I was thinking about this one, and I think it was one of my favourite experiments at school…. or at least one that I really remember doing!
If you add oxygen to magnesium in its pure form, i’m not sure if anything happens. But if you heat up the magnesium and THEN add oxygen by letting the air get to it, then this is called oxidation and the magnesium glows bright white!
I remember that experiement as my friend forgot to put the magnesium in the crucible to be heated up, and couldn’t work out why hers didnt glow! It was because she had forgotten to put it in! Oh no!