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.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .