Science (Workbook) Y7

Observations

1. Label the diagram below to show the distillation process.



stopper
water out

heat boiling
chips

water in

2. What was the temperature at which the first drops of distillate were
collected in the beaker?

Temperature 

Discussions

1. After distilling for ten minutes:
a) Describe the appearance of the distillate collected in the beaker.

b) What is the difference between the distillate and the original liquid?

c) What happened to the temperature as the distillate was collected?

2. Identify the distillate collected.

3. What is the function of the condenser?


Water 39

Chapter 4 Activity 4.5
Water
Paper Chromatography
Aim

• To separate a mixture of coloured dyes through the process of
paper chromatography

Apparatus

• Boiling tube
• Test tube rack

Materials

• Alcohol
• A wooden splint
• Coloured food dye/ink
• Split cork (to fit the mouth of the boiling tube)
• Chromatography paper (cut to the same length as the boiling tube)

Procedure

1. Use a pencil to draw a line 3 cm from one end of the chromatography
paper. This is the baseline.

baseline
3 cm

2. Dip the wooden splint into the coloured dye or ink, and make a small
mark on the baseline.

spot of dye

3. Pour about 2 cm in depth of alcohol into the boiling tube. Insert the split cork
chromatography paper into the split cork and lower the paper into
the boiling tube. Make sure the baseline is just above the level of the
alcohol.

level of alcohol

40 Water

4. Remove the chromatography paper when the alcohol nearly reaches the split cork
top and leave to dry.

solvent front

Observations

1. Examine the dry chromatogram. How many colours do you see?

2. State the colours separated from the coloured dye or ink.


Paste your
chromatogram here.

Water 41

Chapter 4 Activity 4.6
Water
Water Conservation
Aim

• To find ways of conserving water at home

Task

• Design a poster to educate the public on ways to save water.
• Use the space below to sketch your ideas for the poster.

42 Water

Chapter 5 Activity 5.1
Cell Structure and Organisation
Microscope
Aims

• To recognise the functions of the different parts of a microscope
• To learn how to use a microscope

Apparatus

• Microscope
• 4 Cover-slips
• 4 Glass slides
• Mounted needle

Materials

• A pair of scissors
• Four specimens (e.g. fibre, dust, hair, pond water)

Part A Parts of a Microscope and Their Functions
Procedure

1. The main parts of a microscope are shown below.

eye piece

arm large knob
stage tube

objective lens
clips
mirror

2. Explore the uses and functions of the different parts of the microscope.

43Cell Structure and Organisation

Part B Observing an Image Through the Microscope

Background Information
Observe the following rules when using a microscope:
• Always carry the microscope with both hands.

Hold the arm of the microscope with one hand
and place the other hand under its base.
• Always keep the microscope and its lenses dry and clean.
1. Look for small specimens, such as dust, fibre and hair, and place one
sample on a glass slide.

2. Using a mounted needle, gently lower the cover-slip onto the specimen.


3. Make sure that there are no air bubbles trapped within the coverslip.
Keep the bottom of the slide dry.

44 Cell Structure and Organisation

4. Place the microscope on the laboratory table near a window or
light source.

5. Look through the eye piece. Move the mirror to get bright light.
6. Use the shortest objective lens.

7. Place the prepared glass slide on the stage, directly below the objective
lens. Make sure the slide is held firmly by the stage clips.

45Cell Structure and Organisation

8. Look through the eye piece. Use the large knob and small knob to focus.

Observations

Draw the specimens as seen through the microscope in the spaces below.
Label each of them.

46 Cell Structure and Organisation

Chapter 5 Activity 5.2
Cell Structure and Organisation
Examining Animal Cells
Aim

• To identify the different parts of an animal cell

Apparatus

• Cover-slip
• Glass slide
• Microscope
• Mounted needle

Materials

• Tissue paper
• A blunt end toothpick
• Diluted iodine solution/methylene blue solution

Procedure

1. Use the blunt end of a clean toothpick to gently scrape the inside of
your cheek.

Do not share the same toothpick
with your friend. Throw it away after
using it.

2. Place the cheek scrapings on a glass slide. Add a drop of iodine or
methylene blue solution to the specimen. Spread out the cells.

