Eli5: Insulated spill-proof mugs. Why are they so much better at keeping cold things cold than keeping hot things hot?
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For a start, temperature gradient. (All temps in Celsius)
Hot drinks start at just below 100 degrees. Liquids from the refrigerator are around 5 degrees.
If you’re outside on a 20 degree day, the gradient is much higher for typical hot liquids than cold ones.
Thermodynamics…. Think of the difference in temperature between hot things and cold things compared to the ambient air temperature. A cold drink is 35 degrees when it is 90 degrees out. That is 55 degrees difference. That is alot smaller of a difference than a 130 degree coffee and a 35 degree day in winter (95 degree difference). The more extreme the difference in temperature, the faster it will try to even out through heat loss. The air is losing heat to the cold drink and the hot drink is losing heat to the air.
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