum that
• not visible under the ordinary light produces the
antibiotic,
microscope. To examine their detailed penicillin.
structure, an electron microscope • Others can
is required. cause fungal
• able to cause diseases like AIDS,
H1N1, Influenza and Hepatitis.

diseases such as
E.g. ringworm infection ringworm.

45Classification

2.3 Classification Key

You should be able to:
• construct a classif ication key;
• use a classifi cation key to identify living organisms.

A classification key shows how organisms are grouped
according to their common characteristics.
It allows us to look up information easily and can be used
to identify individual organisms or groups of organisms. To
make a classif ication key, we need to identify similarities and
differences between organisms. The following is an example
of how students in a class can be classif ied.

S te p 1 Identify one main difference S tep 2 Within the two main groups,

to divide the group into two. identify another difference that can
divide each group into two.

S tep 3 Continue to identify differences S te p 4 Draw up the key according to

that can split each small sub-group your classif ication.
into two, until every group is left
with one member.

46 Classif ication

You can present a classif ication key in the form of a chart like
quick references.

Pupils in

Male

Double eyelids Single eyelids

Short- Normal Short- Normal
sighted eye sight sighted eye sight

Ramli Gopi Bala Wei Hao

Guo Xiang Jun Yang Ahmad Firuz

Classifying the pupils in a cla

With the above classif ication key, you know that the names o
Fatima and Nora. Can you state the names of the boys who ha

47Classif ication Quick Check

1. How does a classif ication key help in classifying and identify

2. Construct a classif ication key to classify the following anima

• Ostrich • Chimpanzee
• Fish • Frog
• Snake

e this. Presenting the key in such a way is useful for making

n a class

Female

Double eyelids Single eyelids

Short- Normal Short- Normal
sighted eye sight sighted eye sight

Fatima Aminah Yulin Xin Hui

Nora Mei Qing Uma Rowati

ass using a classification key

of the girls who have double eyelids and are short-sighted are
ave single eyelids and are short-sighted?

ying organisms? WB Link Activity 2.1
als:

Summary Classifi cation

provides a meaningful
and systematic way
to study

Diversity

M — Movement Living Non-living
R — Respiration things things
S — Sensitivity (responds to stimuli) can be
G — Growth classif ied Identif ied and
R — Reproduction into classif ied using a
E — Excretion classif ication key
N — Nutrition

Plants Animals Microorganisms

With seeds Without seeds Bacteria
Viruses
Flowering Non- Algae Ferns Fungi
plants f lowering Vertebrates
plants

Invertebrates

Fish Arthropods
Amphibians Annelids
Molluscs
Reptiles
Birds

Mammals

48 Classif ication

Review Questions

1 Which of these is not a characteristic of living things?
A Moving
B Feeding
C Growing
D Keeping warm

2 Which of these characteristics of living things is responsible for releasing
energy from food?

A Nutrition
B Excretion
C Respiration
D Reproduction

3 Which of the following is a common feature of a sparrow and a dolphin?
A They lay eggs.
B They have moist skin.
C They are warm-blooded.
D They do not have hands and legs.

4 Fatimah has a doll at home that can move and respond to stimuli.
a) Explain why the doll is not alive even though it can move and

respond to stimuli.
b) Explain how a plant moves and responds to stimuli.

5 Classify the organisms below as vertebrates and invertebrates.
a) Cat
b) Duck
c) Mosquito
d) Caterpillar

6 List two characteristics for each of the following vertebrates:
a) Reptiles
b) Mammals
c) Amphibians

49Classif ication