Black light
These are silver halides as AgCl and AgBr.
Silver halogenides are decomposed by light.
Bromine
A balck bird is not an element. No living thing is an element.
Bromine
Black chromate!
Bromine
it's depends on element's of black surface that element absorb the sun light and convert it to thermal energy and in the other side white surface doesn't had a much element like black surface.
For example silver bromide or chloride.
the heating element turns black because it heats up all the water xxxx I think this is likely to be because your water supply is acidic (pH less than 7). This can dissolve the element over time. Probably best to replace the kettle with one with a concealed element.
It just stays black because when you mix black with anything it just turns black
Silver nitrate is white, but light sensitive, so it turns black