2. At the end of this unit you will:
a. Explain the difference and relationship of
temperature and heat
b. Explain the Zeroth Law of Thermodynamics
c. Relate the dimensions of an object change as a
result of a temperature change
d. Define heat transfer and its application to
various phenomena
e. Analyze and solve problems that involve heat
flow, temperature changes, and changes of
phase
3. SELF-CHECK QUESTIONS
1. Is heat and temperature the same concept?
2. Is it correct to say that objects emit heat and
cold objects emit cold?
3. Is it true that a blanket give us heat?
4. What direction does heat flow in?
5. What are the phase changes?
4. Concept Exploration
• Heat is thermal energy transferred from a warmer body
or system, to a colder one. So, one system releases
heat and the other one absorbs it.
• This thermal transfer will stop when both systems have
the same temperature (thermal equilibrium)
• Unit of measures for heat:
- 1 cal = 4.186 Joules (J)
- 1 kcal = 1000 cal = 4186 J
- 1 BTU = 778 ft.lb = 252 cal =1055 J
HEAT AND
TEMPERATURE
5. Concept Exploration
• Temperature is the amount of heat in a body or
system.
• The instrument that measures temperature is the
thermometer. There are three scales to measure
temperature:
Celsius scale- the most common scale.
C= 5/9 (F-32)
Fahrenheit scale – used in English speaking countries
F= 9/5 C+32
Kelvin scale – used by scientists.
K= C+ 273.15
HEAT AND
TEMPERATURE
6. How does heat transfer?
- There are three ways for heat to be
transferred, depending on the
material:
Conduction: this process occurs
in most solids. Heat is transferred
by direct contact.
Convection: occurs in liquids and
gases. Heat is transferred by the
movement of currents
Radiation: is the transfer of heat
by electromagnetic waves. contact
between the source and the
heated substances is not
necessary, so is the way heat
transfers in the universe.
7. Quantity of HEAT
• It is observed that a higher temperature object which is
in contact with a lower temperature object will transfer
heat to the lower temperature
• Heat flows from higher temperature to lower
temperature
8. Quantity of HEAT
• The quantity of heat Q required to increase the
temperature of a mass m of a certain material from T1
to T2 is found to be
• Approximately proportional to the temperature change
T = T2-T1
• It is also proportional to the mass m of material
• The quantity of heat needed also depends on the
nature of the material;
9. Quantity of HEAT
• Putting all these relationships together we have:
- Where c is called the specific heat of water. The specific
heat of water is approximately 4190 J/kg.K
13. 4th law of Thermodynamics
• “Zeroth Law” The First and Second
Laws were well entrenched when an
additional Law was recognized (couldn’t
renumber the 1st and 2nd Laws)
14. • If objects A and B are each in thermal
equilibrium with object C, then A and B are
in thermal equilibrium with each other
• Allows us to define temperature standard
Heat is the energy transferred
Temperature is equal to its’
internal energy
17. Phase Changes
•We use the term phase to describe a
specific state of matter, such as a
solid, liquid, or gas
•A transition from one phase to
another is called a phase change or
phase transition.
18. •A substance may absorb heat without an
increase in temperature by changing from
one physical state (or phase) to another,
as from
• a solid to a liquid (melting),
• a solid to a vapour (sublimation),
• a liquid to a vapour (boiling), or
• one solid form to another (usually called a
crystalline transition)
Phase Changes
19. • A familiar example of a
phase change is the
melting of ice.
• When we add heat to ice
at and normal
atmospheric pressure,
the temperature of the
ice does not increase.
Instead, some of it melts
to form liquid water.
20. • If we add the heat
slowly, to maintain the
system very close to
thermal equilibrium,
the temperature
remains at 0°𝐶 until all
the ice is melted
21. • The effect of adding heat
to this system is not to
raise its temperature but
to change its phase from
solid to liquid.
22. • To change 1 kg of ice at
0°𝐶 to 1 kg of liquid
water at and normal
atmospheric pressure
requires 3.34 × 105
𝐽 of
heat.
• The heat required per
unit mass is called the
heat of fusion (or
sometimes latent heat of
fusion), denoted by 𝐿 𝑓
23. •More generally, to
melt a mass m of
material that has a
heat of fusion
requires a quantity of
heat Q given by
𝑄 = ± 𝑚𝐿 𝑓
24. • for boiling or evaporation,
the corresponding heat
(per unit mass) is called the
heat of vaporization
27. Example
• A copper calorimeter can with mass
0.100 kg contains 0.160 kg of water and
0.0180 kg of ice in thermal equilibrium
at atmospheric pressure. If 0.750 kg of
lead at a temperature of 255℃ is
dropped into the calorimeter can, what
is the final temperature?
• Assume that no heat is lost to the
surroundings.
28. Concept Summary
• Heat and temperature are of different concepts but
interrelated.
• Heat is a thermal energy transferred from a warmer body or
system, to a colder one. Can be measured in two units: joule
and calorie
• Temperature is the amount of heat in a body or system. The
three scales to measure temperature: Celsius scale, Fahrenheit
scale and Kelvin scale.
• There are three ways for heat to transfer namely; conduction,
convection and radiations.
• Heat flows from higher temperature to a lower temperature.
• The quantity of heat can be computed using the formula
𝑸 = 𝐦𝐜∆𝑻 where m mass; c stands for the specific heat and
∆𝑻 for the change in temperature.
29. Concept Summary
• Zeroth Law states that if objects A and B are each
thermal equilibrium with object C, then A and Ba re in
thermal equilibrium with each other.
• Calorimetry means measuring heat.
• A transition from one phase to another is called a phase
change or phase transition.
• The effect of adding heat to the system is to raise its
temperature not to change its phase from solid to liquid.
• The heat required per unit mass is called the heat of
fusion (Lf).
• For evaporation the corresponding heat is called the
heat of vaporization (Lv).
31. https://play.kahoot.it/#/gameover?quizId=b76
c1da1-d9d0-43df-ab50-17b42d1ddff5
How to play this game?
Procedure:
1. Click the link of the game;
https://play.kahoot.it/#/gameover?quizId=b76c1da1-d9d0-43df-ab50-
17b42d1ddff5 and proceed whether it is a player vs player or a team
game quiz.
2. Any one can join the game as long as they have their own mobile phones
connected to kahoot.com online(where they can search on google. They
can join the game through typing the game pin of the above game ,
381134.
3. As long as everyone already join the game. You can now click the start
button.
4. Everyone must look on the screen (laptop) on the questions but you can
click the choices of your answer on your mobile phone.
5. The scoreboard will appear after every item. You can monitor your score
then and check for the right answers.
6. This game will declare the winner after the game. Enjoy! Join the game
now! The questions are about heat and temperature concepts.
32. Enrichment Activities
Kindly, refer to the file of the experiment click
the like emoji below :
There are three
experiments here!
1. Heat Experiment
2. Vacuum in a glass
3. Phase changes
You can choose one for
your experiment!
33. You may click this link: https://phet.colorado.edu/en/simulation/energy-
forms-and-changes
34. Questions:
1. What happen to the molecules of water, brick or
iron when you raise its temperature?
2. What about when you lower its temperature?
3. State the relationship of the temperature and the
molecules of the materials: iron, brick and water,
35. Check your understanding
We are going to have a quiz bowl about Heat and
Temperature. Please group yourselves by 5.
To start, please
click me!
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body)
