1. 2.3 Heat capacity and specific heat capacity
A magic balloon
Energy transfer and temperature change
Heat capacity
Check-point 3
Specific heat capacity
Check-point 4
‘Mixtures’
Importance of high specific heat capacity of water
Check-point 5 1 2 3 4 5
Book 1 Section 2.3 Heat capacity and specific heat capacity

2. Book 1 Section 2.3 Heat capacity and specific heat capacity
A magic balloon
Video
2.1 Magic balloon
Why did the balloon not pop?
any relation to water?
Book 1 Section 2.3 Heat capacity and specific heat capacity

3. Book 1 Section 2.3 Heat capacity and specific heat capacity
A magic balloon
This is because…
The balloon was filled with water.
But…
Why can water prevent the balloon from popping?
Book 1 Section 2.3 Heat capacity and specific heat capacity

4. 1 Energy transfer and temperature change
It takes a longer time to heat a pot of water…
to a higher temperature
of greater mass
Book 1 Section 2.3 Heat capacity and specific heat capacity

5. Book 1 Section 2.3 Heat capacity and specific heat capacity
1 Energy transfer and temperature change
Relationship between energy transferred, temperature change and mass
Expt 2a
Book 1 Section 2.3 Heat capacity and specific heat capacity

6. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2a
Relationship between energy transferred, temperature change and mass
Set up the apparatus.
How is the energy transferred by the heater to the water related to the temperature change and the mass of water?
Book 1 Section 2.3 Heat capacity and specific heat capacity

7. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2a
Relationship between energy transferred, temperature change and mass
Video
Video
2.2 Expt 2a - Relationship between energy transferred, temperature change and mass
Book 1 Section 2.3 Heat capacity and specific heat capacity

8. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2a
Relationship between energy transferred, temperature change and mass
Precautions:
Immerse the heating part of the heater totally in water before turning it on.
Totally immerse the heating part of the heater in water.
Stir the water before recording the temperature.
Book 1 Section 2.3 Heat capacity and specific heat capacity

9. Book 1 Section 2.3 Heat capacity and specific heat capacity
1 Energy transfer and temperature change
Expt 2a shows that:
Q  ∆T , for constant m
Q : energy transferred, ∆T : temperature change
More energy is needed to produce larger ∆T for the same mass.
Book 1 Section 2.3 Heat capacity and specific heat capacity

10. Book 1 Section 2.3 Heat capacity and specific heat capacity
1 Energy transfer and temperature change
Expt 2a shows that:
Q ∝ m , for constant ∆T
Q : energy transferred, m : mass
More energy is needed to produce the same ∆T for a larger mass.
Book 1 Section 2.3 Heat capacity and specific heat capacity

11. Book 1 Section 2.3 Heat capacity and specific heat capacity
Energy transferred Q to a body (of a fixed mass) ∝ its temperature change ∆T Q ∆T
Q = C ∆T or C =
C : heat capacity
(constant, unit: J C-1)
The heat capacity of a body is the energy transferred by heating needed to raise the temperature of that body through 1 C.
Book 1 Section 2.3 Heat capacity and specific heat capacity

12. Book 1 Section 2.3 Heat capacity and specific heat capacity
When the same amount of energy is supplied by heating to:
a glass of water
a pool of water
The change in temp is different
 they have different heat capacities
Heat capacity of water
Example 2
Book 1 Section 2.3 Heat capacity and specific heat capacity

13. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 2
Heat capacity of water
In order to heat up the water from 20 C to 25 C in:
a glass, 4 kJ of energy is needed.
a pool, 5  107 kJ of energy is needed.
What are the heat capacities of water in the above two cases?
Book 1 Section 2.3 Heat capacity and specific heat capacity

14. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 2
Heat capacity of water
Heat capacity of the glass of water = Q T =
4  103
25  20
= 800 J C1
Heat capacity of the pool of water = Q T =
5  1010
25  20
= 1010 J C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

15. Book 1 Section 2.3 Heat capacity and specific heat capacity
Heat capacities of two metal blocks
Example 3
Book 1 Section 2.3 Heat capacity and specific heat capacity

16. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 3
Heat capacities of two metal blocks
Metal block
Mass
Initial temp
Final temp
Energy required
Aluminium
1 kg
20 C
25 C
4500 J
Lead
5 kg
3250 J
What are the heat capacities of the two bodies?
Book 1 Section 2.3 Heat capacity and specific heat capacity

17. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 3
Heat capacities of two metal blocks
Heat capacity of the aluminium block = Q T =
4500
25  20
= 900 J C1
Heat capacity of the lead block = Q T =
3250
25  20
= 650 J C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

18. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 3 – Q1
A burner transfers J of energy to raise the temperature of an iron block by 80 C. What is the heat capacity of the iron block?
A 2400 J C-1
B 3000 J C-1
C J C-1
D J C-1
Book 1 Section 2.3 Heat capacity and specific heat capacity

19. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 3 – Q2
A heater transfers 500 kJ of energy to some water at 30 C. Heat capacity of the water is J C-1.
Final temperature of the water = ?
A 80 C
B 50 C
C 20 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

20. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 3 – Q3
In an experiment, three different pieces of metal are heated:
Gold
Silver
Copper
Mass (kg) 1 5 3
T (C) 10
Energy required (J)
645
5850
11 540
Which piece of metal has the highest heat capacity?
A Gold
B Silver
C Copper
Book 1 Section 2.3 Heat capacity and specific heat capacity

21. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 3 – Q4
Calculate the amount of energy required to heat up a glass of milk from 20 C to 60 C.
(Heat capacity of the glass of milk = 2400 J C1)
Energy required Q
= C T
(60  20)
2400
= _______  _________ J
= _______
Book 1 Section 2.3 Heat capacity and specific heat capacity

22. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 3 – Q5
The fig on the right shows the Q-T graph of an object.
What is the heat capacity of this object? = Q T =
50  1000 – 0
200  0 C
= 250 J C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

23. Book 1 Section 2.3 Heat capacity and specific heat capacity
Heat capacity of a substance increases with its mass.
 More convenient to use specific heat capacity
The specific heat capacity of a substance is the energy transferred by heating needed to raise the temperature of 1 kg of that substance through 1 C.
Book 1 Section 2.3 Heat capacity and specific heat capacity

24. Book 1 Section 2.3 Heat capacity and specific heat capacity
Recall that Q ∝T and m. Q
m∆T
Q = mc∆T or c =
c : specific heat capacity
(unit: J kg-1 C-1)
Compared with the equation of heat capacity:
C m
c = or C = mc
Book 1 Section 2.3 Heat capacity and specific heat capacity

25. Book 1 Section 2.3 Heat capacity and specific heat capacity
Energy needed to raise temperature
Example 4
Book 1 Section 2.3 Heat capacity and specific heat capacity

26. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 4
Energy needed to raise temperature
Calculate the energy needed to raise the temperature of 5 kg of aluminum from 20 C to 100 C.
(Specific heat capacity of aluminium = 900 J kg-1 C-1)
Q = mc ∆T
= 5  900  (100  20)
= J
Book 1 Section 2.3 Heat capacity and specific heat capacity

27. Book 1 Section 2.3 Heat capacity and specific heat capacity
Specific heat capacities of some substances:
Substance
c / J kg-1 C-1
Water
4200
Aluminium
900
Glass
600
Iron
480
Copper
370
Lead
130
Note: Water has a high specific heat capacity.
Book 1 Section 2.3 Heat capacity and specific heat capacity

28. Book 1 Section 2.3 Heat capacity and specific heat capacity
2.1 Measuring specific heat capacity of water
Simulation
Measuring the specific heat capacity of water
Expt 2b
Book 1 Section 2.3 Heat capacity and specific heat capacity

29. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2b
Measuring the specific heat capacity of water
Set up the apparatus.
mass of water =0.2 kg
heat up by 10 C
Find:
energy required
specific heat capacity of water
2.3 Measuring the specific heat capacity of water
Video
Book 1 Section 2.3 Heat capacity and specific heat capacity

30. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2b
Measuring the specific heat capacity of water
Precautions:
Immerse the heating part of the heater totally in water before turning it on.
Totally immerse the heating part of the heater in water.
Stir the water after switching off the heater and record the highest temperature.
Book 1 Section 2.3 Heat capacity and specific heat capacity

31. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 5
Specific heat capacity of water
Book 1 Section 2.3 Heat capacity and specific heat capacity

32. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 5
Specific heat capacity of water
In an experiment, the following results are obtained:
Mass of water = 0.2 kg
Initial joulemeter reading = J
Final joulemeter reading = J
Initial temperature = 20 C
Final temperature = 37 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

33. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 5
Specific heat capacity of water
(a) Find the specific heat capacity of water.
Q = – = J
∆T = 37 – 20 = 17 C
Specific heat capacity of water Q
m∆T = =
15 000
0.2  17
= 4410 J kg1 C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

34. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 5
Specific heat capacity of water
(b) State two sources of error. How do they affect the experiment result?
Sources of error:
Energy lost to the surroundings
Some energy is used to heat up the cup, the stirrer and the thermometer.
Due to these errors,
experimental value > actual value.
Book 1 Section 2.3 Heat capacity and specific heat capacity

35. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 5
Specific heat capacity of water
(c) How can we improve the accuracy of the experiment?
Wrap the polystyrene cup with cotton wool
to reduce energy lost to the surroundings.
Book 1 Section 2.3 Heat capacity and specific heat capacity

36. Book 1 Section 2.3 Heat capacity and specific heat capacity
Simulation
2.2 Measuring specific heat capacity of metal
Measuring the specific heat capacity of aluminium
Expt 2c
Book 1 Section 2.3 Heat capacity and specific heat capacity

37. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2c
Measuring the specific heat capacity of aluminium
Set up the apparatus.
mass of aluminium = 1 kg
- heat up by 10 C
Find:
energy required
- specific heat capacity of aluminium
2.4 Expt 2c - Measuring the specific heat capacity of aluminium
Video
Book 1 Section 2.3 Heat capacity and specific heat capacity

38. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2c
Measuring the specific heat capacity of aluminium
Precautions:
1 Add a few drops of oil to the holes in the aluminium block.
2 Place the aluminium block on a polystyrene tile.
3 Do NOT switch on the heater unless its heating part is in contact with the aluminium block.
4 Do NOT record the temperature immediately after the heater is switched off.
Book 1 Section 2.3 Heat capacity and specific heat capacity

39. Book 1 Section 2.3 Heat capacity and specific heat capacity
Specific heat capacity of aluminium
Example 6
Book 1 Section 2.3 Heat capacity and specific heat capacity

40. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 6
Specific heat capacity of aluminium
The following results are obtained in an experiment:
Mass of aluminium = 1 kg
Initial joulemeter reading = J
Final joulemeter reading = J
Initial temperature = 28.5 C
Final temperature = 35.0 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

41. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 6
Specific heat capacity of aluminium
(a) Find the specific heat capacity of aluminium.
Q = – = 6600 J
∆T = 35.0 – 28.5 = 6.5 C
Specific heat capacity of aluminium Q
m∆T = =
6600
1  6.5
= 1020 J kg1 C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

42. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 6
Specific heat capacity of aluminium
(b) Standard value of the specific heat capacity of aluminium = 900 J kg1 C1
Result in (a) = 1020 J kg1 C1
% error = ?
1020 – 900
900
% error =
 100%
= 13.3%
Book 1 Section 2.3 Heat capacity and specific heat capacity

43. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 6
Specific heat capacity of aluminium
(c) How can we improve the accuracy of the experiment?
Wrap the aluminium block with cotton wool
to reduce energy lost to the surroundings.
Book 1 Section 2.3 Heat capacity and specific heat capacity

44. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 4 – Q1
Which of the following is/are heated up by the heater?
(1) Thermometer
(2) Aluminium block
(3) Polystyrene tile
A (1) only
B (2) only
C (1) and (3) only
D (1), (2) and (3)
Book 1 Section 2.3 Heat capacity and specific heat capacity

45. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 4 – Q2
In Expt 2b, the following results are obtained:
Temperature /C
Joulemeter reading / J
Initial 23
34 000
Final 47
56 000
Mass of water = 0.2 kg Specific heat capacity of water = ? Q
m∆T = = – c
= 1020 J kg1 C1
0.2  (47 – 23)
Book 1 Section 2.3 Heat capacity and specific heat capacity

46. Book 1 Section 2.3 Heat capacity and specific heat capacity
4 ’Mixtures’
When two bodies that have different temperatures are put in contact,
energy is transferred from the hot body to the cold body.
energy lost by the hot body
energy gained by the cold body =
Book 1 Section 2.3 Heat capacity and specific heat capacity

47. Book 1 Section 2.3 Heat capacity and specific heat capacity
4 ’Mixtures’
After a certain time
hot
cold
same temperature
Energy flows from hot body to cold body
Transfer of energy stops; thermal equilibrium is reached
Book 1 Section 2.3 Heat capacity and specific heat capacity

48. Book 1 Section 2.3 Heat capacity and specific heat capacity
4 ’Mixtures’
It agrees with the law of conservation of energy:
The total amount of energy in a system is always constant.
2.3 Energy transfer between bodies at different temperatures
Simulation
‘Mixture’
Expt 2d
Book 1 Section 2.3 Heat capacity and specific heat capacity

49. Book 1 Section 2.3 Heat capacity and specific heat capacity
Experiment 2d
‘Mixture’
Measure the mass and temperature of a cup of cold water and a cup of hot water.
Quickly mix the two cups of water and measure the temperature of the ‘mixture’.
Find - the energy lost by the hot water - the energy gained by the cold water
Video
2.5 Expt 2d - ‘Mixture’
Book 1 Section 2.3 Heat capacity and specific heat capacity

50. Book 1 Section 2.3 Heat capacity and specific heat capacity
4 ’Mixtures’
Final temperature of ‘mixture’
Example 7
Book 1 Section 2.3 Heat capacity and specific heat capacity

51. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 7
Final temperature of ‘mixture’
0.5 kg
90 C
What is the temperature of the ‘mixture’?
0.2 kg
15 C
Let T be the temperature of the mixture.
Fall in temperature of hot water = (90 – T ) C
Rise in temperature of cold water = (T – 15) C
Book 1 Section 2.3 Heat capacity and specific heat capacity

52. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 7
Final temperature of ‘mixture’
energy gained by cold water
energy lost by hot water =
0.5 × 4200 × (90 – T ) = 0.2 × 4200 × (T – 15)
0.5 × (90 – T ) = 0.2 × (T – 15)
45 – 0.5T = 0.2T – 3
T = 68.6
Final temperature of the ‘mixture’ = 68.6 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

53. Book 1 Section 2.3 Heat capacity and specific heat capacity
4 ’Mixtures’
Boiled shrimp
Example 8
Book 1 Section 2.3 Heat capacity and specific heat capacity

54. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
Mother puts 0.6 kg of shrimp at 4 C into 1 kg of water at 25 C.
Temp of the ‘mixture’ just after mixing = 18 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

55. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
(a) What is the specific heat capacity of the shrimp?
Assume: energy loss = 0
Energy gained by the shrimp
= energy lost by the water
= mc ∆T
= 1  4200  (25  18)
= J
Book 1 Section 2.3 Heat capacity and specific heat capacity

56. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
Specific heat capacity of the shrimp Q
m∆T = =
29 400
0.6 x (18 – 4)
= 3500 J kg–1 C1
Book 1 Section 2.3 Heat capacity and specific heat capacity

57. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
(b) Explain how does the internal energy of the water change after the shrimp is added.
Temp of the water 
 Average KE of the water particles 
 Internal energy of the water 
Book 1 Section 2.3 Heat capacity and specific heat capacity

58. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
(c) If energy is transferred at a rate of 1.5 kW, time needed to reach 100 C = ? Assume: energy loss = 0
Energy needed to raise the temp of water to 100 C = mc∆T
= 1  4200  (100 – 18) = J
Energy needed to raise the temp of shrimp to 100 C = mc∆T
= 0.6  3500  (100 – 18) = J
Book 1 Section 2.3 Heat capacity and specific heat capacity

