This is an old one the answer is "the Weather"
I turn polar bears white (When the sun is up you can see that they are white)
I make guys have to pee ( well i hae to go when i get really cold due to the fact that as the temperature lowers the amount of urine per minute gathered increases by 25 to 50 percent)
and girls comb their hair (the heat causes split ends in the hair and makes it go up and be sticky etc theirfore you must brush it back down)
I make celebrities look stupid ( rain and wind)
and normal people look like celebrities ( ie the rain and wind again ie maralyn monroe with the wind blowing up her skirt when doing photo shoots you generally use the weather and different lighting to get the correct picture results)
i turn pancakes brown ( heat)
and make your champane bubble ( due to the results of correct temperature durring fermentation)
If you squeeze me, i'll pop ( when squeezing a fire the fire goes out due to lack of oxygen therefore the fire goes out when squeezing)
If you look at me, you'll pop ( fire extreme heat)
Hmm i'm probably wrong but i might not be, then again i'm a hardvard student so there's only a 3% chance of my success lol