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AstronomyAnswerBook: Energy

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1. Energy ... 2. Energy Transport

This page answers questions about energy. The questions are:

1. Energy

Energy is the ability to do things. The more energy something has, the further it can go or the faster it can go or the greater the influence is that it can have. There are many different kinds of energy. A few of them are listed below.


2. Energy Transport

There are three ways in which you can transport energy:

  1. by convection, in which temperature differences make hotter material move to colder areas and colder material to hotter areas, which means that there is net heat (and so energy) transport from hot to cold areas. The energy moves at the speed of the material.
  2. by conduction, in which heat travels through a material without making the material itself move. The energy moves at a speed that depends on the characteristics of the material.
  3. by radiation, in which energy travels through empty space (for example, as electromagnetic radiation such as light). The energy moves at the speed of light.

All three kinds of energy transport happen when you heat a pan of soup on a fire. The hot gases from the fire go up because of convection. The fire produces heat radiation, which you can block with your hand. The outside bottom of the pan is heated and conduction makes the heat reach the inside bottom of the pan, where it heats the soup. At first, the heat travels up the soup only by conduction, but later (when the soup is boiling) also by conduction.


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Last updated: 2016−02−07