30 points

in class we are doing a shrinky plastic lab, does it matter how long you hold the special plastic over the flame?

Usually with shrink plastic if you only let it shrink for a little bit it will curl up and won't fully shrink, but if you let it shrink for longer it will flatten out and shrink for a final time. Shrink plastic doesn't burn or melt easily either, so just let it go until it is decently flat.