Cass Middle class studies physics and more through catapult project
by Jon Gargis
Oct 11, 2010 | 3445 views | 0 0 comments | 16 16 recommendations | email to a friend | print
Cass Middle School science teacher Joe Baker stands amid some of the many different catapult designs created by his students. SKIP BUTLER/The Daily Tribune News
view slideshow (4 images)
Flying marshmallows, coins, golf balls and even an airborne bowling ball were a part of the science going on at Cass Middle School on Friday.

The objects were thrust into the air by the catapults built by students in Joe Baker's eighth-grade class -- devices they have had a few weeks to build as part of a semesterlong project that uses the machines with ancient roots to illustrate today's science concepts.

Students launched objects of various sizes from their contraptions, which fell into the three main categories of catapults -- mangonels, onagers and trebuchets, which also ranged in size from handheld machines to much larger versions. This is the second year Baker has inserted the catapult assignment into his science classroom's curriculum after attending a conference and seeing an educator who had implemented the project in their class.

"It's just a good reinforcement of the scientific method, but it's also introducing the things we're going to study later on in physics -- acceleration, potential energy, kinetic energy, velocity -- we tie in all the physics that we're going to learn in the second semester, and we're doing it now," Baker said. "But it's also reinforcing the scientific method, a process that takes sometimes years and years, so they get to see something unfold throughout a semester and understand that the scientific method isn't one thing that you do in one day.

"These kids, they want immediate results, this generation. They want things to happen right then and there. In science, we have to understand that a lot of things we're learning took decades to prove, decades to master or whatever," he added. "That's an example in building a catapult, that it takes a while to actually experiment with something."

Andy Brock built his catapult out of 1.5-inch PVC, wood and storm door springs over the course of a Saturday. On Friday, his machine launched a golf ball a maximum distance of 20.9 meters, or more than 68 feet.

"It goes farther at home, but I also went down a little bit of a hill when I was at home, so that's probably what it was. It didn't go as far as I thought it would go, but I guess it did better than most people's [catapults]," Brock said.

Fischer Stonewood's creation was a type of onager that launched a golf ball about 7 meters, or nearly 23 feet. His device utilized a different source of energy than Brock's machine.

"It's got bungie cords from the base to the arm at the top, and you would pull it back, and when you let it go, the inertia from the bungie cords would shoot the arm up," Stonewood said. "[In this project,] I've learned that science is fun, and I've learned how inertia works."

Stonewood's classmate Peyton Nelson went small on her project. She used popsicle sticks and glue to build a pyramid, then tied the arm for the catapult to the tip of the pyramid with a rubber band. The apparatus shot a marble a distance of 4.6 meters, or more than 15 feet.

"It worked good the first few times, but then the last time, it fell apart," Nelson said, adding that she has some work to do to improve her device. "I could use more sticks and more tape and more rubber bands.

"I've learned that making a catapult can be hard, and that if you don't do it the right way, it will definitely fall apart," she added.

While Nelson's catapult was small, one of Baker's students created a trebuchet on the opposite end of the size spectrum.

"[It] launched a bowling ball, about an 8-pound bowling ball, about 255 feet. It was about 17 feet tall and had a counterweight of about 320 pounds of concrete. You could just hear this impact when it hit the earth, this 'thud,' about 255 feet away," Baker said. "The family was pretty excited about it. ... The dad who helped out said he was pretty excited, he said he's been waiting to do something like this for a long time. The daughter helped with all the materials, putting it together."

Though many of Baker's students tested their creations Friday, and remaining students will launch today, students have a few more weeks to go in the project's timeline. They will have to tweak their creations in the hopes of making them better in time for another catapult launch day -- Dec. 16.

Brock said he already has a few improvements in mind, adding that the last few weeks of the project have taught him a good bit about the role of each piece of the catapult.

"I learned more about the mechanics behind making it -- before, I thought it was just kind of throwing some springs together, but it really does depend on where you put the different pieces," he said. "Originally, it was a lot taller, but it didn't go very far, so we had to cut [the throwing arm], and I think we cut it a little too short, but I'm going to make improvements and make it better for the December [launch]."

Building their catapults comprises only half the grade students will receive in the project. The other half will be derived from their written explanations of how their devices work.

"We have a writing test that comes up in January, and I do a lot of writing in science just to help them prepare for it," Baker said. "And I tell kids, 'Listen, if you're going to build things, you're going to make wonderful things, you've got to be able to sell it, you've got to be able to explain it. People aren't going to take you seriously if you can't write a decent sentence.'

"I'm really proud of them," he added. "These kinds of things, I don't think, are done enough, because we think a simple homework assignment doesn't get done, so they won't do this. But kids need to be challenged, and if you give them a challenge, they usually rise to the occasion, and they really surprise you. I was surprised last year, and I'm very surprised this year."