Science questions, unit 6

Nama / NameKelas / ClassTarikh / Date

Heat

42 marks. Use Practice to check each answer as you go, or Exam to answer everything first. Ask a grown-up to help you mark the written answers.

Section A: objective questions

12 marks

Choose the best answer for each question.

Question 1

Heat is a form of ______ that is transferred because of a difference in temperature.

force
energy
matter
light

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Heat is a form of energy. It is transferred when there is a difference in temperature.

For the teacher: Remembering, low difficulty, standard 6.1.1

Textbook p. 146

Question 2

What is the standard unit for measuring temperature?

Gram (g)
Centimetre (cm)
Second (s)
Degree Celsius (°C)

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Temperature is measured in degree Celsius, with the symbol °C, using a thermometer.

For the teacher: Remembering, low difficulty, standard 6.1.1

Textbook p. 146

Question 3

Which statement describes temperature?

The degree of hotness or coldness of a material
The energy that moves from a cold place to a hot place
The amount of water in a material
The size of a material

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Temperature is the degree of hotness or coldness of a material. Heat is the energy that is transferred.

For the teacher: Understanding, low difficulty, standard 6.1.1

Textbook p. 146

Question 4

What is the normal body temperature of a healthy person?

0 °C
27 °C
37 °C
100 °C

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Normal body temperature is 37 °C. Water freezes at 0 °C and boils at 100 °C.

For the teacher: Remembering, low difficulty, standard 6.1.1

Textbook p. 146

Question 5

Diagram 1 shows the liquid level in a thermometer when the temperature of the surroundings decreases (left) and increases (right). Why does the liquid level rise when the temperature increases?

Two thermometers in beakers: the liquid level at 30 degrees when the temperature decreases and at 40 degrees when it increases — Diagram 1

The liquid contracts
The liquid expands
The glass tube melts
The liquid evaporates completely

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The liquid gains heat and expands, so its level rises. When it loses heat it contracts and the level falls.

For the teacher: Understanding, low difficulty, standard 6.1.2

Textbook p. 147

Question 6

Siti measures the temperature of water in a beaker. Which is the correct way to use the thermometer?

Stir the water with the thermometer
Let the bulb of the thermometer touch the bottom of the beaker
Take the reading as soon as the thermometer is put in the water
Wait until the liquid level is constant, then read with the eye level with the meniscus

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The bulb must not touch the bottom of the beaker, the thermometer must not be used for stirring, and the reading is taken when the liquid level is constant.

For the teacher: Applying, low difficulty, standard 6.1.2

Textbook p. 147

Question 7

What is the meniscus level in a thermometer?

The curved level of the liquid in the glass tube
The round bulb at the bottom of the thermometer
The temperature scale beside the glass tube
The top end of the glass tube

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The meniscus level is the curved level of the liquid in the glass tube of a thermometer. The eye must be level with it when the temperature is read.

For the teacher: Understanding, low difficulty, standard 6.1.2

Textbook p. 148

Question 8

What is the freezing point of water?

100 °C
37 °C
0 °C
26 °C

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The freezing point of water is 0 °C. The boiling point is 100 °C.

For the teacher: Remembering, low difficulty, standard 6.1.3

Textbook p. 150

Question 9

Diagram 3 shows the temperature of ice that is heated until the water boils. At which minute does the water first reach its boiling point?

Line graph of temperature against time: 0, 18, 42, 66, 90, 100 and 100 degrees at 0, 5, 10, 15, 20, 25 and 30 minutes — Diagram 3

5 minutes
10 minutes
20 minutes
25 minutes

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The temperature reaches 100 °C, the boiling point of water, at 25 minutes. After that it stays at 100 °C.

For the teacher: Applying, low difficulty, standard 6.1.3

Textbook p. 151

Question 10

Diagram 4 shows the temperature of a beaker of hot water left in a room. What is the room temperature?

Line graph: the temperature falls from 90 degrees and stays at 30 degrees from 25 minutes — Diagram 4

90 °C
40 °C
30 °C
0 °C

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Hot water loses heat until its temperature equals the room temperature, then it stays constant. The line is constant at 30 °C.

For the teacher: Analysing, low difficulty, standard 6.1.4

Textbook p. 152

Question 11

A metal ball passes through a ring easily. After it is heated for three minutes, it cannot pass through the ring. What is the reason?

The ball expanded when it gained heat
The ball contracted when it gained heat
The ring contracted when it lost heat
The ball became heavier

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The ball gained heat from the Bunsen burner and expanded, so it became too big for the ring.

For the teacher: Understanding, medium difficulty, standard 6.1.5

Textbook p. 155

Question 12

Why are electric cables hung loosely between the electric poles?

Electric cables hung between tall electric poles — Diagram 5

To make the cables look nice
To let the cables contract when the temperature decreases
To let the cables expand when the temperature decreases
To save electricity

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Cables contract when they lose heat. If they were tight they could snap, so they are hung loosely.

For the teacher: Applying, medium difficulty, standard 6.1.6

Textbook p. 158

Section B: structured questions

30 marks

Answer all questions. Circle the answer or write it in the space.

Question 13

Ana is drinking a hot drink. After a while the drink becomes cold.

[2 marks] (a)What is the meaning of heat?

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A form of energy [1 mark]1
that is transferred because of a difference in temperature [1 mark]1

Tick each point you got.

[1 mark] (b)What is the meaning of temperature?

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The degree of hotness or coldness of a material1

Tick each point you got.

[1 mark] (c)The drink became cold because it ______ heat to the surroundings.

AgainedBlost

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lost

A material becomes colder when it loses heat.

