For our Maker Faire project, Zoe and I decided to make mini launchers out of office and school supplies such as pencils, pens, binder clips, and rubber bands. We chose this project for a number of reasons. First, the idea of flinging things like blueberries and grapes was appealing, because Zoe and I both like launching things. Also, we had the idea for a "blueberry cannon" for a while after some blueberries started mysteriously rocketing over the fence. Another reason we liked this project was that at our booth, people could come and shoot things, (there would be a hands-on, interactive approach). Our objective in this project was to create cool catapults that actually launched pretty far, in order to make boring old school supplies more fun. We made the CD Catapult, the Viking Catapult, the Clothespin Chaos Catapult, the Binder clip Blaster, and clothespin darts. Some criteria were safety, we didn't want anyone to get hit in the eye, function, we wanted it to actually shoot, and we needed it to launch pretty far. Some constraints were our lack of skill with pliers, we found out, finding the necessary supplies, and being able to finish it in the time constraints.
For anyone who is confused (I just kind of rocketed into an explanation, as always), Zoe and I read up on catapults prior to the project and learned some things about them. The main parts of a catapult are the main block, or the frame, that holds it together, the arm, which you pull back, something on the end of the arm to hold whatever you're pulling back, a base, a clamp, and a lever that has the rubber band attached to it. The rubber band (or whatever you're stretching back) can also be connected to the arm, to create and release tension. On this site, you can find some fun catapult projects to do at home.
Our design process was based off of some designs from a book called Mini Weapons of Mass Destruction. We improved a lot on their designs and changed some steps and materials according to what we had available and what we thought would function better. First, we drew out our designs, and then collected materials for whatever catapult we were making. Next, we put together the launcher, occasionally referring to the book but adding in many steps as we went. Penultimately, we went outside and tried launching them with first a blue pom-pom so no one got hurt, and then with blueberries and marbles. Last, if they didn't shoot, or didn't go very far, we tried out new methods to shoot them, replaced rubber bands, or tinkered with them a bit (in some cases a lot). Some fun parts of our project were "testing out" the launchers, and watching our classmates as they tried to launch them.
Even though Commander Momitchi and Commander Hiro (me and Zoe) came out with a very successful project at the Maker Faire, there are still things we could add on to our army. Some next steps would be finishing our trebuchet, which we started and never finished. In case you're wondering, it uses a battery as a counter-weight, which swings into an eraser that flies off (basically, too complicated for the 50 minutes we had left). We could also add wheels to our catapults so that they would move freely, or put them on stilts so they were taller. We could also have made more weapons, and an idea we had was spray-painting them all silver so they looked uniform (although then you wouldn't be able to see what they were made of and we think that is cool). Another idea could be completely cutting ourselves off from our very inspirational book after a few projects and designing a catapult all on our own, which we would do if we had more time.
For anyone looking to replicate our project, make sure to use a ruler when creating anything that needs to be even, as that was a problem, and make sure to be careful with X-acto knives. We recommend Mini Weapons of Mass Destruction as a starting point, but don't take everything they say for granted. A lot of times, when the author says use rubber bands, it's better to use duct tape even though that isn't technically an office supply. Try shooting the catapults at least ten times in different ways, (i.e. rubber band in a different position, different height, two rubber bands instead of one...), before you make your final decision as you might discover something you've overlooked. Another important tip: don't make anything permanent! We had to do many last minute fixes, and on one catapult, we had to take it apart many times because the arm, a spoon, was turned the wrong way, then the rubber band was on the wrong side, so we changed the spoon back, but we shouldn't have, and so on. Don't be afraid to play with your "finished product", because for us, they're never finished.
We learned a lot through this process. We developed better teamwork skills, and learned that we focus very well together and don't distract each other. We learned a lot about building with duct tape and school supplies, including the strengths and limits of each material. For example, Popsicle sticks break when you bend them over and over, and in some cases, it's better to use duct tape than to lash things together with a rubber band like it says in the book. Also, it's very hard to get a small binder clip sideways onto a popsicle stick, don't try it. We learned that we could condense steps from the book and throw out ones that we didn't need, like the binder clip/popsicle stick step I mentioned before.
One frustrating glitch in our project came when we were making the "Original Blueberry Launcher" catapult out of a CD spindle casing. We had to make holes for pencils to go in through the plastic on either side of the cylinder. We had to reinforce the brittle plastic with duct tape so it wouldn't snap- but that was where the problem started. We tried an X-acto knife, a box cutter, and scissors, which all failed to cut out a hole. By poking and twisting at it with a screw, we managed to make a small hole which barely came through. The next day, we had the brilliant idea to drill it, but Ms. Mytko was at a 3D printing convention and we didn't know where the drills were, despite looking in the drawer labeled "Tools". Finally, we had the bright idea to use a hot glue gun to melt holes (which may or may not be toxic). Our best method after trial and error, was making a small dent with hot glue, poking it through with a screw, widening it with a pencil, then more hot glue, and finally more widening with a pencil until we got the right shape.
Overall, our Maker Faire project, blueberry launchers, was fun, successful, and taught us a lot about structural design of weapons.