1. The document discusses key concepts in heat and thermodynamics including temperature, heat transfer mechanisms, thermal expansion, and phase changes. 2. It provides examples of problems and their solutions involving concepts like specific heat, latent heat, temperature conversions, and heat transfer calculations. 3. The key heat transfer mechanisms of conduction, convection, and radiation are explained through examples of how they apply to insulating houses and minimizing energy costs.

1. HEAT AND
THERMODYNAMICS
By : Arra C. Quitaneg

2. HEAT AND THERMODYNAMICS
OBJECTIVES:
- Define heat, temperature, specific heat
capacity.
- Solve problems on thermal expansion heat
transfer, quantity of heat and temperature
conversion.
- Describe different heat transfer mechanisms.
- Apply concepts on building or house design.

3. What is temperature?

4. TEMPERATURE
• http://ippex.pppl.gov/interactive/fusion/contr
olatomtemp.html

5. - A quantity that tells how warm or cold an object is
with respect to a standard
- related to the random motion of the molecules in
a substance.
- it is proportional to the average kinetic energy of
molecular translational motion.

7. Kelvin Scale
named after British
physicist Lord Kelvin
Zero is assigned to the
lowest possible
temperature absolute
zero
- 2730C

8. Celsius Scale
Named after a Swedish
astronomer Anders
Celsius
Zero is assigned to the
temperature at which
water freezes, and 100 is
the temperature at
which water boils.
Farenheit Scale
Named after a German
physicist G.D Farenheit
32 is assigned to the
temperature at which
water freezes
212 is assigned to the
temperature at which
water boils.

9. TEMPERATURE SCALE
CONVERSION
• °C = K - 273.15°
• K = °C + 273.15
°C = (°F - 32°)/1.8
°F= 1.8•°C + 32°

10. • Internal energy =
the grand total of
all energies inside a
substance.

11. THERMAL EQUILIBRIUM
Objects that are in thermal equilibrium are at
the same temperature.
A B

13. THERMAL EXPANSION
Why are there thermal
expansion joints in
roads?
-When the temperature of a substance is
increased, molecules or atoms move faster and tend to
move farther apart, resulting to an expansion of the
substance.
-Expansion of liquids is greater than the expansion
of solids.

14. How does a
thermometer
work?
Is the
expansion of
the liquid
same as that
of the glass?

15. THERMOMETER

16. Linear Expansion
• ∆L = change in length
• = coefficient of linear expansion
• L0 = initial length of the material
• ∆T = is the change in temperature

17. Volume expansion
• ∆V = change in volume
• = coefficient of volume expansion
• V0 = initial volume of the material
• ∆T = is the change in temperature

18. Problem-solving
• You place a small piece of
melting ice in your
mouth. Eventually, the
water all converts from
ice at T1= 320F to body
temperature T2= 98.60F.
Express the temperatures
in 0C and in K and find T
in both cases.
Solution:
0F to 0C
°C = (°F - 32°)/1.8
°C = (32°F - 32°)/1.8
= 0°C
°C = (98.6°F - 32°)/1.8
= 37°C
K = °C + 273.15
K = 0°C + 273.15 = 273.15K
K = 37 °C + 273.15 =
310.15K
Solution:
T = T2-T1
T = 370C - 00C
= 370C
T = 310.15 K – 273.15K
= 37 K

19. Problem-solving
• A surveyor uses a
steel measuring tape
that is exactly 50 m
long at a temperature
of 200C. What is its
length on a hot
summer day when
temperature is 350C.
steel = 1.2x10-5 K-1
• SOLUTION
• Lf – L0= L0 T
• Lf = L0 T + L0
• Lf = L0 ( T + 1)
• Lf = 50m (1.2x10-5 K-1 15K + 1)
• Lf = 50.009 m

20. • A gas flask with volume
200cm3 is filled to the
brim with mercury at
200C. How much
mercury overflows
when the temperature
of the system is raised
to 1000C? glass = 0.4
x10-5 K-1
mercury = 18 x
10-5 K-1
.
Solution:
glass = 3
Vglass = 3(0.4 x10-5 K-1 ) 200 cm3 80K
Vglass = 0.192 cm3
Vmercury = (18 x10-5 K-1 )
200 cm3 80K
Vmercury = 2.88 cm3
Solution:
Volume of mercury
which overflows
Vmercury - Vglass
=2.88 cm3 - 0.192 cm cm3
= 2.69 cm3

21. • Solution
• = L/L0 T
• = (40.148cm – 40.125cm) /
(40.125cm)(450C - 200C)
• = 2.29 x 10-5 K
• A metal rod
is40.125 cm long
at 200C and
40.148 cm long at
450C. Calculate
the average
coefficient of
linear expansion
of the rod.

22. Seatwork
1. A gas flask with volume 1000cm3 at 0 0C is
completely filled with mercury at this
temperature. How much mercury overflows if
the flask is warmed at 550C? glass = 0.4 x10-5
K-1
mercury = 18 x 10-5 K-1
2. The steel bed of suspension bridge is 200 m
long at 200C. If the extremes of temperature
to which it might be exposed are – 30 0C to +
400C, how much will it contract and expand?