For the teacher: Remembering, low difficulty, standard 6.1.1

Textbook p. 146

Question 14

Hasnah measures the temperature of three samples of water: cold water, tap water and hot water. Diagram 6 shows the thermometers P, Q and R.

Three thermometers: P at 58, Q at 14 and R at 26 degrees Celsius — Diagram 6

[1 mark] (a)What is the reading of thermometer P?

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58 °C (unit needed)1

Tick each point you got.

[1 mark] (b)What is the reading of thermometer Q?

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14 °C (unit needed)1

Tick each point you got.

[1 mark] (c)The tap water is at 26 °C. Which thermometer shows the tap water?

APBQCR

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R shows 26 °C.

[1 mark] (d)How many degrees hotter is P than Q?

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44 °C (58 − 14 = 44)1

Tick each point you got.

For the teacher: Applying, low difficulty, standard 6.1.2

Textbook p. 149

Question 15

Diagram 7 shows the story of Mr Thermometer. The thermometer is put in ice, then in water that has warmed to room temperature, and then in water that is heated until it boils.

Mr Thermometer story: ice at 0 degrees, water at 26 degrees after 40 minutes, then heated water boiling at 100 degrees after 15 minutes — Diagram 7

[1 mark] (a)What is the temperature of the water after 40 minutes, when it has warmed up?

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26 °C (unit needed)1

Tick each point you got.

[1 mark] (b)By how many degrees does the temperature rise from the warm water to the boiling water?

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74 °C (100 − 26 = 74)1

Tick each point you got.

[1 mark] (c)State the relationship between the heating time and the temperature of the water.

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The longer the heating time, the higher the temperature of the water / as the heating time increases, the temperature increases1

Tick each point you got.

For the teacher: Understanding, low difficulty, standard 6.1.3

Textbook p. 150

Question 16

Diagram 8 shows the temperature of water that is heated and the temperature of water that is cooled.

Line graph: heated water rises from 30 to 100 degrees by 20 minutes; cooled water falls from 100 to 40 degrees; the lines cross at 10 minutes at 70 degrees — Diagram 8

[1 mark] (a)What is the trend of change of the temperature as the water is cooled?

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The temperature decreases (goes down)1

Tick each point you got.

[1 mark] (b)What is the boiling point of the water in the graph?

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100 °C1

Tick each point you got.

[1 mark] (c)At which minute does the heated water reach its boiling point?

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20 minutes1

Tick each point you got.

[2 marks] (d)At which minute is the temperature of the heated water the same as the cooled water? What is that temperature?

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10 minutes [1 mark]1
70 °C [1 mark]1

Tick each point you got.

[1 mark] (e)What hypothesis can you make from the trend of the heated water?

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The longer water is heated, the higher its temperature (until it boils)1

Tick each point you got.

For the teacher: Analysing, medium difficulty, standard 6.1.3

Textbook p. 162

Question 17

Diagram 9 shows a boy with a cup of hot tea. He stirs it with a metal spoon and the spoon becomes hot.

Comic: a boy pours hot tea, stirs it with a metal spoon, finds the spoon hot, and drinks the tea when it is less hot — Diagram 9

[2 marks] (a)Why does the metal spoon become hot?

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Heat flows from the hot tea to the spoon [1 mark]1
The spoon gains heat [1 mark]1

Tick each point you got.

[1 mark] (b)The tea is left in the room for a long time. What will the temperature of the tea become?

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It becomes equal to the room temperature (and then stays constant)1

Tick each point you got.

For the teacher: Understanding, low difficulty, standard 6.1.4

Textbook p. 152

Question 18

Melia pours hot water into a bottle and screws on the cap, as in Diagram 10. Later the cap pops off. In Diagram 11, ice cubes are put into the top glass of two stuck glasses and they come apart.

Hot water poured into a bottle with a cap that pops off — Diagram 10

Two stuck glasses, ice cubes put in the top glass, and the glasses separated — Diagram 10

[2 marks] (a)Why does the bottle cap pop off in Diagram 10?

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The air in the bottle gained heat from the hot water [1 mark]1
The air expanded [1 mark]1

Tick each point you got.

[2 marks] (b)Why can the glasses be separated in Diagram 11?

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The glass lost heat to the ice cubes [1 mark]1
The glass contracted [1 mark]1

Tick each point you got.

For the teacher: Applying, medium difficulty, standard 6.1.5

Textbook p. 154

Question 19

Diagram 12 shows a railway track with a gap between the connectors. Aiman says, "The workers made a mistake. They should fill the gaps with metal so that the track is one long piece."

Close-up of a railway track showing a small gap between the ends of two rails — Diagram 12

[1 mark] (a)Is Aiman correct?

AYesBNo

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The gaps are made on purpose.

[2 marks] (b)Explain why the gaps are left between the connectors.

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The track expands when the temperature of the surroundings increases [1 mark]1
The gaps allow it to expand, so the track does not bend [1 mark]1

Tick each point you got.

For the teacher: Evaluating, high difficulty, standard 6.1.6

Textbook p. 158

Question 20

Hakim makes a handmade thermometer. He fills a plastic bottle with coloured water and fits a drinking straw through the cap, so that the water rises into the straw. He puts the bottle into a glass container of hot water and then into a glass container of ice.

[1 mark] (a)Predict what happens to the level of the coloured water in the straw when the bottle is in the hot water.

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The level rises (the water expands)1

Tick each point you got.

[2 marks] (b)Predict what happens to the level when the bottle is in the ice. Give a reason.

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The level falls [1 mark]1
The water loses heat and contracts [1 mark]1

Tick each point you got.

For the teacher: Creating, high difficulty, standard 6.1.5

Textbook p. 160

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