[krismast]

Well I tried to burn fire with different colors. I got the info here: http://chemistry.about.com/cs/howtos/a/aa052703a.htm. I put Potassium Chloride into Isopropyl Alcohol and then lit it. But it doesn't really work. It just looks like normal flames.

[agrobert]

Try using an aerosol pump to spray the solution into a flame.  Also observing color changes is done best in a dark room so that you can differentiate between the desired color and the regular flame color.

[UnintentionalChaos]

Potassium's color is immensely weak. Even traces of sodium will contaminate it and make it yellow (Plus KCl does not really dissolve in alcohol well, nor does it vaporize enough to get carried into the flame). You want to test it with a blue flame from propane or some kind of gas. To see potassium's color, you should heat some KCl in a spoon or something and blow a propane torch across it. You could also make pyrotechnics that generate a flame and use potassium nitrate or potassium chlorate/perchlorate as an oxidizer. The only one I have tried that colors alcohol or wood fires remotely well is copper chloride (I have not done lithium or strontium, but they should work too) and it only gets some color mixed into the regular flames. You can get some nice colors in methanol and ethanol with boric acid due to formation of esters. Woelen's site has info on this: http://81.207.88.128/science/chem/exps/borate_ester/index.html