Make a high speed bottle cap gun

You know when you have the cap on a water bottle and you twist it up and then flick the cap until it is unscrewed and it shoots off. Well this is like that except it goes way faster.

Step 1 Drink the water

Drink a bottle of water. Preferably an Arrowhead eco-bottle, since those are easy to crush and add pressure (if your strong enough. You will understand when you do it.)