Summarize the following:
A basic plastic bottle of water you purchase from the store works well. Any brand will do, and the size of the bottle doesn't particularly matter. Make sure the water bottle is easy to carry and can hold enough liquid to last a water fight! Water bottles come in a variety of shapes and sizes. Use a small drill or nail to create a small hole in the cap of the bottle. This is where the water will be shot from. The size of the hole will determine the size of the stream, and thus, how quickly water is expended. An awl and small hammer may also be used to easily create a hole in the bottle cap. Water bottles that have a "squeeze" top can be used as a water gun right off the bat! Just pull the top open and squeeze the bottle to launch a stream of water. Squeeze the body of the water bottle to produce a stream of water. This method only works using the air within the bottle and the remaining liquid. It's fairly limited in terms of stream and volume, but can do in a pinch.
Purchase a water bottle. Pierce a small hole in the bottle cap. Squeeze the water bottle.