3 methods of heat transfer

1. Have you ever grabbed theHave you ever grabbed the
handle of a hot metal pan?handle of a hot metal pan?
What did you feel?What did you feel?

2. Boiling a pot of water on theBoiling a pot of water on the
stove to cook some elbow pasta.stove to cook some elbow pasta.
What did you notice to theWhat did you notice to the
pasta?pasta?

3. We feel heat from the fire evenWe feel heat from the fire even
though we are not touching it.though we are not touching it.
How did it happen?How did it happen?

4. Heat TransferHeat Transfer
 The transfer of thermal energy betweenThe transfer of thermal energy between
substances due to difference in theirsubstances due to difference in their
temperature.temperature.
 HeatHeat is thermal energy that it is transmit fromis thermal energy that it is transmit from
warmer object to the cooler matterwarmer object to the cooler matter
Heat hot to cold

5. ConductionConduction
ConvectionConvection
RadiationRadiation
Method of HeatMethod of Heat
TransferTransfer

6. What is conduction?
Is the transferof heat through a
material by direct contact.

7. Prepare a coffee in same volume of hot 40ml water at 70Prepare a coffee in same volume of hot 40ml water at 70ºCºC
after 2 mins. measure the temperature of the coffeeafter 2 mins. measure the temperature of the coffee
using thermometer. Observe what happen?using thermometer. Observe what happen?
Prepare a coffeePrepare a coffee
Group 1 Group 2 Group 3
Styrofoam
cup
Metal
glass
Fiber
glass

8. Thermal Conductivity
 The thermal conductivity of a material describes
how well the material conducts heat.
Styrofoam
cup
Metal glassFiber glass

9. Conductors and InsulatorsConductors and Insulators
 Conductors — Materials that allow heat to— Materials that allow heat to
quickly pass throughout the material (suchquickly pass throughout the material (such
as metals).as metals).
 Insulators — Materials that do not allow— Materials that do not allow
heat to quickly pass throughout a materialheat to quickly pass throughout a material
(such as wood or plastic).(such as wood or plastic).
 This mainly deals with the movement ofThis mainly deals with the movement of
electrons.electrons.
 Metals have a “sea of electrons” that allows forMetals have a “sea of electrons” that allows for
quick heat transfer.quick heat transfer.

10. Heat is transferred to your bodyHeat is transferred to your body
because it is direct contact with abecause it is direct contact with a
body that is at a higherbody that is at a higher
temperature.temperature.
Imagine that you are walkingImagine that you are walking
barefoot across asphalt onbarefoot across asphalt on
scorching summer day. Whyscorching summer day. Why
do this object feels hot todo this object feels hot to
you?you?

11. {{ {{
We feelWe feel
discomfortdiscomfort
When you grabbed theWhen you grabbed the
handle of hot metal pan.handle of hot metal pan.
What would you feel?What would you feel?

12. Boiling a pot of water on theBoiling a pot of water on the
stove to cook elbow pasta.stove to cook elbow pasta.
What do you notice to the
pasta when it suddenly
drop to the boiled water?
The pasta rises to the
top of the pan gets
pushed to the side and
sink to the bottom it
rises.

13.  The cooler water at the top sinks and theThe cooler water at the top sinks and the
warmer water dense, less dense water rises towarmer water dense, less dense water rises to
the top.the top.
 As the cooler ware sinks it heats up and movesAs the cooler ware sinks it heats up and moves
back to the top.back to the top.
 There is a reversible process of hot and warmThere is a reversible process of hot and warm
water. The water being heated up and thewater. The water being heated up and the
warmer water sinks in a continuouslywarmer water sinks in a continuously
movement .movement .
How it was happen?How it was happen?

14. What is convection?What is convection?
 is the transfer ofis the transfer of
heat by theheat by the
motion of liquidsmotion of liquids
and gases.and gases.

15. What is radiation?What is radiation?
 is heat transfer by electromagneticis heat transfer by electromagnetic
waves.waves.
Is heat transfer that travels throughIs heat transfer that travels through
empty spaceempty space
It does not require a medium

16.  The heat comingThe heat coming
from the sunfrom the sun
emitted by theemitted by the
boy, that feels himboy, that feels him
warm.warm.
 ElectromagneticElectromagnetic
radiation giveradiation give
heats to the bodyheats to the body
of the Earth.of the Earth.
Sun
the heat coming from the
sun give us a temperature
or energy negligible by the
air resistance.

17. How will radiation method explain theHow will radiation method explain the
picture?picture?
Branches
preheated
by
convection
and
radiation
Brush
preheated by
radiation
Log preheated by
conduction/radiation
Duff preheated by
conduction/radiation
Tree trunk
preheated by
radiation

18.  Is the transfer of heatIs the transfer of heat
through directthrough direct
contact with thecontact with the
material.material.
 is the transfer of heatis the transfer of heat
by the motion ofby the motion of
liquids and gases.liquids and gases.
 Is the transfer of heatIs the transfer of heat
through emptythrough empty
space.space.
Radiation
Conduction
Convection

19. Convection MethodConvection Method
 Cooler temperature is denser than theCooler temperature is denser than the
warm one, that is why it cooler atwarm one, that is why it cooler at
night than in day timenight than in day time

20.  In ¼ sheet of paper explain briefly andIn ¼ sheet of paper explain briefly and
accurately the following: (5 points each)accurately the following: (5 points each)
 1. Explain the water cycle and relate it in1. Explain the water cycle and relate it in
heat transfer.heat transfer.
 2. How energy is transfer in the process of:2. How energy is transfer in the process of:
 A. ConductionA. Conduction
 B. ConvectionB. Convection
 C. RadiationC. Radiation
EssayEssay

21.  Define thermal conductivity.Define thermal conductivity.
 List some thermal conductivities ofList some thermal conductivities of
different materials.different materials.
 What are the different equations to getWhat are the different equations to get
radiation rate?radiation rate?
AssignmentAssignment

22. PREPARED BY:PREPARED BY:
KAREN A. ADELANKAREN A. ADELAN
BSE 3BSE 3 
Thank you!!!!!MabuhayThank you!!!!!Mabuhay