Upload
rudolph-gallagher
View
217
Download
0
Embed Size (px)
Citation preview
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