What happens when you put boiling water into a plastic bottle? Why does it shrink and where does the plastic?

Question

Where does the plastic go to, into the water, or does it make the plastic thicker?

Answer 1

Many thermoplastic manufactured items undergo some stretching and thinning during forming processes such as blow-molding and rolling of sheet material. They retain enough shape "memory" so they contract in area and increase in thickness when heated.
This can be a desirable effect if controlled, and plastics with a strong shape memory are being developed for use in surgical implant and "smart fabric" applications. In addition to heat, some materials undergo shape reversions on exposure to light or magnetic fields. See the ref.

Answer 2

COME ON...

This is one of those experiments that you HAVE to try. Besides it is an easy one too. Take a coke bottle and boil some water and pour it in. What happens next????

Good Luck