Some metals like iron and tungsten glow when heated to extreme temperatures, and even when they reach a melted state. Yet some other metals such as aluminum do not glow at all even when heated beyond their melting point.
Is it just some specific properties of certain metals, or is it some of the elements within metals that can cause it to glow when heated?
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All metals will glow when heated. In fact **everything** glows at whatever temperature they are, and more interestingly everything glows the **same color** when heated to a specific temperature! This is how the “laser thermometers” work, they are just infrared sensors that detect the wavelength of infrared light emitted by objects and from that deduce what temperature they must be.
Most objects we encounter on a daily basis are glowing in a wavelength we can’t see with our eyes, some frequency of infrared. As objects become hotter though the frequency of light they emit increases (it is actually a range, but the peak frequency of emission increases). At around 525 degrees Celsius the emitted light begins to enter the visible range and we will begin to perceive a glow. In fact if you look on the back of a light bulb box you will see a little chart called “Color Temperature” with a sort of orange color on one end at 1000K and the other end being a blue color at 10,000K. That “K” is “Kelvin”, as in the temperature measurement. An object at 1000 Kelvin would glow that orange color, in this case that object being the incandescent filament of a light bulb.
Aluminum definitely does glow when heated to its melting point. However aluminum is also very conductive to heat so it can be prone to developing a sort of “skin” of cooler metal on its surface which would be below the temperature to visibly glow. If all the aluminum is molten though it does glow.
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