My engineering assignment calls for me to create a launcher that will propel a jumbo marshmallow at a target 50 feet away. I’m really excited about this assignment since this will be the first thing I’ve ever constructed on my own, but I’m unsure about finding inexpensive materials (my launcher cannot exceed $25). I recently discover PVC pipes as a cheap way of constructing a cannon & I began working on a http://home.earthlink.net/~copper017/Random/idea.jpg [Broken]. I would like to have a release chamber that contains pressurized air so that the air will force the marshmallow to its target once it is lodged into my device. In order to do this, I would like to use an air pump to fill the chamber with air, but I don’t know if I will get the Will PVC pipes be okay to use for air pressure? If not, what type of pipes or materials can I use to construct an inexpensive pressure chamber? Thanks in advance for the advice.