Heat transfer in 3 ways are conduction, convection and radiation.

Heat transfer in 3 ways are conduction, convection and radiation.

1. 3 Types of Heat Transfer3 Types of Heat Transfer

2. Heat Transfer-Heat Transfer-

The movement of The movement of
heat from a warmer heat from a warmer
object to a cooler object to a cooler
object.object.

3. 1. Conduction1. Conduction

Heat transfer by direct Heat transfer by direct
contact of molecules.contact of molecules.

In other words, when one In other words, when one
molecule runs into molecule runs into
another and it runs into another and it runs into
another, etc.another, etc.

It can occur in a solid, It can occur in a solid,
liquid or a gas.liquid or a gas.

Occurs best in a solid Occurs best in a solid
because the molecules because the molecules
are close together.are close together.

4. conductionconduction

5. 2. Convection2. Convection

Heat transfer by Heat transfer by
means of up and means of up and
down movements down movements
called convection called convection
currents.currents.

Can occur only in a Can occur only in a
liquid or a gasliquid or a gas

6. Convection currentsConvection currents

Heated molecules do 2 Heated molecules do 2
things:things:
1. they expand, become 1. they expand, become
less and then..less and then..
2. they rise.2. they rise.
Cooled molecules do the Cooled molecules do the
exact opposite:exact opposite:
1. they contract, become 1. they contract, become
more dense and then…more dense and then…
2. they sink2. they sink
That is what makes a hot air That is what makes a hot air
balloon rise.balloon rise.

7. 3. Radiation3. Radiation

Heat transfer through Heat transfer through
open space.open space.

Occurs in a gas only.Occurs in a gas only.