Good morning everyone, today I announce that my first physics project will be done with projectile motion.How will I do that? Well, throwing a ball is boring after a while and can be very tiring after many throws. Guns are cool and the effects are more dramatic but a little too dangerous for this project. The 'cannon' in the picture is a happy alternative. It is a compressed air cannon made out of PVC that operates around 60 psi and is designed to shoot water balloons. My aerospace engineering friend(also in the picture holding the cannon in the yellow shirt) and I made the cannon out of boredom one weekend and had fun with it until it broke last spring. My plan is to rebuild it and improve on the basic design we had.
DISCLAIMER: Please do not try to duplicate this project at home! There is some danger associated with this project and also can be illegal in some areas of the country.
So since that is out of the way, the question is how will I be keeping in line with my blog's original purpose of physics education and furthering science through a water balloon cannon? The answer is to use the scientific method to try and accomplish some goal.
Here are the steps as defined on wikipedia's article on the scientific method
1. Define the question
2. Gather information and resources (observe)
3. Form hypothesis
4. Perform experiment and collect data
5. Analyze data
6. Interpret data and draw conclusions that serve as a starting point for new hypothesis
7. Publish results
8. Retest (frequently done by other scientists)
The question for this project is:
Can a home-made compressed air cannon be made accurate enough to hit a 50-Gallon drum from 200 meters consistantly, ie 3+ shots in a row, with water balloons?
So now begins the second step, information gathering. The next post will be about basic projectile motion and other theories involved with this project.
Do you think this project is a reasonable one? Too easy? Too hard? Too dangerous? Feedback is always appriciated.
JPLittleton
Posts
200 meters seems to be a hell of a long way for a water balloon. I can't remember how long it shot last spring, was it 200m? Other than that, sounds fine to me, though I doubt the possible accuracy of a water balloon due to aeroelasticity problems and variances in volume and shape between one balloon and the next.
ReplyDeleteHow are you going to be able to take wind into account? Will you be shooting the cannon indoors instead? The weight, size, and type of balloon used may also affect how far and accurate the water balloon will go.
ReplyDeleteJonathan,
ReplyDeleteYes it is a long way but I wanted to set up a real challenge for this project. We shot about 120m uphill with a less than ideal setup and we were only shooting at 60psi rather than close to the 120psi that we know it could take. The tank is being rebuilt and could possibly take some higher pressures. If we get the ideal setup I think the range is completely possible. As for the accuracy, that is part of the experiment. Even if the accuracy isn't that great, the next question will be how accurate can we get it?
Steve,
Wind will be a factor and we will wait for an ideal day to shoot with minimal wind. We will use a consistent amount of water for the balloons, same balloon type, and build a stand for the launcher to ensure consistent launch angles.
Thanks for the feedback!
JPL