How Refrigerators Work

A refrigerator does not actually make cold. It moves heat from inside the fridge to the outside. If you feel the back or bottom of a refrigerator, it is warm. That warmth is the heat that was removed from inside. A special liquid called refrigerant circulates through the system to carry the heat out.

The Cooling Cycle

A refrigerant flows through tubes inside the fridge. Inside the fridge, the refrigerant evaporates and absorbs heat from the food and air. The gas is then pumped to coils on the outside of the fridge. There, the gas is compressed back into a liquid and releases the heat. The cycle repeats over and over.

Why Cold Keeps Food Fresh

Cold temperatures slow down the growth of bacteria and mold that spoil food. At refrigerator temperatures of about 35 to 38 degrees Fahrenheit, bacteria grow much more slowly. In the freezer at 0 degrees, bacteria stop growing almost completely. This is why refrigerated food lasts much longer than food left out.

Fun Facts

• Before refrigerators, people kept food cold by storing it in ice houses or underground cellars.
• The first home refrigerator was sold in 1913 and cost about twice as much as a car.
• Opening the fridge door accounts for about 7 percent of the energy the fridge uses.

Did You Know?

Before electric refrigerators were common, an iceman would deliver large blocks of ice to homes. Families placed the ice in an insulated icebox to keep their food cold. The ice would slowly melt and had to be replaced every few days!