specific heat capacity

1. 4.2 SPECIFIC HEAT CAPACITY
YOURTEACHER:
CIKGU SURIYATI YUSOFF
SM SAINS MUZAFFAR SYAH

2. LEARNING STANDARD
4.2.1 Explain heat capacity, C
4.2.2 Define specific heat capacity, c

3. The sun heats up the sand
and sea water at the same
period of time.
However, sand gets hot
quickly and sea water gets
hot slowly.

4. This can be explained
based on the concept
of heat capacity.
Different objects have
different heat capacity.
Sand has a low heat
capacity and gets hot
quickly.
Sea water has a high
heat capacity and gets
hot slowly.

5. During morning, a boy puts a pail
of water from a swimming pool
near the pool.
During afternoon, the boy puts
one hand into the pail and
another hand in the swimming
pool.
He observes that both
temperatures are different.
Water in the pail is hotter
than water in the pool.

6. The water in the pool and in the pail have
different heat capacity.

7. Water and cooking oil
which have the same mass
is heated with the same
amount of heat.
It is observed that the temperature
of the cooking oil rises faster than
the water temperature
Water and cooking oil have different
specific heat capacity.

8. Apakah maksud…..
Heat capacity? Specific Heat
Capacity?

9. Activity 1:
Aim: Investigate heat capacity
A pail of water from a swimming
pool has been left for several hours
beside the pool.
(a) Which water is hotter?
(b) Which water has smaller mass?
(c) Which water needs to be exposed to the
sunlight in a shorter time in order to raise its
temperature by 1 ⁰C?
Water in the pail
Water in the pail
Water in the pail

10. Activity 1:
Aim: Investigate heat capacity
(d) Which has larger heat capacity, water in
the pail or water in the swimming pool?
(e) Make an inference about relationship
between heat capacity and temperature
rises of a substance.
Water in the pool
The higher the heat capacity, the
lower the temperature rises.

11. Takrifkan muatan haba:
Heat Capacity, C on an object is the
quantity of heat needed to raise the
temperature of the object by 1°C.
C = Q Q = quantity of heat supplied
Δθ Δθ = change in temperature
Unit C = J ⁰C-1

12. Activity 1 Aim: Investigate heat capacity
2. When 2000 J of heat is supplied to objects X and Y, object X experience a
rise in temperature of 1 ⁰C and object Y by 2 ⁰C.
(a) What is heat capacity of?
(i) Object X? (ii) Object Y?
CX = 2000 J
1 ⁰C
= 2000 J ⁰C-1
CY = 2000 J
2 ⁰C
= 1000 J ⁰C-1
(b) Compare heat capacity
(c) Compare the rise in
temperature
(b) Which object is hotter
Heat capacity X >
heat capacity Y
Rise in temperature X
< peningkatan suhu Y
Object Y is hotter Object with high heat
capacity heats up slowly

13. Object A and B are made from aluminium but
have different heat capacity because
different masses.
Object A of mass
1 kg needs 900 J
of heat to rise up
temperature by
1 °C.
Object B of mass
2 kg needs 1800 J
of heat to rise up
temperature by
1 °C.
CA = 900 J ⁰C-1
CB = 1 800 J ⁰C-1
Heat capacity B > heat capacity A
Heat capacity for an object is higher when its
mass increases.

14. Both kettle P and Q is switched on to heat up
water until boiling.
(a) Which kettle boils for longer time?
(b) Which kettle has larger quantity of heat?
(c) Which kettle has larger heat capacity?
Kettle Q
Kettle Q
Kettle Q

15. (d) Make an inference about the relationship
between heat capacity and mass of a substance
(e) What factors affect the heat capacity?
The greater the mass, the greater
the heat capacity.
Mass Rises of temperature
Material of
substance

16. Activity 2 Aim: Investigate daily situations which involve
heat capacity
1. Explain why a cup of hot coffee can cause more injury
on a body than a drop of hot coffee.
Water from a cup of hot coffee
has higher heat capacity
compared to a drop of hot coffee
drop on a body.

