11. 2 heat energy energy passed as heat from one object to another
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Heat Energy
Energy passed as heat from one object to another
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Heat always passes from a hotter object to a cooler object
If you hold an ice cube in your hand,
it will start to melt
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Heat energy passes from your hand to the ice cube
The heat energy makes the molecules in the ice move faster
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The ice begins to melt,or become a liquid
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Heat energy can be passed in 3 ways
1.Conduction2.
Convection3. Radiation
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Conduction
Heat passes through solids
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When one object passes heat to another by conduction,
The heat keeps flowing until both objects are equally hot
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Have you ever eaten hot soup with a metal spoon?
After a while, the spoon gets hot
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The hot soup causes the molecules in the spoon to move
faster
Heat travels from the soup up the spoon to your hand
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Convection
Heat passes through liquids and gasses in currents
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Molecules in liquids and gases move apart when they are
heated
This happens during convection
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When you heat water on the stove,
The bottom layer of water is heated first
The molecules in this layer of water move farther apart
Then floats to the top, and the cooler, heavier water on the top
falls to the bottom
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These molecules are called convection currents
In winter, convection heats the air in your house
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Radiation
Movement of heat energy in waves
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Solar heat comes in radiation waves
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Microwave ovens heat food byradiation
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Heat energy can be passed in 3 ways
1.Conduction - contact2. Convection - current3. Radiation - waves