Note: Iodine or methylene blue solution
is used to stain specimens.

3. Carefully lower a cover-slip over the cheek scrapings on the slide using
a mounted needle as shown below. The iodine will spread out beneath
the cover-slip. Make sure that there are no air bubbles trapped beneath
the cover-slip. Absorb the excess iodine solution with a piece of tissue
paper.

4. Examine the cheek scrapings under a microscope. Locate the cheek 47
cells with the shortest objective lens (e.g. 10×). Examine the cheek
cells again with a longer objective lens (e.g. 40×).

Cell Structure and Organisation

Observations

1. Examine the cheek cells under the microscope and draw one cheek cell
in the space provided below. Label clearly the cell membrane, cytoplasm
and nucleus of the cell.

2. What part of the cheek cell is not visible under the ordinary microscope
that you have used? Give one reason why it is not visible.




48 Cell Structure and Organisation

Chapter 5
Cell Structure and Organisation

Activity 5.3

Examining Plant Cells

Aim

• To identify the different parts of a plant cell

Apparatus

• Scalpel
• Cover-slip
• Glass slide
• Microscope
• Mounted needle
• A pair of forceps

Materials

• Fleshy scale leaf from an onion bulb
• Dilute iodine solution/methylene blue solution

Procedure

1. Take a fleshy scale leaf from an onion bulb.

scale leaf

onion bulb

2. Bend the leaf to break it.

3. Using a pair of forceps, gently peel off the epidermis (skin) from the
inner surface of the leaf.



4. Use the scalpel to cut off a small piece of the epidermis. Place the piece
of epidermis on a glass slide.

49Cell Structure and Organisation

5. Add a drop of dilute iodine or methylene blue solution and place a
cover-slip over the epidermis.

6. Examine the epidermis under a microscope.

Observation

Draw and label the magnified view of an onion cell.

50 Cell Structure and Organisation

Chapter 5 Activity 5.4
Cell Structure and Organisation
Digestive System
Aim

• To recognise the different organs in the digestive system

Materials

• Glue
• A pair of scissors

Procedure

1. Use the cut-out sheet in Appendix 5A.

2. Cut out the different organs in the digestive system and correctly place
them to complete the digestive system model on the next page.

51Cell Structure and Organisation

52 Cell Structure and Organisation

Appendix 5A

liver

gall bladder

stomach

mouth
small
intestine
large
intestine

pancreas rectum and anus salivary glands

53Cell Structure and Organisation



Chapter 6 Activity 6.1
Force and Pressure
Observing the Effects of Friction on Motion
Aims

• To observe the effects of friction on motion
• To investigate the effect of a lubricant (oil) on friction

Materials

• A coin
• An eraser
• A half-metre rule
• Small amount of oil
• A small rectangular wooden block

Procedure

1. Put a coin, a small rectangular wooden block, and an eraser on a
half-metre rule as shown in the diagram below.



eraser

wooden block half-metre rule
coin h

20¢

2. Gently raise the end closest to the eraser, tapping the ruler lightly as you
do so.

3. Measure and record the height, h, at which each object starts moving.
(h is the height from the top of the ruler to the table surface.)

4. Remove the objects from the ruler and spread a thin layer of cooking oil
on the underside of each object.

5. Repeat the experiment, measuring h for each object.

55Force and Pressure

Observation h without oil (cm) h with oil (cm)

Object
Coin
Wooden block
Eraser

Discussion

1. a) Which object moved first?

b) Why did the object in (a) move first?


2. What effect did the oil have on friction?



Conclusion

1. State how friction affects the motion of an object.


2. State the effect of using a lubricant.



56 Force and Pressure

Chapter 6 Activity 6.2
Force and Pressure
Investigating the Effects of Forces
Aims

• To verify the effect of a force on:
a) the size of a body,
b) the shape of a body, and
c) the speed of a body

Materials

• Wire cutter
• A round pencil
• 1 m of thick copper or steel wire

Part A Investigating Forces

Procedure

1. Fasten one end of the wire to the pencil.

2. Hold the wire firmly with one hand and twist the pencil with the other
hand. Make sure the coils are twisted close to each other. Make 20 turns
around the pencil.

