If I put something in the fridge that’s 30°C, does it get colder faster than something I put in at 15°C, over a 20 minute period?

Question

If I put something in the fridge that’s 30°C, does it get colder faster than something I put in at 15°C, over a 20 minute period?

In: Physics

Answer 1

It depends, but the surprising answer is for liquids, Yes, probably.

Hot water will freeze faster than cold water when cooled.

The basic reason is because heat causes liquids to to move around in a process called “convection” (the same reason hot air rises and cold air sinks, but now imagine that rising and sinking occurring in a circuit and constantly moving around and around). This convection essentially keeps the heat on “outside” of the water and makes it easier to to cool down.