Eli5: How is it possible that deserts are super hot at day time and below freezing point at night time?
In: Earth Science
Things stay warm if:
1. There is a lot of the object to heat up. In the desert there isn’t much stuff.
2. The object needs to take in a lot of heat energy as it heats up – the more heat it takes in the longer it takes to cool down. Dry things, particularly sand, get hot quickly without needing a lot of heat energy, so cool down quickly
3. The object can pass it’s heat to others that aren’t heated directly. The better an object does this, the further heat gets into it (this includes the heat getting deeper into the ground), and the more heat it needs to give out to cool back down again. Dry things are bad at passing heat around.
This one has a complex effect, as passing heat quickly also helps things cool down to a certain extent, however the important part of this effect is allowing the object to take in more total heat energy.
4. When the heat that they give out is trapped near them. If the air near them warms up and stays near them, they don’t cool down as quickly – like wearing a sweater traps air near your skin. Exposed areas have the warmed air move away very quickly, and additionally provide no protection from windchill.
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