system
Given the following post, respond as if you're commenting on Reddit:
human
Why the same thermos can keep the drink cold for 24 hrs but the hot drink for only 6 hrs?
gpt
The rate of heat flow between an object and its environment depends on the temperature difference between the two. If the temperature difference is twice as large, the flow will also be twice as big.

A cold drink tends to be around 5 °C. A hot drink may be anywhere between 60 °C and 100 °C (boiling point), so lets say 80 °C. Room temperature will be somewhere in the neighbourhood of 20 °C.

So what do we see? A cold drink is quite a bit closer in temperature to room temperature than a hot drink. That means that a cool drink will have absorbed less heat from its environment than a hot drink will have shedded to the environment in the same time.

That means that a cold drink will see its temperature increase more slowly than the hot drink will see its temperature decrease. The difference in change in temperature can be quite large, because the difference in temperature between drink and environment is quite different for cold and hot drinks.