23. 3. What is the change in length of a column of
mercury 3.0 cm long if its temperature
increases from 370 to 400 C? mercury = 60 x10-6
/ C0

24. THERMAL EXPANSION OF WATER

25. THERMAL EXPANSION OF WATER
Water is densest at 40C.
As the water is cooled below
4 deg C however, it expands!
If water were like most
other materials, the very
cold water would sink and
lakes would freeze from the
bottom up.

26. Why is it that some
foods remain hotter
much longer than
others?

27. • The quantity of heat required to change the
temperature of a unit mass of the substance
by 1 deg Celsius.
• Thermal inertia- resistance of a substance to
change its temperature

28. Quantity of Heat
• Q = amount of heat
• m= mass
• c=specific heat capacity
• T = change in temperature
• If Q and T 0, heat enters the body and its
temperature increases
• If Q and T 0, heat leaves the body and its
temperature decreases

29. Calorimetry and Phase Change
• Calorimetry – measuring heat
• Phase – state of matter
Q= quantity of heat
m=mass
L = latent heat of fusion or
vaporization

30. Phase change

31. Evaporation
How is fire-walking
possible?
Why do dogs
pant?

32. Evaporation
 Evaporation is a change of phase from liquid
to gas.
 Cooling process
 Endothermic – heat is bsorbed

33. I really
love
mud!!!

34. CONDENSATION
Change of phase from gas to liquid
Warming process
Exothermic = heat is released
Steam burn is more damaging than a burn
from boiling water

35. It is warm inside
the shower room
after taking a
bath because
condensation is a
warming process.

36. Problem- solving:
1. How much heat is required to raise the
temperature of an empty 20 kg vat made of
iron from 100C to 900C?What if the vat is
filled with 20 kg of water? Ciron = 450 J/kgC0
C water = 41860C
2. What is the specific heat of a metal substance
if 135kJ of heat is needed to raise 5.1 kg of
the metal from 200C to 300C?

37. PROBLEM SOLVING
3. How much energy does a refrigerator have to
remove from 1.5 kg water at 200C to make ice
at -120C? Lf =334x103 J/kg, Cice = 2100
J/kgC0
4. How much heat is needed to melt 16.5 kg of
silver that is initially at 200C? Melting pt of
silver = 960.80C Lf =88.3x103 J/kg
Csilver=234 J/kgC0

38. 5. An ice cube tray of negligible mass
contains 0.350 kg of water at 180C . How
much heat must be removed to cool the
water at 00C and freeze it?
6. How much heat is required to convert 12.0
g ice at -100C to steam at 1000C? Lv =2256
x103 J/kg Csteam =2010 J/kgC0

39. Answers
1. A) 6, 697, 600 Joules, b) 720 000 Joules
2. 2, 647 Joules
3. 664, 380 Joules
4. 5, 089, 378.8 Joules
5. 143, 271.8 Joules
6. 36, 355.2 Joules

41. • Heat is transferred from
hotter substance to colder
substance upon contact with
each other.
• Heat conduction occurs by
electron and molecular
collisions.
• Metals are good conductors
of heat.

42. Conduction
• http://www.absorblearning.com/media/attac
hment.action?quick=aj&att=750

43. Particle to particle interaction

44. • Liquids and
gases, are poor
conductors.
• Air is a very poor
conductor.

45. CONDUCTION

47. Does it feel so
cold inside an
ice hotel?
No, it’s not that
cold. Thanks to
the poor heat
conductivity of ice


48. Snow is a poor conductor
of heat.
Snow does not provide
heat, it slows down the
loss of heat they
generate.
Insulating materials delay
the transfer of heat.

49. Thanks to
snow’s poor
heat
conductivity! 

50. In desert regions
that are hot in the
daytime and cold at
nightime, the walls
of houses are often
made of mud. Why
is it important that
the mud walls be
thick?

51. • Liquids and gases transmit heat by convection
• Heat transfer by actual motion of the fluid –
by currents.

52. CONVECTION AND HOT WATER
BASED BOARDS
What will happen if the heating system is not
placed on the floor?

53. • Heat transfer in an empty space.
• Energy radiated is radiant energy.

54. Absorber and Emitter of radiation
• A perfect absorber reflects no radiant
energy and appears perfectly black
• Good reflectors are poor absorbers

55. Think…think…think…
• Why does the evaporation of water cool the air near
the water’s surface?
• What color should you paint your house (light or
dark colored) to stay cooler in summer. Why?
• Next time you go to a coffee shop,
when should you pour the creamer
on the coffee to maintain its hotness?
(immediately after receiving it or when
you are about to drink it)

56. • A tile floor may feel uncomfortably cold to your bare
feet, but a carpeted floor in an adjoining room at the
same temperature feels warm. Why?
• Nowadays, in the Philippines, it is extremely hot
during summer. You won’t even notice a difference in
temperature inside and outside your house. As an
architect, what can you suggest to minimize heat
transfer from the surrounding to the house? When
you give your suggestion, environmental
considerations should not be taken for granted.

59. • The different mechanism of heat transfer
become important in reducing heating and
cooling costs in buildings.
• Reducing this flow of heat saves money.
• Putting insulation in the walls and ceilings
reduces conduction.
House insulation

60. • Using thicker insulation in the ceiling
counteracts one effect of convection.
• Using window shades, and canopies to keep
direct sunlight out during the summer reduces
heat transfer by radiation.