3. Loosen the coil of wire and remove it from the pencil.
4. Cut the straight ends of the wire with a wire cutter.
5. You have just made a spring. Stretch the spring with your hands as

shown in the diagram below. Observe what happens to the spring.

6. Compress the spring with the palms of your hands as shown in the
diagram below. Observe what happens to the spring.

57Force and Pressure

Observation . of the spring.
the of the spring.
1. When the spring is stretched:
It becomes .
The force that you applied the

2. When the spring is compressed:
It becomes
The force that you applied

Part B Identifying the Effects of Forces

Describe the effect of the force in each of the situations below.

1. Shamsul kicked the football into the goal.



The force that he applied changed the
of the football.

2. Yacob is pedalling faster to get home on time.

The force that he applied changed the
of the bicycle.

58 Force and Pressure

3. Nurul rolled out a round ball of dough flat.

The force that she applied changed the
of the dough.

4. Mr Hamid screeched to a complete stop when the traffic light
turned red.

The force that he applied changed the
of the car.

5. Karim stretched and released the elastic band of the catapult.

The force that he applied changed the
of the elastic band.

59Force and Pressure

Chapter 6
Force and Pressure

Activity 6.3

Investigating the Effects of Forces on a Spring Balance

Aim

• To measure the extension of a spring

Apparatus

• Retort stand with clamp

Materials

• Ruler
• A spring
• 50 g and 100 g slotted masses

Procedure

1. Hang the spring from a retort stand as shown in the diagram below.

2. Measure the initial length of the spring.

Initial length of
the spring

3. Attach a 100 g mass to the spring.
4. Measure the new length of the spring.
5. Calculate the extension of the spring, which is:
Extension of the spring  new length of the spring  initial length of the spring

60 Force and Pressure

New length
of spring

6. Repeat steps 3 to 5 with different masses and record your values in the
table below.

Observation

Initial length 
Extension of the spring when different masses are attached to it.

Total mass (g) New length of the Extension of
spring (cm) spring (cm)
100
150
200
250
300

61Force and Pressure

Discussion Extension/cm

Plot a graph of total mass against extension. .

Total mass/g

300

250

200

150

100

50

0

Conclusion

As we increase the load, the extension of the spring will

62 Force and Pressure

Chapter 6
Force and Pressure

Activity 6.4

Investigating Pressure

Aim

• To investigate the pressure exerted by different types of footwear

Materials • A pair of rubber flip-flops
• Three pieces of graph paper
• A pencil • A pair of stiletto-heeled shoes
• Bathroom scales
• A pair of school shoes

Procedure

1. Stand on the bathroom scales. Record your mass.

2. Place a rubber flip-flop on a piece of graph paper.

3. Trace the outline of the sole of the rubber flip-flop.

4. Find the area of the outline you drew using the graph paper.

5. Multiply each value by two to obtain the total area of contact with the
ground. Record your findings in the table below. The pressure exerted
on the ground may be calculated by dividing your weight by the area of
contact with the ground.

6. Repeat steps 2 to 5 with a school shoe and stiletto-heeled shoe.

63Force and Pressure

Observation kg

Mass 

Weight  Mass (kg) × 10 (N/kg)

 (kg) × 10 (N/kg)

N

Area of contact with the ground and pressure exerted while wearing
different footwear.

Type of Area of contact with Pressure exerted on the
footwear the ground (cm2) ground while wearing
footwear (N/cm2)

Flip-flops

School shoes

Stiletto-heeled
shoes

Discussion

Which type of footwear exerts the most pressure on the ground when worn?

Conclusion

From the results of your experiment, which type of footwear would you
wear to take a walk on the beach? Why?

