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
A thin layer of water can *very* briefly protect you from hot temperatures by absorbing the energy and evaporating before the heat transfer reaches your skin. For an object with very little residual heat like a candle wick, this is sufficient.
A much more massive metal pan has vastly more heat to give, and the large volume of water only serves to conduct it to your hands more efficiently.
Your mistaking thermal energy and heat.
A flame may be very HOT but only a thin layer of gas on the outside of the flame is generating that heat. Reduce the heat of those gas particles and the flame goes out, and because the liquid on your fingers has a much higher heat capacity than the gas, you don’t feel the burn.
A hot pan may not be as HOT, but the thermal energy is way bigger. You have a fuck ton of particles through the entire metal pan that are hot and will give off their heat very easily. The layer of water that could absorb the heat soaks it all up, and now the rest of the water in the towel has no where to evaporate into so it keeps spreading the heat, eventually to your hand.
A dry cloth is safe again because the thermal capacity. It doesn’t transfer heat very well, so you could also use that to put out an candle at the risk of getting it dirty OR putting it in contact with something hot enough to light it on fire (another property of heat)
Imagine you take a few ounces of water to put out the flame of a candle. It will extinguish it right away. The water will still be cold because not much heat energy was stored in the wick.
Now imagine a cast iron pan heated to 400 degree. Toss the water in the pan or dip the handle in the water for 5 seconds. The water will flash boil. If you put your face near the steam that rises you might even burn your skin.
When your oven mitt is wet, the water it contains will steam out hotter than boiling water and burn your hand very quickly.
Candle = small heat.
Hot pan = big heat.
Small heat smaller than wet fingers.
Big heat bigger than wet oven mitt.
Fire needs oxygen, hot metal doesn’t. Fire don’t burn long if you pinch it fast enough. And by not for long I mean you’ll hear a *tsss* sound.
You’ll get the same sound with a pan, but thats you’re skin frying not the water sizzling.
This dude wants to know why you can’t just blow out a bonfire but you can a birthday candle
Because the heat stored energy in the pan is magnitudes greater than that in a candle, and the conductivity of metal is vastly greater than a wick.
This is a scale and mass issue.
The candle wick has a relatively small mass, so the small amount of water on your fingers absorbs almost all of the heat energy without much turning to steam, and a layer around your finger stays below 100C.
The pan has a relatively large mass, so it can transfer a large amount of heat energy into your wet oven mitt. The water absorbs enough to turn into steam, which then expands to fill the space around your dry hand. That steam then imparts all of that heat energy to your hand before condensing back into water, which burns you.
TLDR: Specific heat of transformation is a bitch.
If you take an iron pan out of the oven and throw water on it, it will immediately will turn to steam. FWOSSH! The same thing happens when you put a damp mitt on it. The water in contact with the metal will turn to steam very quickly and hit your fingers super hot. It depends on the ratio of the metal type, how hot it is and how much water the mitt is holding. If you have a lot of water and low heat, you are fine as the water can take it without turning too hot or even flash into steam. But if you have lots of heat and low water, the water will be “overwhelmed” and burn you.
Oh dude. I was drunk and stoned a few weekends ago and grabbed a red hot cast iron pan with my bare fucking hand. The skin is still peeling off
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