It just kind of feels warm
In: Physics
Where the hell does a 900F oven exist? That’s a kiln, not an oven.
It causes pain on my oven that only goes up to 230c so an oven twice that temperature could certainly burn you.
Air is a relatively poor medium for transferring heat. Direct contact with metal, or submerging in water or something would be much quicker. That is what will burn in the short term, high heat over a short time.
Since air doesn’t transfer heat to our face very quickly, it doesn’t burn us much. Given enough time it certainly would, but a few moments will just be uncomfortable.
Air is a poor conductor of heat. I wouldn’t recommend it, but you can stick your hand into a 120 C oven for a few seconds and be totally fine whereas putting your hand into 100 C (boiling) water would cause serious injury. Water is a much better conductor of heat.
Conductivity is basically just a measure of how quickly one object can transfer heat to another.
An example on the cold end: dry ice is really really cold (-78 C) but can be handled briefly with nitrile exam gloves without causing any damage or even any significant discomfort.
When you open the oven door a relatively small amount of very hot air diffuses quite quickly into a large amount of significantly cooler air. Thus the temperature even a short distance away from the oven door will be much cooler.
Unless the oven is airtight, the hot air doesn’t “rush” out of it when it’s opened, because the pressure inside and out is the same. The heat you experience is from slight mixing of the air, plus infrared radiation from the hot surfaces. At no point are you blasted with 500°C air (which would definitely hurt you).
Air doesn’t hold much energy in the form of heat. It heats up and cools down very quickly. It also doesn’t conduct heat very well; air makes an excellent insulator, especially if you can keep it still (this is why foam and down make good insulation, they hold air still).
So when you open the oven door, the puff of hot air that comes out is cooling down quickly, and what heat it does have does not travel easily from the air into your skin. The combination of those two things keep you from getting burned due to brief exposure to hot air.
Because it’s dry air, probably also diluted by ambient air.
On the other hand, if you’ve got something in your oven at 250°C that’s a little moist, so that the air is laden with water vapor, it’s like being punched by a lava fist if you get that in your face.
Air takes a long time to burn anything. It also doesn’t rush out very readily, if anything cold air is more likely to rush in due to the pressure difference.
Now if you had some sort of fan blasting the hot air towards you, then yeah you’d get burned pretty quickly, that’s basically how a convection oven or air fryer cooks food so quickly
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