Why is it that warm food/drinks get cold when left out but cold food/drinks get warm when left out?


Why is it that warm food/drinks get cold when left out but cold food/drinks get warm when left out?

In: Physics

It’s all about relative temperatures. Two things will tend to balance their temperatures, so hot stuff will cool down in cooler air, and cold stuff will heat up in hotter air (relative to each thing being left outside)

The same principle applies as to snow melting and (the air is warmer than the snow) or water freezing (the air is cooler than the water)

They do not produce heat of their own, so they equilibrate with the temperature of their surroundings by either giving away or absorbing heat until they are the same temperature as the room.

Cold food is below room temperature and hot food is above. In reality, both just get closer to room temperature.

Because room temperature is usually cooler than hot food and warmer than cold food. The temperature will always trend towards room temperature, so unless it’s a freezing cold day, cold food will warm over time. And most hot food is served in like the 140-ish range (Fahrenheit) which is way hotter than its ever gonna be, so hot food will trend down.

Basically everything moves toward room temperature, food or otherwise.

It so happens that we like some food to be hot so we heat it, and some to be cold so we chill it, and that wears off after a while. Your potato chips, from the cabinet, which have neither been heated nor chilled, stay exactly as they are because they are already at room temperature.

Heat is really just movement. when something is hot, it’s molecules are moving (or vibrating if it’s solid) faster than something that is colder. When a hot things touches a cold things, it “bumps” colder thing making it move faster but slowing it down in the process.

What this adds up to is whenever a hot thing is near a cold thing, the hot thing will get colder and the cold thing hotter until they reach the same temperature. For drink of food, the hotter or colder thing is the air and other stuff around it, and there is a lot of air, so it doesn’t really change the change of temperature if it that much because there is so much of it. The food is much smaller, so it loses or gains that heat much more obviously.

For those more informed, I am not covering radiant heat here, but I don’t consider that necessary for a basic understanding.

Typical room temp is 70 degrees. A cold drink is colder than 70 and a hot drink is warmer than 70. As they are exposed to room temp they will keep exchanging energy until equilibrium temp is met