Intro: Homemade Cork Gun
The cork gun is one of the most simple inventions that bring entertainment to many. First, you make sure there is a decent amount of air in the bottle. Then, the cork gets sanded down (I do not recommend a knife) so it can fit in the hole but not too much so it is lose. No more than 4 millimeters of cork should be in the hole. The rest should be sticking out. Twist the bottle as much as you can and put as much pressure as you can on the bottle. Depending on how strong you are it will blast out. Sometimes if you put the cork too far in it will not shoot out if you're not strong enough. Good for many hours of fun!
The other time of cork gun involves household chemicals and powders. Baking soda and vinegar. Fill a little more than half of the bottle with vinegar. Then get a decent sized piece of paper and roll it up so it looks almost like a gun cartridge holding black powder. Make sure it will fit through the hole of the bottle. Close the bottom of the paper cartridge by folding it and use a piece of tape so it holds its cylinder shape. Then fill it with baking soda. Then put the paper cartridge filled with baking soda into the bottle full of vinegar as fast as you can then quickly put the cork on. Give it a good 4-6 shakes (not too many) and hold it to your target. In seconds the cork will blast out. The farther you shove the cork in the bottle the faster and longer it will go. I've gotten mine to fire 50+ feet!
Loads of fun!