Do now!Can you sit down quickly and quietly?

Books

• Write a title please – It’s year 8, sometimes you have to figure out the title yourself!

Books

• Underline titles!

Books

• If Mr Porter writes “can you finish this please”…..finish it!

Books

• Continue the next piece of work immediately after the previous – no blank spaces please!

Books

• Use the target sheets to revise

Books

• Neatness!

Spelling!

Cooling

What did you do?

Why do you think Mr Porter is using this picture?

Cooling curve

In the experiment, you will have noticed that the temperature of the wax stopped changing as the waxchanged from a liquid to a solid.

Temp (°C)

Time (mins)

Melting point

Cooling curve

This always happens during a change of state

Temp (°C)

Time (mins)

Melting point

Cooling curve

Why does

this happen?

Latent heat

When the molecules of a substance settle into the regular pattern of a solid, energy is released as bonds are formed. This energy released is called latent heat. This stops the temperature from falling.

Energy released

(“latent” = “hidden”)

Latent heat

The opposite happens when a solid melts. Heat is needed to break the bonds between the solid particles (instead of raising the temperature)

Temp (°C)

Time (mins)

Melting point

solid

liquid

Energy absorbed

Melting ice

Heat energy is needed for converting ice at 0ºC to water at 0ºC

This heat energy is needed to melt the ice, NOT make it hotter

0°C

0°C

Freezing water

Heat energy is released when water at 0ºC is converted to ice at 0ºC

This heat is keeps the temperature constant whilst the water is freezing.

0°C0°C

Evaporating water

Heat energy is absorbed by the water when changing to a gas, keeping the temperature constant.

100°C100°C

Got it?

Can you read pages 114 and 115 of your book?

In silence please

Can you read pages 114 and 115 of your book?

Can you answer the questions on the

pages?

Just time for a quick dog accident

50 kg

Ooops!

50 kg