2. Heat Transfer-
The movement of
heat from a warmer
object to a cooler
object.
3. 1. Radiation
Heat transfer through
open space.
Occurs in a gas only.
4. 2. Conduction
Heat transfer by direct
contact of molecules.
In other words, when one
molecule runs into
another and it runs into
another, etc.
It can occur in a solid,
liquid or a gas.
Occurs best in a solid
because the molecules
are close together.
6. 3. Convection
Heat transfer by
means of up and
down movements
called convection
currents.
Can occur only in a
liquid or a gas
7. Convection currents
Heated molecules do 2
things:
1. they expand, become
less and then..
2. they rise.
Cooled molecules do the
exact opposite:
1. they contract, become
more dense and then…
2. they sink
That is what makes a hot air
balloon rise.
