1. The problem statement, all variables and given/known data In a flame test lab, where different unknown substances are heated and the identity of the substance is determined by the color emitted, what can be some sources of error? 2. Relevant equations n/a 3. The attempt at a solution I need three sources of error, and so far I have this one: Even when cleaning the wire off thoroughly, small, residual amounts of liquid may still contaminate the wire, thus altering the shade of the color that is emitted by the heated substance. So I need two more, I considered the fact that a lot of times the appearance of color is subjective, so what one person sees or considers to be a certain color may not technically be that color, but I'm not sure if that makes sense as a source of experimental error. So I still need two more. Any tips/hints/help/advice would be greatly appreciated. Thanks!