Have you ever grabbed Have you ever grabbed the handle of a hot metal the handle of a hot metal pan? What did you feel?pan? What did you feel?

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

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

Heat TransferHeat Transfer The transfer of thermal energy between The transfer of thermal energy between

substances due to difference in their substances due to difference in their temperature.temperature.

HeatHeat is thermal energy that it is transmit is thermal energy that it is transmit from warmer object to the cooler matterfrom warmer object to the cooler matter

Heat hot to cold

ConductionConductionConvection Convection RadiationRadiation

Method of Heat Method of Heat TransferTransfer

What is conduction?

Is the transfer of heat through a material by direct contact.

Prepare a coffee in same volume of hot 40ml water Prepare a coffee in same volume of hot 40ml water at 70at 70ºC after 2 mins. measure the temperature of ºC after 2 mins. measure the temperature of the coffee using thermometer. Observe what the coffee using thermometer. Observe what happen?happen?

Prepare a coffeePrepare a coffee

Group 1 Group 2 Group 3

Styrofoam cup

Metal glass

Fiber glass

Thermal Conductivity The thermal conductivity of a material

describes how well the material conducts heat.

Styrofoam cup Metal glassFiber glass

Conductors and Conductors and InsulatorsInsulators

Conductors — Materials that allow — Materials that allow heat to quickly pass throughout the heat to quickly pass throughout the material (such as metals).material (such as metals).

Insulators — Materials that do not — Materials that do not allow heat to quickly pass throughout allow heat to quickly pass throughout a material (such as wood or plastic).a material (such as wood or plastic). This mainly deals with the movement of This mainly deals with the movement of

electrons.electrons. Metals have a “sea of electrons” that Metals have a “sea of electrons” that

allows for quick heat transfer.allows for quick heat transfer.

Heat is transferred to your Heat is transferred to your body because it is direct body because it is direct contact with a body that is contact with a body that is at a higher temperature. at a higher temperature.

Imagine that you are Imagine that you are walking barefoot across walking barefoot across asphalt on scorching asphalt on scorching summer day. Why do summer day. Why do this object feels hot to this object feels hot to you?you?

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We feel We feel discomfordiscomfort t

When you grabbed the When you grabbed the handle of hot metal handle of hot metal pan. What would you pan. What would you feel?feel?

Boiling a pot of water on Boiling a pot of water on the stove to cook elbow the stove to cook elbow pasta.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.

The cooler water at the top sinks and The cooler water at the top sinks and the warmer water dense, less dense the warmer water dense, less dense water rises to the top.water rises to the top.

As the cooler ware sinks it heats up As the cooler ware sinks it heats up and moves back to the top.and moves back to the top.

There is a reversible process of hot There is a reversible process of hot and warm water. The water being and warm water. The water being heated up and the warmer water sinks heated up and the warmer water sinks in a continuously movement . in a continuously movement .

How it was happen?How it was happen?

What is convection?What is convection?

is the transfer is the transfer of heat by the of heat by the motion of motion of liquids and liquids and gases.gases.

What is radiation?What is radiation? is heat transfer by is heat transfer by electromagnetic waves.electromagnetic waves.

Is heat transfer that travels Is heat transfer that travels through empty spacethrough empty space

It does not require a medium

The heat coming The heat coming from the sun from the sun emitted by the emitted by the boy, that feels him boy, that feels him warm.warm.

Electromagnetic Electromagnetic radiation give radiation give heats to the body heats 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.

How will radiation method explain How will radiation method explain the picture?the 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

Is the transfer of Is the transfer of heat through heat through direct contact direct contact with the material.with the material.

is the transfer of is the transfer of heat by the heat by the motion of liquids motion of liquids and gases.and gases.

Is the transfer of Is the transfer of heat through heat through empty space.empty space.

Radiation

Conduction

Convection

Convection Method Convection Method

Cooler temperature is denser Cooler temperature is denser than the warm one, that is why than the warm one, that is why it cooler at night than in day it cooler at night than in day timetime

In ¼ sheet of paper explain briefly and In 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 1. Explain the water cycle and relate it in heat transfer.in heat transfer.

2. How energy is transfer in the process 2. How energy is transfer in the process of:of:

A. ConductionA. Conduction B. Convection B. Convection C. RadiationC. Radiation

Essay Essay

Define thermal conductivity.Define thermal conductivity.List some thermal List some thermal conductivities of different conductivities of different materials.materials.

What are the different What are the different equations to get radiation rate?equations to get radiation rate?

Assignment Assignment

PREPARED BY: PREPARED BY:

KAREN A. ADELANKAREN A. ADELAN

BSE 3 BSE 3 Thank you!!!!!Thank you!!!!!MabuhayMabuhay