64 Force and Pressure

Chapter 7 Activity 7.1
Energy
Forms of Energy
Aim

• To learn about the forms of energy we use in daily life

Procedure

1. Look at the following pictures. Identify the forms of energy:

a. when a ball rolls on the b. before a book drops off the
ground. table.

energy energy
c. a chicken drumstick.
d. a battery.

energy energy

Energy 65

e. a beaker of boiling water. f. when a person plays a violin.

energy energy
g. when a candle burns.
h. when a baby hammock
hangs from a ceiling.

energy energy

66 Energy

Chapter 7 Activity 7.2
Energy
Energy Transformation
Aim

• To investigate the different types of energy changes

Apparatus

• Magnifying glass

Materials • A pair of tongs
• A wind-up toy car
• A candle • A piece of dark-coloured paper
• An ice cube
• A matchbox

Procedure

Part A Magnifying Glass

1. Hold the magnifying glass in the path of the sun’s rays, directing them
onto a piece of dark-coloured paper.

2. Adjust the distance of the paper so that a spot of light is seen on the
paper. Hold it in position for a few minutes.

2. What happened to the paper? This experiment can
hurt the eyes. Put on
3. What energy changes have taken place? dark glasses to do
this experiment.

Energy 67

Part B Toy Car

1. Wind up the toy car.

2. What type of energy is used to wind up the toy car?

3. Now, release the toy car. What do you observe?

4. What energy changes have taken place?


Part C Burning Candle

1. Using a match, light a candle.
2. What energy changes have taken place in the candle?

3. Bring an ice cube close to the candle flame.

4. What happened to the ice cube?

5. What type of energy caused the changes observed?


68 Energy

Chapter 7
Energy

Activity 7.3

Principle of Conservation of Energy
(Teacher’s Demonstration)

Aim

• To investigate the energy transformation of a pendulum

Apparatus • A retort stand and clamp
• A piece of string
• A pendulum bob

Materials

• Two ruler
• A block of wood

Procedure

1. Hang a pendulum bob from a retort stand.

2. Position the pendulum bob at its lowest point such that it just touches
the block of wood. The pendulum bob should not be in contact with the
table surface.

3. Pull the pendulum bob to one side to a height, h (measured by a
ruler held vertically). Release it such that it will move the block by a
distance, s.

ruler

A bob block s
h

4. Use another ruler to measure the distance, s.
5. Repeat steps 3 and 4 for a range of values of h.
6. Record your readings.

Energy 69

Discussion

1. Record your readings in the table below.

Height of pendulum bob Distance moved by
above its lowest point, h (cm) wooden block, s (cm)

2. State the energy the pendulum bob has at point A.

3. As the pendulum bob is pulled back higher, the amount of energy it has
(decreases/increases).
4. What happens to the wooden block when it is hit by the pendulum bob?

5. What energy conversion takes place when the pendulum bob hits the

block?

6. The wooden block moves further when the pendulum bob is pulled back
(higher/lower).

70 Energy

Chapter 7
Energy

Activity 7.4

Fruit Battery (Teacher’s Demonstration)

Aim

• To set up a battery made up of a lemon

Apparatus

• LED light or light bulb with holder
• 3 connecting wires with crocodile clips at the ends

Materials • A fruit knife
• Copper plates
• A lemon
• Plastic cup

Procedure

1. Roll the lemon around the table, gently pressing it to soften the lemon
up. This is to get the juices flowing inside the fruit without breaking its
skin.

2. Cut the lemon into half.

3. Insert two copper plates into the lemon so that half of each plate is
sticking out. The plates should be 2 cm apart.

4. Place the lemon on a plastic cup for support. Connect each plate with
the crocodile clips and wires to a galvanometer. Do not get the clips wet.

Observations

1. What did you observe when the crocodile clips were connected to the
LED lights?



2. State the energy changes that took place.



Energy 71

Chapter 7 Activity 7.5
Energy
Conserving Energy
Aims

• To find ways of conserving energy

Task

Design a poster to educate the public on how they can conserve energy
at home.

72 Energy

Chapter 8 Activity 8.1
Magnetism
Magnetic Force
Aim

• To observe the effects of magnets

Apparatus

• Spring balance
• Two strong bar magnets

Procedure

1. Place a magnet on the balance as shown in the diagram below. Record
the reading of the balance (Initial reading).

N

S

2. Hold another magnet above the first magnet as shown in the diagram
below. Record the reading of the balance (Reading 1).



S
N
N
S

3. Now, hold the magnet with its South pole pointing down above the first
magnet. Move it as near as possible without the two magnets meeting
one another. Record the reading of the balance (Reading 2).

