How does a fridge keep food cold?

Open the fridge and a cool breath drifts out. Your milk and cheese stay fresh in there for days. But a fridge cannot really “make” cold. So what is its trick?

A fridge moves heat away

Here is the surprise: cold is just a place with less heat. To make the inside cold, a fridge does not add cold — it takes the heat out and carries it somewhere else.

Think of it like scooping warmth out of a box with an invisible spoon. The more heat the fridge scoops away, the cooler the food inside becomes.

A special liquid does the carrying

Inside the fridge runs a thin pipe filled with a special liquid. As this liquid flows through the cold part inside, it soaks up heat from your food and air, just like a sponge soaks up water.

Now warm, the liquid is pumped to the back of the fridge. There it lets all that heat go into the room. (That is why the back of a fridge feels warm — feel it gently sometime!)

Then the liquid flows back inside, cool again, ready to soak up more. Round and round it goes, all day and night.

A never-ending loop

This heat-carrying loop never stops while the fridge is plugged in. Scoop heat from inside, dump it out the back, repeat — and your food stays nicely cold.

Wonder fact: Your fridge gently warms your kitchen! All the heat it takes out of the food has to go somewhere — into the room.