I dont think this is an instructable but I can still show it to everyone here. The bottle cap that shoots off hits pretty hard, it gave my brother brusies. This is my first instructableso dont be too harsh with the comments.
Step 1: Materials and Some Knoledge
What you need:
A water bottle(0.5 liter poland spring is easiest to use)
The only reason the cap shoots off was because of the air pressure you created by twisting the bottom of the water bottle.
Step 2: Getting Started!!!
Ok, to get started, drink all of the water in your water bottle, save the cap, thats the projectile.
To make the next step easier, start pinching the area shown by the picture, on the Poland Spring water bottle, its the indented ring under the paper wrapper.
Step 3: Start Twisting!!!
Start twisting the area you have been pinching
The more you pinch, the harder and farther the bottle will shoot.
I didnt twist as much because I was only doing it for the instructable...
Step 4: Fire!!!
Noww still holding it as shown in the previous picture, with your free hand, twist off the cap with your free hands thumb.
The cap should fly off with a loud(or kinda loud)pop. If it doesnt than you should practice the technique of flipping off the cap.
(Note: You cannot use the same bottle twice or you will not have the full effectz6)