Magnetism 73

Observation

Record the readings that you have obtained below. Remember to indicate
the units.
Initial reading 
Reading 1 
Reading 2 

Discussion

1. Compare Reading 1 and Reading 2. Which of them is higher?

2. The reading is higher because there is a force acting on the first magnet.

Is this force attractive or repulsive?


74 Magnetism

Chapter 8 Activity 8.2
Magnetism
Investigating Magnets
Aim

• To investigate a property of magnets

Apparatus

• Non-magnetic retort stand

Materials

• String
• Magnet
• Iron rod
• Compass

Procedure

1. Set up the apparatus as shown in the following diagram.

2. Allow the magnet to come to rest.

3. Repeat step 2 three times. Repeat the experiment,
replacing the magnet with the iron rod.

Discussion

1. In which direction did the magnet come to a rest?

2. Does the iron rod always come to a rest in the same direction?

3. What conclusion can you make about the magnet from this experiment?


Magnetism 75

Chapter 8
Magnetism

Activity 8.3

Magnetic and Non-magnetic Materials

Aim

• To distinguish between magnetic materials and non-magnetic materials

Materials • Bar magnets
• One cent coin
• Eraser • Aluminium foil
• Iron nails • A piece of cloth
• Iron filings • Steel paper clips
• Plastic ruler
• Copper wire

Procedure

1. Place a magnet near each object in turn. Record your observations and classify
the object as a magnetic or a non-magnetic material in the table below.

Object Observations Magnetic /
Non-magnetic material
Eraser
Iron nails
Iron filings
Plastic ruler
Copper wire
One cent coin
Aluminium foil
A piece of cloth
Steel paper clips

Discussion

1. From your observations, which objects are made of magnetic materials?

2. Not all metals are magnetic materials. Can you name three such metals?


76 Magnetism

Chapter 8
Magnetism

Activity 8.4

Drawing Magnetic Fields

Aim

• To use iron filings to show the presence of magnetic fields around magnets

Materials • Two bar magnets
• Transparent plastic sheet
• Plasticine
• Rectangular box
• Some iron filings

Part A A Single Magnet

Procedure

1. Place a bar magnet in the centre of a box.

2. Raise it to the same height of the box by adding some plasticine
beneath it.

N

plasticine

s

3. Lay a plastic transparent sheet over the bar magnet and support it so
that it is in a horizontal position.

4. Sprinkle some iron filings on the transparent sheet over the bar magnet.
Do this a little at a time.

5. Scatter the filings evenly and tap the transparent sheet to make the
lines appear.

6. Draw the pattern that you see in the space provided on page 78. Magnetism 77

Observation

NS

78 Magnetism

Part B Two Magnets with Unlike Poles Facing Each Other
Procedure

1. Place two bar magnets in the centre of a box. The North pole of one bar
magnet should be facing the South pole of the other.

2. Raise them to the same height of the box by adding some plasticine
beneath them.

N

s

N

s

3. Lay a plastic transparent sheet over the bar magnets and support it so
that it is in a horizontal position.

4. Sprinkle some iron filings on the transparent sheet over both bar
magnets. Do this a little at a time.

5. Scatter the filings evenly and tap the transparent sheet to make the
lines appear.

6. Draw the pattern that you see in the space provided on page 80.

Magnetism 79

Observation

N SN S

80 Magnetism

Part C Two Magnets with Like Poles Facing Each Other
Procedure

1. Place two bar magnets in the centre of a box. The North pole of one bar
magnet should be facing the North pole of the other.

2. Raise them to the same height of the box by adding some plasticine
beneath them.
s

N
N

s
3. Lay a plastic transparent sheet over the bar magnets and support it so

that it is in a horizontal position.

4. Sprinkle some iron filings on the transparent sheet over both bar
magnets. Do this a little at a time.

5. Scatter the filings evenly and tap the paper to make the lines appear.
6. Draw the pattern that you see in the space provided on page 82.

Magnetism 81

Observation

S NN S

82 Magnetism

Notes

94 Postlim

Notes

Postlim 95

Notes

96 Postlim