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Chemistry Cannon

May 2, 2014

You haven’t lived until you’ve seen a ping-pong ball cannon in action. I didn’t know this to be fact until about 11:00 a.m. this morning when Dr. Harvey Johnson invited me to his AS Chemistry class.

Johnson had spent the past few days coaching his students through questions on temperature and pressure on a molecular level, air molecule collisions and Newton’s second law of motion. He decided to cap-off the week by letting the class test a mathematical model they developed showing air molecules moving at 500 meters/sec. Hence, the need for a cannon made with a vacuum and a PVC pipe with a circumference slightly larger than a ping-pong ball. (Watch it in action here.)

To get to this point, the students successfully built an expert’s understanding of how air molecules relate to volume, pressure and force. By most accounts, the process was marked by frustration, struggle, and failure. But they all got there together. “The beauty of science,” says Johnson, “is that we don’t move backwards. We just keep ratcheting up.”

I felt a sense of ratcheting up beyond the classroom this week. The VI Form hosted a Prom Weekend for the ages with three dances, two bands, and at least one recorded instance of crowd-surfing in the library. The IV Form chapel service offered moments of great humor, introspection, and wisdom. Ryan Bellissimo ’16 raised money for the Wounded Warrior Project. Adam Gelman ’17 helped us honor and remember those who died in the Holocaust. Students participated in the Day of Silence to call attention to the silencing effect of anti-LGBT harassment in schools. Johnson’s refrain provided a steady drumbeat: “We don’t move backwards. We just keep ratcheting up.”

And so there I was, hiding behind the door frame of the chemistry classroom with Grayson Ahl ’15 pointing the cannon in my direction. You don’t really see the ping-pong ball after the cannon operator pokes a hole in the pipe’s seal to release the pressure and allow air to rush in. It’s a bang and a streak followed by confusion and a search for its remains. And then you do it again. Maybe it can go a little faster. Maybe it can go a little farther. “We don’t move backwards. We just keep ratcheting up.”

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