Method Log
Day 1: We research the principles behind building a pneumatic cannon. The TuHS physics page and resources listed therein were useful. We used a modified design for a paintball cannon.
Day 2: We gather materials and begin construction. Also, the solenoid is difficult to track down. We went to The Home Depot to find a sprinkler solenoid, but were informed by the plumbing expert there that the sprinkler solenoids would not work, and that The Home Depot does not have them. On further inspection, we find that sprinkler solenoids were in stock in the irrigation section, and we decided to trust the people that have made these types of cannons before over the man who has no experience with such delinquency.
Day 3: More construction. We also find that airtight seals are nearly impossible to obtain. We find that PVC glue does not work correctly on ABS pipe, so we buy ABS glue.
Day 4: We attempt preliminary testing of our cannon. We also manage to knock the nipple out, therefore making us take it all apart to fix the nipple. Imagine a card house- if one of the bottom cards fall, they all do. Same principle.
Day 5: The ABS glue dries, so we finish making different sized barrels. We then test the cannon, but a small leak develops. We live with it, and continue collecting preliminary data. We find out later that this is a bad choice.
Day 6: The leak increases, making it impossible to collect data. We figure out that glued seals are better than those made with Teflon tape around threads. So we glue all of our seals.
Day 7: The glued seals do not work, and we are left with unalterable leaks. So we decide to scrap that section and rebuild it.
Day 8: The leaks are minimal, however the glue seals do not completely dry, and air pressure causes our cannon’s compression chamber to explode at the seal. We glue it back on, try again, and it explodes again. So we let the third coat of glue dry overnight.
Day 9: We find that there are more leaks, but at different spots than the previously sealed joints, so we re-Teflon the seals and tighten them. The leaks disappeared, but a new one formed in a different joint. We sealed it with Teflon, but it didn’t work, so we eventually glued the threads together. This appears to have solved the problem.
Day 10: Data collection and analysis.