How does a refrigerator work?
The refrigerator is one of the many miracles of the Age of Science and for it we should say a big Thank you to our clever chemists. They used what they knew about the behavior of certain chemicals to make a new substance which old Mother Nature never dreamed of making. What's more, these solid citizens did not stop when they made the first refrigerator chemical. They kept on improving it so that our wonderful refrigerators and deep freezers are getting better and better all the time.
When grandma was a girl, there was an icebox in the kitchen and melting ice was a never ending, drip dripping problem. The neat refrigerator is far, far superior to its icebox ancestor but it is harder to understand, especially since its inner workings are sealed safely away from bright and curious eyes.
Ice is cold, as everyone knows, and its coldness seems to be catching. If you hold it, your fingers become numb with cold and maybe this explains how the chunk of ice kept the old icebox cool. But actually this is not the whole story. Ice does not make a cold day any colder, it only cools things that are warmer than itself.
In warm air, the temperature of ice rises to the melting point of water. Soon the solid ice turns into wet liquid, but this process takes energy heat energy from the air. Coldness is merely absence of heat. The air near the ice loses some of its heat and becomes cooler. When alcohol turns into vapor it also steals heat, which is why we use cooling colognes.
The marvelous chemical in a modern refrigerator is turned from a liquid into a gas and then back again into a liquid.
Each time the liquid turns into gas, it steals heat from the inside of the refrigerator, leaving the food cool and turning the water in the ice trays into ices We call such a chemical a refrigerant and it is sealed in strong metal tubes so that it can travel around and around to be used again and again.
The liquid refrigerant runs through the coils around the ice trays, stealing the heat and turning into gas. As a gas, it goes on its way to the machinery of the refrigerator. There it is compressed, or squeezed to take up 'Less room, and cooled by a whirring fan. Soon the gaseous refrigerant is cool enough to turn into drops of liquid. Then it is ready for another heat stealing trip through the refrigerator.
In the world around us, warm and cool things tend to trade temperatures and reach a happy medium. On a hot day, ice steals some heat from the air to turn into warm water. It cannot turn back into solid ice unless the air drops to the freezing point of water. The liquid refrigerant in our modern refrigerator takes heat from inside the refrigerator to turn itself into gas and the gas goes to built in machinery to be turned back again into liquid.