59. Book 1 Section 2.3 Heat capacity and specific heat capacity
Example 8
Boiled shrimp
Total energy transferred to the ‘mixture’ =
= J
By P = , Q t
t =
1500
= 344 s = 5.74 mins
It takes 5.74 mins for the ‘mixture’ to reach 100 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

60. Book 1 Section 2.3 Heat capacity and specific heat capacity
5 Importance of high specific heat capacity of water
Water has a very high specific heat capacity (4200 J kg–1 C–1).
Water can absorb or release a lot of energy with only a small temperature change.
 Useful in many areas
Book 1 Section 2.3 Heat capacity and specific heat capacity

61. Book 1 Section 2.3 Heat capacity and specific heat capacity
5 Importance of high specific heat capacity of water
a Water coolant
Water is used as a coolant in motor cars.
It takes in energy from the hot engine and carries it to the radiator and releases it to the air.
Energy given out by radiator
Heat removed from engine
air flows
pump
Book 1 Section 2.3 Heat capacity and specific heat capacity

62. Book 1 Section 2.3 Heat capacity and specific heat capacity
5 Importance of high specific heat capacity of water
b Regulating body temperature
About % of the mass of an average person is made up of water.
Its high specific heat capacity helps to keep our body temperature constant.
Video
2.6 Catch the fire
Book 1 Section 2.3 Heat capacity and specific heat capacity

63. Book 1 Section 2.3 Heat capacity and specific heat capacity
5 Importance of high specific heat capacity of water
c Climate effect
The temperature of seawater rises and falls much more slowly than that of the land.
Coastal areas:
daily temp difference much smaller than inland areas of the same latitude
cooler summers and milder winters
Book 1 Section 2.3 Heat capacity and specific heat capacity

64. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q1
Heat sink is a device for absorbing and dissipating heat.
Which of the following is/are true for a good heat sink?
A It has high specific heat capacity.
B It has large surface area.
C Both of the above.
Book 1 Section 2.3 Heat capacity and specific heat capacity

65. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q2
Metal plates A and B are made of the same material.
Plate A : mass = 0.6 kg, temp. = 10 C Plate B : mass = 1.5 kg, temp. = 50 C
After they are put in contact, temp of the plates = ?
A C
B C
C C
D C
Book 1 Section 2.3 Heat capacity and specific heat capacity

66. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q3
0.5 kg of ham at 5 C is put into 1 kg of water at 90 C.
Final temperature of the ‘mixture’ = 70 C
Specific heat capacity of water = 4200 J kg–1 C–1
What is the specific heat capacity of the ham?
Book 1 Section 2.3 Heat capacity and specific heat capacity

67. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q2
Let c be the temperature of the mixture.
energy lost by the water
energy gained by the ham =
0.5 × c × (70 – 5) = 1 × 4200 × (90 – 70)
32.5c =
c = 2580 J kg–1 C–1
Book 1 Section 2.3 Heat capacity and specific heat capacity

68. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q4
Amy is preparing a cup of instant noodles by adding 200 g of water at 90 C to 80 g of noodle at 20 C.
What will be the temperature of the mixture just after mixing?
Book 1 Section 2.3 Heat capacity and specific heat capacity

69. Book 1 Section 2.3 Heat capacity and specific heat capacity
Check-point 5 – Q4
(Specific heat capacity of water = 4200 J kg1 C1
Specific heat capacity of noodle = 2000 J kg1 C1)
Let T be the temperature of the ‘mixture’.
energy gained by noodles
energy lost by hot water =
0.2 × 4200 × (90 – T ) = 0.08 × 4200 × (T – 20)
– 840T = 160T – 3200
T = 78.8 C
Book 1 Section 2.3 Heat capacity and specific heat capacity

70. Book 1 Section 2.3 Heat capacity and specific heat capacity
The End
Book 1 Section 2.3 Heat capacity and specific heat capacity