ice.
next, pour 1/2 cup of boiling water into the 2 liter bottle. after the water is in the bottle, wait for 2 minutes.
after two minutes have passes, put the lid back on the bottle. make sure that it is tight.
lay the bottle on it’s side in the pan full of ice.
slowly pour the pitcher of ice water onto the bottle.
stand the bottle up and observe what happens. the plastic bottle has been crushed in. 