Refrigeration

Refrigeration means making things cold on purpose. Cold food does not spoil as fast as warm food. Before fridges were invented, people had to salt, dry, or smoke their food to keep it. Today, almost every kitchen has a refrigerator to keep food fresh.

How a Fridge Works

A fridge uses a special liquid that moves through tubes inside it. The liquid takes heat from inside the fridge and carries it outside. This is why the back of a fridge feels warm. As heat leaves, the inside gets cold and keeps the food chilled.

A Big Change for Food

Long ago, people cut ice from frozen lakes and put it in boxes to keep food cold. The first electric home refrigerators were sold in the early 1900s. Refrigeration also lets trucks and ships carry food across long distances. People can now eat fresh fruit even when it is winter outside.

Fun Facts

• Ice cream became popular after refrigeration was invented.
• Some old homes had rooms called iceboxes instead of fridges.
• Freezers are just very cold refrigerators.

Did You Know?

Before fridges, ice was such big business that ships sailed with huge blocks of ice all the way from cold countries to hot ones.