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I've thought of trying this before with a toy sterling engine and a tinfoiled satellite dish. You can make ice that way when the air temp is up to 9 or 10 celci
by inflatableDodo 7y ago
I've thought of trying this before with a toy sterling engine and a tinfoiled satellite dish. You can make ice that way when the air temp is up to 9 or 10 celcius if you put a shot glass of water in polystyrene foam with an opening at the focal point of the dish.
- TheSpiceIsLife 7y agoWait what? Wouldn’t the infrared reflectivity of the parabola concentrate heat energy in to the focal point?
- inflatableDodo 7y agoYou point it at an empty patch of sky. edit - have a go at pointing an infrared thermometer at an empty patch of sky on a clear night.
- TheSpiceIsLife 7y agoOh, right, I understand now, thanks.
- inflatableDodo 7y agoI love radiative cooling. When you first realise what the hell is going on, it is one of those 'aha' moments of real deeper appreciation of a subject.
- duckymcduckface 7y agoMy favorite demo is an electric stoves, turn it on and stare at it from a point along the plane that it's on and you start to marvel at how much heat can be transferred by radiation.
- TheSpiceIsLife 7y agoIsn’t that convection? The air coming in to contact with the hot surface rapidly heats and rises and cooler air rushed in to replace it. I thought that’s what we saw as per your instructions? I thought air (mostly nitrogen and oxygen) is mostly transparent to infrared radiation?
- im3w1l 7y agoOne way to think about it is that the tinfoil will block incoming radiation🞻, while allowing outgoing radiation. 🞻 From the local surroundings. It will amplify the incoming radiation form space but that doesn't matter as space is cold.