Building Machines: Bringing the Laws of Physics to Life

Much of the material covered in the Grade 8 Conceptual Physical Science (CPS) class, is theoretical. Students learn the fundamental laws of physics. They learn about atomic structure, molecules, and chemical behavior and study the Periodic Table. But for some units, like the unit about energy, students get the opportunity to take the concepts learned in class and apply them. The energy unit was brought to life by building a machine that illustrates students' understanding of the input and output of energy and the laws of physics.

Tung Tran, Science Faculty, has been teaching CPS at King for 18 years. In his class, students work in teams to design and build "compound machines" that feature three smaller machines working together to achieve some sort of output. For the first few years he taught the class, Mr. Tran created compound machines himself to showcase the concepts being taught in the classroom. After seeing the student's interest peak with a physical demonstration, he realized there was an opportunity to let students build their own compound machines to apply their understanding directly.

Year after year, Mr. Tran is impressed with the creativity and ingenuity of his students. Projects this year ranged from a machine that could shoot a ping pong ball into a cup, to a crossbow, and a machine that could frost cupcakes. According to Mr. Tran, the machine's output doesn't have to be practical, it just has to be functional. "The important part is how students are applying the physics and the mechanics of the machine," he said.

Students Rebecca Degter and MaryAlice Smith worked together this year to create a wooden catapult that incorporated a wheel and axle, a pulley, and a lever, that could launch a toy car across the room. "The hardest part of the project was just coming up with a creative idea that no one else was doing," reflected Rebecca. The team spent hours brainstorming ideas and creating designs, which were then reviewed and approved by Mr. Tran.

The project took a lot of collaboration outside the classroom. Once their design was cleared for production, Rebecca and MaryAlice spent hours buying materials at Home Depot, testing different systems, and tweaking their design. "The best part of the project was finally making it through the process of all the trial and error and seeing it work. It was such a feeling of success," MaryAlice said.

This year, due to the large size of the Grade 8 class, Dr. Tom Castonguay, Chair of the Science Department and Director of STEM, stepped in to teach a section of CPS. Putting his own spin on the "compound machines" idea, Dr. Castonguay led his students in the design and production of their own Rube Goldberg Machines (a contraption that is deliberately over-engineered to perform a very simple task through a chain reaction - think of a more scholarly version of the game Mouse Trap). Before their designs were approved, students needed to prove their understanding of the various types of energy used to make the machine work.

The devices created in Dr. Castonguay's class incorporated a range of common household items, frankensteined together to achieve a simple output. Items like dominoes, PVC tubing, buckets, nerf guns, soft balls, marbles, wood blocks, funnels, string, toy cars, and duct tape worked together to cut a piece of fruit, push mentos into a cup of Coca Cola, or water a plant. This type of hands-on, experimental, fun learning fits well into the Next Generation Science Standards (NGSS). "These standards give local educators the flexibility to design classroom learning experiences that stimulate students' interests in science and prepares them for college, careers, and citizenship," according to NGSS website.

Students Christopher Gaine and Sammy Hillenmeyer engineered a device that, ultimately, poured cereal into a bowl. To start the contraption, a marble is placed on an incline board, which rolls into a plastic cup pulley system, which raises a second cup, that lifts a second inclined plane, which causes a second marble to roll and fall on a series of dominoes. When the last domino falls, it pulls down a string that releases a toy car sitting on a third inclined plane. As the car, attached to a second pulley system, falls off the plane, it lifts a cup holding the cereal to pour in a bowl directly beneath. If it sounds overly complex, it is. The series of actions allow students to conceptualize the various energies, how they transform (convert) and transfer to other energies, and ultimately that energy was not created nor destroyed, but that all of the energy can be accounted for when taking the entire system into account.

For Christopher, the most difficult part of the project was fine tuning the physical design so that each of the various steps successfully triggered the next. "Creating the machine took a lot of precise measurements and troubleshooting. Everything had to be exactly right for the machine to work," he explained. In fact, the first time the machine ever successfully worked was when the pair presented their design to the class.

To introduce the project, and prepare students for the challenges of building a Rube Goldberg machine, Dr. Castonguay shared a video of a 2003 Honda commercial featuring a Rube Goldberg Machine that required 607 takes to successfully shoot. "There was a lot of drama in the classroom as students experimented with their designs," commented Dr. Castonguay, "and there was a lot to be learned in the process of building and it was exciting to see the students interacting with the curriculum in a way that was meaningful and engaging."

In Mr. Tran's class, students showcase their designs at a school-wide compound machines presentation where they demonstrate their machine and explain how it works. "The project really becomes a rite of passage for MS students," said Tran. "After the presentation, Grade 6 and 7 get excited about the course, telling me what they are going to build when they take CPS."