Why does aluminum foil reflect heat?
Aluminium antipode is like any other candescent essence. The color of nearly all essence is light argentine because essence reflect inversely well any frequence.
Heat is the vibration of motes. The black body radiation is the generation of electromagnetic swells of tittles and motes that are cooling. The frequence of utmost photons depends on the temperature. At 300 kelvin, which is room temperature, the black body radiation is about 30 thz.
Desert snakes and real infrared cameras are suitable to see warm thoroughbred mammals in complete darkness because they descry photons at 30 thz.
Utmost surveillance cameras can only see photons around 300 thz, veritably near to red color. They need infrared LEDs to illuminate the scene.
The reason polished essence reflect electromagnetic swells is because of impedance mismatch. In deep space and in gas like earth earth atmosphere, the impedance is 377 ohm.
When the surge encounter the essence face, the impedance drop from 377 ihm down to0.1 ohm.
Any surge that encounter unforeseen changes in impedance, going up or down, is incontinently reflected.
Detail, it isn't heat directly that candescent essence reflect. It's the infrared photons at 30 thz that are reflected.
This be only when the hot object cool by converting mechanical vibration to electromagnetic swells at low frequence, nearly between radio swells and visible light.