Energy Transfer by heating

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  • Created by: Dechante
  • Created on: 07-05-17 14:52
What is infrared radiation?
Infrared radiation is energy transfer by electromagnetic waves. All objects emit infrared radiation. The hotter an object is, the more infrared radiation it emits in a given time.
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What does emit mean?
Emit means to give out
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What is the greenhouse effect?
The Earth's atmosphere acts like a greenhouse made of glass. Gases in the atmosphere, such as water vapour, methan and carbon dioxide, trap infrared radiation from the Earth. This makes the Earth warmer than it would be if it had no atmosphere.
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What surfaces are the best emitters?
Dark, matt surfaces emit more infrared radiation than light, shiny surfaces.
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Which surfaces are the best absorbers?
Dark, matt surfaces absorb more infrared radiation than light, shiny surfaces.
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Which surfaces are the best reflectors?
Light, shiny surfaces reflect more infrared radiation than dark, matt surfaces.
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What is the kinetic theory of a solid?
The particles in a solid are held next to each other in fixed positions. It also has a much higher density than gas.
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What is the kinetic theory of a liquid?
The particles in a liquid move about at random and are in contact with each other.
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What is the kinetic theory of a gas?
The particles in a gas move about random and are much further apart than particles in a solid or liquid.
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What is evaporation?
Evaporation is when a liquid turns into a gas because of a increase in heat. Cooling by evaporation of a liquid is due to the faster-moving molecules escaping from the liquid.
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What is condensation?
Condensation is when a gas turns into a liquid because of a decrease in heat.
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What is conduction?
This is the way that heat energy can move through a substance. Metals are the best conductors of energy. Materials such as wool are the best insulators. Non-metals are poor conductors because they do not contain free electrons.
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Why does conduction happen?
Conduction of energy in a metal is due mainly to free electrons transferring energy inside the metal.
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What do free electrons do?
They increase the rate of energy transfer.
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How do convection currents work?
Heating a liquid or a gas makes it less dense so it rises and causes circulation.
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What is convection?
Convection is the circulation of a fluid (liquid or gas) caused by heating it. Convection only takes place only in liquids and gases.
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What can convection currents be used for?
Kettles, sea breezes, hot water at home
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How can evaporation be increased?
Increasing the surface area of the liquid, increasing the liquid's temperature, or by creating a draught of air across the liquid's surface.
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How can condensation be increased?
Increasing the area of surface, reducing the temperature of surface
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What does the rate of energy transfer depend on?
1) The shape, size and type of material of the object 2) The materials the object is in contact with 3) The temperature difference between the object and its surroundings
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Other cards in this set

Card 2

Front

What does emit mean?

Back

Emit means to give out

Card 3

Front

What is the greenhouse effect?

Back

Preview of the front of card 3

Card 4

Front

What surfaces are the best emitters?

Back

Preview of the front of card 4

Card 5

Front

Which surfaces are the best absorbers?

Back

Preview of the front of card 5
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