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Heat |
Heat is the flow of energy from one material to another. Heat moves from warmer objects to cooler objects. An insulator is a material that does not transfer heat very well such as a blanket. A conductor is a material that transfers heat quickly such as a frying pan. The pan transfers heat from a burner to the food.
Temperature is a measure of how hot or cold something is. A thermometer measures temperature. Fahrenheit and Celsius scales measure temperature.
Conduction is the transfer of heat by contact of two material objects. An example of conduction is heat transferred from the coils to the metal pot. Convection is heat that is transferred by the flow of liquid or gas. An example is heating water in a pot. Radiation is the transfer of heat through space. An example is heat from the Sun reaching the Earth by radiation.
Matter that expands gets larger when it is heated. Matter that contracts, gets cool or shrinks. When an air balloon is heated, it expands. The air particles bounce off each other with more energy, and take up more space.
The two sources of heat on Earth are the Sun and the burning of fossil fuels. The Sun is a hot ball of gases. Fossil fuels formed long ago from the remains of plants and animals. Fossil fuels are coal, oil, and natural gas. Fossil fuels are nonrenewable resources because once they are used up, they are gone forever.
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