Do Now!

Can you continue with the questions

you were doing last lesson

(Expansion)?

Today’s lesson

• Describe qualitatively the thermal expansion of solids, liquids and gases

• Identify and explain some of the everyday applications and consequences of thermal expansion

• Describe qualitatively the effect of a change of temperature on the volume of a gas at constant pressure

Gather round!

Expansion

• Many substances expand when heated

• When heated, the particles (atoms or molecules) in a substance vibrate more

• This means they need more space

• So the substance expands

Heat

Important note!

The particles in a substance do not expand themselves!

Heat

Particles are the same size

Contraction

• The opposite happens when most substances are cooled

• The particles vibrate less

• They need less room

• The substance contracts

Cools

Solids

• The expansion of solids is small but strong!

Like me!

Expansion in solids

This means that we sometimes have to take into account expansion

Expansion in solidsThis means that we sometimes have to take into account expansion

Contraction can also be a problem

Liquids

• Most liquids expand when heated

Gases

• Gases expand a lot when heated!

• http://www.youtube.com/watch?v=A843PL6Yejs&feature=related

• http://www.youtube.com/watch?v=ZgTTUuJZAFs&feature=related

Let’s try an expanding worksheet!

Temperature and volume of a gas at constant pressure

• http://phet.colorado.edu/en/simulation/gas-properties

Temperature and volume of a gas at constant pressure

• When a gas is heated (at constant pressure), the gas expands.

• Can you copy this please?

HOMEWORK

• Due Thursday 22nd March

• Finish Expansion, Evaporation and Gas pressure sheets