Self-Heating and Self-Cooling Cans

Self-Heating and Self-Cooling Cans
During World War II (1939-1945), some food cans had wicks on them, like candles have. The wicks were attached to an inside tube. When soldiers lit the wick, the tube heated the food.

Self heating cans actually started around 1900 for the use by mountaineers and explorers.

Newer self heating cans are easier to use. Just push a button. The button breaks a seal inside a heating cone.

Water and limestone combine in the cone, releasing heat. Three minutes later your food or drink is hot.

Self-cooling cans were harder to develop. They came along about fifty years after the self heating kind.

Astronaut were the first to use them in 1998. In one model, water evaporates inside a compartment in the can.

The evaporating water draws heat from the beverages. In two to three minutes, the drink is chilled.
Self-Heating and Self-Cooling Cans