3 Types of Heat Transfer

Heat Transfer-

The movement of

heat from a warmer

object to a cooler

object.

1. 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.

conduction

2. Convection

Heat transfer by

means of up and

down movements

called convection

currents.

Can occur only in a

liquid or a gas

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.

3. Radiation

Heat transfer through

open space.

Occurs in a gas only.