Water Bottle Rocket First Launch

Today we practiced launching the soda bottles. In order to become familiar with the equipment, we decided to set up our own launchers. First we filled the bottle with 500 milliliters of water. (For the actual launch, we may use up to 1000 milliliters.) Because the water is the fuel, this is pretty important. Next, we set up the bottle with the rubber cork so that we would be able to create pressure that would enable our bottle to take off. We used the pump to create pressure in the bottle so that it would be able to fly. Our first attempt was pretty successful. Here's a picture of the bottle after the first attempt.

Unfortunately, our second attempt was not as lucky. It tipped over sideways and for a second someone was almost in danger of becoming bruised before her tennis match. I guess we'll try not to repeat that second time. Here's a funny video of that launch.

Because we want to add fins to the bottle using super glue, we will have to put water in the bottle as well as put the cap on the bottle. This will create pressure that will keep the bottle from losing its shape from the heat of the glue. (If that happens, we will be unable to use the bottle because it won't be able to launch correctly.)

Austin Edit:

So today we had the opportunity to launch our bottles into the air.  Marisa and I did it twice.  This is because the first time we did it almost perfect.  But we forgot to film it.  So we did it a second time.  The second time, however, got messed up.  I think that when I pulled the string connected to the bottle, I tipped it and it caused the bottle to tip over then shoot.  If you look closely to the video, you can see where it messed up.

Anyways, I think for the bottle itself, if I didn't mess it up, I think that we should indeed add wings to the bottle to help stabilize it.  And for the tip of the bottle, a rounded top would be very effective to the length of time in the air.  Hopefully the mass is very little, then all we have to worry about is minimizing the surface area, to prevent air resistance more.  Next time hopefully we can set it up a little better.