Do now!

He’s going to blow!

Be careful

Good

Neutral

Excellent

MOODOMETER

Can you finish the sheet you started on

Friday (“Testing insulation 1”)?

A reminder

Heat can travel by Conduction

• Hot particles vibrate more, so collide with adjacent particles.

• Metals are good conductors because the atoms are close together and free electrons can carry energy too.

• Gases are poor conductors because the particles are far apart.

Heat can travel by Convection

A hot fluid expands, is less dense, so rises. Cold fluid takes its place. A convection current can be formed.

Infrared radiation

• Heat can travel by infrared radiation (“Hot light”!)

Infrared radiation

Black objects are good absorbers of infrared radiation.

Infrared radiation

Shiny objects reflect infrared radiation.

Nottingham Forest winning the champions league in 1979

Today’s lesson

Insulation!

Insulation InvestigationStick the

sheet in and read it.

Vacuum Flask (“Thermos”)

The insulated lid stops the heat escaping (and entering) by convection

The vacuum between the two walls stops the heat escaping (and entering) by conduction

vacuum

The silvered inner and outer stops the heat escaping (and entering) by radiation

silvered outer

silvered inner

This means hot liquids stay hot because the heat cannot escape

Hot chocolate

This means cold liquids stay cold because the heat cannot enter

Cold Vimto

In reality, some heat escapes via the lid and eventually the liquid inside will become the same

temperature as the surroundings

In a perfect flask without a lid, a hot drink would stay hot forever!

Hot chocolate

The vacuum flask

Can you complete the sheet please?

Questions!

Can you do the questions on

pages 106 and 107?