Physics · DIY
Guests in an hour and the drinks are warm. How long in the fridge, how much faster is ice water, and why does the kitchen feel worse than the thermometer says?
A drink loses heat in proportion to how much hotter it is than its surroundings, so it cools fast at first and then crawls. That is why the last two degrees take longer than the first ten.
Water carries heat away far faster than still air, so an ice bath beats a fridge by a wide margin — and beats a freezer for the first stretch, because the freezer only wins once the air around the can has been chilled.
The kitchen thermometer says 26 °C and it feels far worse. Humidity is the reason: sweat cannot evaporate into air that is already loaded, so the body loses its main cooling route.
Newton cooling runs both ways. A cup of tea too hot to drink is the same curve in reverse, and the brewing tool will tell you when it lands in the drinkable band — plus what the milk does to the timing.
Newton cooling covers the can, the ice bath and the teacup; psychrometry covers the room. Change the starting temperature to whatever your kitchen actually is and the clock updates with it.