17. 2. Explain why the metal parts of a car get hot
faster while the plastic and other material stay
at more bearable temperature
The dashboard of a car has a lower
heat capacity compared to the
cushion.
Absorption of heat energy from the
Sun causes the dashboard to get hot
faster compared to the cushion.
Activity 2 Aim: Investigate daily situations which involve
heat capacity

18. After being left to cool for some
time, the soup in a large bowl is
hotter compared to the same soup
in a small bowl.
The soup in the large bowl has
greater heat capacity. So it
cools down at slower rate.
Activity 2 Aim: Investigate daily situations which involve
heat capacity

19. 3. Explain why children like walking on the water
compare to the sand on hot day.
Sand and sea water receive the
same heat. Sand heats up faster and
sea water heats up very slow.
Sand has low heat capacity and
heats up faster. Water has high heat
capacity and heats up slowly.
Activity 2 Aim: Investigate daily situations which involve
heat capacity

20. We can touch the crust
Apple jam is very hot
4. Explain why the jam of a hot apple pie
burns but the crust can be eaten instantly.
It is easier to eat the
crust because it cools
down faster compared
to apple jam which is
still hot.
The crust and the apple
jam has different heat
capacity.
Heat capacity
of apple jam
is greater.
Activity 2 Aim: Investigate daily situations which involve
heat capacity

21. 5. A watermelon and sandwich are taken out from
a fridge. After 30 minutes, the watermelon is
cooler than the sandwich. Why does the
watermelon stay cool for a longer time than a
sandwich even tough both are taken out from
the same fridge?
Watermelon cools down faster
compared to the sandwich. Heat
capacity of the watermelon is
smaller, so the drops of temperature
is faster.
Activity 2 Aim: Investigate daily situations which involve
heat capacity

22. Activity 3 Aim: Investigate specific heat capacity
Different quantity of heat is needed to raise
the temperature by 1 ⁰C for two objects A and
C even though their masses are equal.
This is because the two objects are made from
different material. Different substance has
different specific heat capacity.
Which substance needs large amount of heat to
raise temperature by 1 ⁰C. Aluminium

23. 1 kg of plumbum (Pb) needs 130 J
of heat and 1 kg of Aluminium
needs 900 J of heat to raise the
temperature by 1 ⁰C.
Plumbum heats up faster than
Aluminium because it needs less
heat to raise temperature 1 ⁰C.
Activity 3 Aim: Investigate specific heat capacity

24. The quantity of heat needed to
raise the temperature of 1 kg
mass of the substance by 1 °C.
Heat
Mass
Rises of
temperature
Specific Heat
capacity
J
kg
°C
J kg-1°C-1
Definition of Specific Heat Capacity

25. Quantity of heat, J
Mass, kg
Specific heat capacity
Rise of temperature

26. 1 kg of aluminium needs
900 J of heat to raise its
temperature 1 °C
1 kg of water needs
4 200 J of heat to
raise its
temperature by 1 °C.
1. What is the meaning of the specific heat
capacity of aluminium 900 J kg-1 ⁰C-1?
2. What is the meaning of the specific
heat capacity of water is
4200 J kg-1 ⁰C-1?

27. m = 2 θ = 70-30 = 40 c = 500
Q = mcθ = (2)(500)(70 – 30) = 40,000 J
A metal has mass 2 kg. Calculate the amount of heat
that must be transferred to the metal to raise the
temperature from 30 ⁰C to 70 ⁰C.
(specific heat capacity of the metal = 500 J kg -1 ⁰C-1 )

28. m = 0.1 θ = 100-20 = 40 c = 129
Q = mcθ = (0.1)(129)(80) = 1 032 J
4. How many joules of energy are required to raise the
temperature of 100 g of gold from 20 ⁰C to 100 ⁰C?
(specific heat capacity of gold = 129 J kg-1 C-1)

31. Reduce heat lost to the surroundings
Value of c is bigger
There is heat lost, θ is
lower than the real value.
Formula c = Q
mθ,
so c bigger if θ small

32. Application of Specific Heat Capacity

33. Heats up and
cools faster
Sensitive to the
change of
temperature
Heats up and
cools slower
Can absorb a large
amount of heat.
Characteristics of a small value of specific heat capacity
Characteristics of big value of specific heat capacity
For example, water acts a heat reservoir as it can
absorb a great amount of heat before it boils.
Water is used as a cooling agent in a car radiator.

35. • Copper base :
• Low specific heat capacity. The pot
becomes hot very quickly. This enables
quick cooking of the food in the pot.
• High density. The heavier base ensures that
the pot is stable and will not topple over
easily. HANDLE :
Plastic
High specific heat capacity.
Poor heat conductor
BASE :
Copper
Low specific heat capacity.
Heats up very quickly.
BODY :
Aluminium
Low specific heat
capacity.
Heats up quickly
Cooking Pot

36. • Wooden handle:
• Large specific heat capacity. The handle
will not become too hot when heat is
absorbed.
• Poor conductor of heat.
• Alumni body:
• Relatively low specific heat capacity.
The pot becomes hot quickly.
• Low density so it will be lighter
• Does not react with the food in the pot
Body
Wooden
Handle
Base

37. Sea Breeze
1. During the day,
heat is absorbed by
the land and sea
2. Sea has a high
specific heat capacity
which temperature
increases slower.
3. Land has a low specific heat
capacity which temperature
increases faster. Land is
warmer than sea.
4. Warm air
above the land
rises. Becomes
low pressure
5. Cool air from the
sea (high pressure)
moves towards the
land as sea breeze.
The movement of cool
air from sea to land

38. Land Breeze
3. Hot air
above the sea
rises. Low
pressure
2. Sea is hotter than
the land which loses
heat slower.
1. Land loses heat faster than
sea at night due to its low
specific heat capacity
4. Cool air from
the land (high
pressure) moves
towards the sea
to replace the
rising air
The movement of cool
air from land to sea

39. Cooling system of a car engine
Water is used as coolant:
• High boiling point – not change to gas easily
• High specific heat capacity so can absorb a lot of
heat.
• Abundant, Economical –so cheaper & save cost

40. Pumps the water into
the engine block
Heat produced by the engine is
absorbed by the water
The hot water flows to the
radiator
Heat is released to the cooler air
that flows through the cooling fans.

42. Selection Building materials of traditional house in various
climate – warm climate
Materials for houses in warm
climate:
Reason:
Wood has a high specific heat
capacity and gets hot slowly.
In warm weather region, traditional
houses are built from wood which
functions as an insulator of heat from
the scorching sun.
kayu

43. Selection building materials of traditional houses in various
climate – cold climate
Materials for houses in cold
climate:
Reason:
Heat from fires lit in the wooden
houses cannot flow out because
wood functions as a good heat
insulator.
wood

44. Production of latest materials
in the construction of green buildings
Materials of the roof:
Reason:
Can reduce the absorption of heat
from surroundings to reduce the
temperature inside the building.
an insulating concrete roof
(Styrofoam boards which has high
specific heat capacity.

45. Outer layer of space capsules
Material:
Reason: it heats up slowly and high melting
point so it will not melt at high temperature.
The outer layer of a space capsule is
made from substance with a high
specific heat capacity
Space capsule on its journey back
to Earth encounters air resistance
when entering the atmosphere.
This friction increases the
temperature and causes the space
capsule to burn.

46. • Heat energy cannot be created.
• However, electrical energy, potential energy and
kinetic energy can be converted to heat energy.
Electrical energy
Heat energy
Pt = mcө
Potential energy Heat energy
mgh = mcө
Kinetic energy Heat energy
½ mv2 = mcө
heater
Power = P
Object falls from
a high position
Moving object
stopped
due to friction

47. Haba / heat :
Q = Pt = 1 000 x 5 x 60
= 300 000 J
Q = mcϴ
300 000 = (0.75)(4 200)ϴ
ϴ = 95.24⁰

48. Heat absorbed = heat released
0.2 x c x (ϴ- 40) = 0.8 x c x (100 - ϴ)
0.2ϴ - 8 = 80 - 0.8ϴ
ϴ = 80 + 8 = 88 ⁰C

51. Potential energy = heat
mgh = mcθ
→ 10 x 12 = 128 x ϴ
ϴ = 0.9375 ⁰C