Why is it that if we wet our fingers before putting out a candle, we don’t get burned, but if we grab a hot pan out of the oven with a wet oven mitt, we get burned?
In: Physics
the candle side seems to have been covered pretty well at least. As for the oven mitt, think of snowboarders. Most of them, rather than wear one big puffy coat, will wear multiple layers of thinner material. That’s because the trapped air between layers is itself actually a really good insulator, meaning it takes a while to change temperature, so it’s a good material to keep a hot space hot, or a cold space cold.
Actually, they tried to use this principle for houses too, by making air filled walls sealed in plastic sheets. It worked great for temperature, but eventually some really toxic mold grew in the air pockets, so it didn’t take off.
But yeah, your hot pad is made (usually) of something with air trapped in it. Because it takes so long for that trapped air to get warmer, you have time to do what you’re doing with the really hot thing, then put it back down before a dangerous amount of heat reaches your hand. But the water is a much better conductor… it gets hot or cold really fast and then spreads that temperature on to the next thing. So if you’re out in the snow and sweat through your wool jacket, now you’re also in tons of danger because your body heat gets out through the damp stuff way way faster than before. Same concept with the oven mitt getting wet, and transferring heat.
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