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Heating and cooling curves
17/05/2016 Cooling off
©cgrahamphysics.com 2016
Where is the best place to cool off? Antarctica
Yakutsk, Russia
North Ice, Greenland
Yukon, Canada 17/05/2016 ©cgrahamphysics.com 2016
Where is the best place to warm up?
Death Valley, California
TIRAT ZVI, ISRAEL
DEHLORAN, IRAN
OODNADATTA, AUSTRALIA
17/05/2016 ©cgrahamphysics.com 2016
Starter
• State what is meant by heat.
• State what is meant by temperature
• Does heating always result in a rise in temperature? If not, why not?
17/05/2016 ©cgrahamphysics.com 2016
Aim • Describe the difference between heat and temperature.
• Know what energy changes are taking place during changes of state.
• Investigate and record a cooling curve.
• Describe and understand heating and cooling curves.
Key words
• Heat 열
• Temperature 온도
• Energy 에너지,
• State change 상태 변화
17/05/2016 ©cgrahamphysics.com 2016
The bigger picture Have you ever wondered
Which has more heat?
450𝐶
Which has more temperature?
17/05/2016 ©cgrahamphysics.com 2016
Definition
• Heat is the transfer of energy from one object to another. It is the total energy the particles in a substance have
• Temperature is a measure of how much heat energy something has. It is the average kinetic energy of the particles in the substance.
17/05/2016 ©cgrahamphysics.com 2016
What happens to the particles?
• Melting
• Freezing
• Boiling
• Condensing
• A) what state is it occurring? (i.e. solid to gas)
• B) what happens to the amount of energy the particles have? Increasing, decreasing
• C) What is happening to the attractive forces pulling the particles together? Getting stronger, getting weaker
17/05/2016 ©cgrahamphysics.com 2016
Changing state • Take the temperature of ice melting until water
starts boiling every 30 second.
• Watch the temperature carefully.
17/05/2016 ©cgrahamphysics.com 2016
Reading No. Temperature / C 1 20 2 21 3 22 4 23 5 25 6 25 7 25 8 25 9 25
10 25 11 28 12 31 13 34 14 37 15 41 16 45 17 49 18 53 19 57 20 61
Reading No. Temperature / C 21 65 22 69 23 73 24 77 25 81 26 85 27 89 28 89 29 89 30 89 31 89 32 93 33 98 34 103 35 108 36 113 37 118 38 123 39 128
17/05/2016 ©cgrahamphysics.com 2016
5 10 15 20 25 30 35 40
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Tem
pera
ture
/ °
C
Heating a Solid
Reading
Number
17/05/2016 ©cgrahamphysics.com 2016
5 10 15 20 25 30 35 40
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Tem
pera
ture
/ °
C
Heating a Solid
Reading
Number
0
20
40
60
80
100
120
140
0 10 20 30 40 50 60 70
Tem
pera
ture
/ C
Reading Number
Heating a Solid
17/05/2016 ©cgrahamphysics.com 2016
Results
a) Where on your graph does temperature increase
smoothly each minute? (3 places)
b) What is the substance doing when there is no
change in temperature?
c) Where does the inputted heat energy go when the
temperature doesn’t increase?
17/05/2016 ©cgrahamphysics.com 2016
1.To get a material to change state requires heat
energy.
2.When we heat ice, the temperature of the ice doesn’t
change while its melting, even though we’re still
supplying heat.
3.The energy goes to breaking bonds between atoms,
allowing them the move with more freedom!
Time
4.This can be seen in a
graph when we heat
a material and record
its temperature:
Heating and State Changes
17/05/2016 ©cgrahamphysics.com 2016
Plenary: Fill in the blanks • When a heated solid turns into a _____the bonds of the
solid are been______. This requires _____and as such is keeping the temperature _____than you would expect.
• eg. Flat line despite continuous heating. Similarly...
• When a liquid goes to a _____the bonds of the solid are been_____. This ______energy and as such is keeping the substance temperature ______than you would expect.
• eg. Flat line despite continuous cooling.
LIQUID
BROKEN ENERGY
LOWER
SOLID
MADE RELEASES
HIGHER
17/05/2016 ©cgrahamphysics.com 2016
Plenary: MWB • Using simple particles drawings:
• Draw the structure of a piece of ice in a beaker.
• Draw the structure of water in the beaker.
• Have the water molecules gained or lost energy as the ice melted?
• Draw a simple heating curve showing temperature against time over the period that some ice is being melted and then boiled. Label the melting and boiling points.
17/05/2016 ©cgrahamphysics.com 2016
Key words
• Heat - the transfer of energy from one object to another. It is the total energy the particles in a substance have
• Temperature - a measure of how much heat energy something has. It is the average kinetic energy of the particles in the substance
• Energy - given to a substance in form of thermal energy or power over time
• State change - a substance changes between the three states of matter, solid, liquid and gas
17/05/2016 ©cgrahamphysics.com 2016
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