chapter 7 heat

Form 1 ScienceChapter 7

FORM 1 CHAPTER 7HEAT

1. Diagram 1.1 shows the physical changes in the state of water.

(a) Name processes X and Y in Diagram 1.1 using the following words

[2 marks]

(b) Diagram 1.2 shows the drying of clothes under the sun.

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Melting Boiling Condensation

Diagram 1.2

Y : …………………..…..

Ice

Steam

Process Z

X : …………………..…..

Diagram 1.1


(i) Name the physical process shown in Diagram 2.1.

……………………………………………………………………………………………………

[1 mark]

(ii) Draw the changes in the arrangement of particles during this process.

[2 marks]

(iii) State whether heat is absorbed or released during this process.

…………………………………………………………………………………………………….

[1 mark]

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2. Diagram 2.1 shows an activity involving different ways of heat flow from a fire.

(a) State the ways of heat flow in Diagram 2.1 using the following information.

[2 marks]

(b) Draw the direction of heat flow from the hot pot to the hand in the box provided in Diagram 2.2

[1 mark]

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Radiation Convection Conduction

Diagram 2.2

Y : …………………………….

Diagram 2.1

Z : …………………………

X : ………………………………


(c) Diagram 2.3 shows an electric kettle that functions using the principle of heat transfer.

(i) State the function of X.

……….………………………………………………………………………………………….

[1 mark]

(ii) Draw arrows to show the convection current that occur in the kettle in the box in Diagram 2.3.

[1 mark]

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X

Diagram 2.3


3. Diagram 3.1 shows an activity that is carried out to study the effect of heating on a metal ball.

(a) What can be observed when the heated metal ball is placed on the ring? …………………………………………………………………………………………………

[1 mark]

(b) What is the effect of heat on the metal ball?

………………………………………………………………………………………………………….

[1 mark]

(c) What happens to the particles in the metal ball when the metal ball is heated? ………………………………………………………………………………………

. ………

[1 mark]

(d) Draw the changes in arrangement of particles when the metal ball is heated.

[1 mark]

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metal ball

ring

metal ball

ring

Before Heating After Heating

Diagram 3.1

Before Heating After Heating


(e) Diagram 3.2 shows the effect of heat on the bimetallic strip

(i) Why does the metallic strip bend after heating?

………………………………………………………………………………….…………..

………………………………………………………………………………………………

[1 mark]

(ii) Diagram 3.3 shows bimetallic strip used in a fire alarm. Label P and Q in the boxes provided so that fire alarm system can function.

(iii) What causes the alarm to ring when the bimetallic strip bends?

……………………………………………………………………………………………………..

[1 mark]

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Contact screw

Metal P

Metal Q

Before heating After heating

Diagram 3.2

Fire alarm rings

Power supply

Emergency light

Contact point

Diagram 3.3


4. (a) Diagram 4.1 shows two shirts of different colours which are being dried under the same conditions.

(i) Based on your observations in Figure 8.1, state the difference in the time taken for the shirts to dry in Situation A and Situation B.

… …………………………………………………………………………………………………

……………………………………………………………………………………………………

[1 mark]

(ii) What inference can be made based on Situation A and Situation B in Diagram 4.1?

…….. ……………………………………………………………………………………………..

……………………………………………………………………………….. …………………….

[1 mark]

(b) Diagram 4.2 shows an experiment to study the absorption of heat by different surfaces. The apparatus is being heated for 5 minutes and the thermometer reading in each minute is recorded in the table 4.3 below. The final thermometer reading is shown.

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Diagram 4.1

Situation A Situation B

Black shirt White shirt


Time of heating,

t (minutes)

Reading of thermometer X

T, (C)

Reading of thermometer Y

T, (C)

0 35 35

1 36 35

2 38 36

3 40 36

4 42 37

5

Table 4.3

(i) State the following variables.

Controlled variable : ………………………………………………………………………….

Manipulated variable: …………………………………………………………………………

Responding variable: ………………………………………………………………………..

[3 marks](ii) State the hypothesis of this experiment.

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Diagram 4.2

40 35


………….......................................................................................................................

…………..…………………………………………………………………………….. ………

[1 mark]

(iii) Record the temperature reading in the table 4.3.[1 mark]

(iv) Based on the information in Table 4.3, plot a graph to show the relationship between the time of heating, t and the thermometer reading.

[2 marks]

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(v) Based on the graph, what is the relationship between the time, t and the temperature, T?

………………………………………………………………………………………………….

………………………………………………………………………………………………….

[1 mark]

(vi) Predict what will happen to the thermometer X reading after 5 minutes.

…………………………………………………………………………………………………

…………………………………………………………………………………………………

[1 mark]

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5. Diagram 5.1 shows an activity to compare the heat conductivity of three different metal rods, P, Q and R.

The rods are heated equally at one end. The time taken for the thumbtacks to drop is given in Table 5.2.

Metal rod Time taken for thumbtacks to drop (s)P 90Q 150R 110

Table 5.2

(a) How is heat transferred through the metal rods?

……………………………………………………………………………………………………….

[1 mark]

(b) (i) Which metal rod transfer heat the fastest?

……………………………………………………………………………………………………

[1 mark]

(ii) Explain your answer in (b)(i).

………………………………………………………………………………………………….

[1 mark]

(c) Arrange P, Q and R according to their heat conductivity in ascending order.

……………………………………………………………………………………………………….

[1 mark]

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Rod P

Rod Q

Rod R

Wax

Thumbtack

Diagram 5.1


(d)(i) Which of the metals, P, Q, or R is the best material for making a frying pan?

………………………………………………………………………………………………….

[1 mark]

(ii) Give one reason for your answer in (d)(i).

……………………………………………………………………………………………………

…………………………. ……………………………………………………………………….

[1 mark]

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chapter 7 heat

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