Question: When I Put A Flame To Magnesium Strip Why Is It Bright White?

Ailsa Powell answered on 23 Jun 2011:

This is because of the emission spectrum of different elements.
When you give an element energy – in this case heat – the electrons jump up to a higher electron shell, when they fall back to a lower electron shell the emit the energy and that is often seen as a coloured light. In the case of magnesium you are seeing bright white, if you tried it with calcium you would see brick red, iron would be gold etc. It’s a useful and quick way to identify elements.