Boom! Potatoes Soar as the Physics Potato Cannon Tradition Continues


Mr. Heraghty prepares to launch a potato, as his class waits across the field hoping to catch it.

Around 15 years ago, Mr. Heraghty and his Physics class built the first potato cannon. Since then, Mr Heraghty, a Nanuet science teacher for 20 years,  puts his student knowledge to the test in a demonstration students themselves participate in. This tradition features the potato cannon, launching starchy ammunition at speeds around 75 miles per hour, and slowing down to a mere 15 after its 4 second flight. 

The potato cannon is made of 2-4 feet of durable PVC piping. Using a ramrod, a potato is pushed down the barrel, which itself is connected to a large compartment (the “engine”). Diluted alcohol spray is ignited to create pressure and launch the potato.

Students often take on the challenge of catching the projectile. Despite how much the potato slows down, its unusual shape can make it difficult to grab from across Nanuet’s lower field. However, when students manage the feat, it doesn’t go without an enticing award.”

“The last student to catch a potato was during the 2015-2016 school year,” Mr. Heraghty said. “Their reward for the catch was an automatic 100% on any lab of their choosing.” 

This year, junior Gabby Santos was the closest to catching the potato at this year’s launch during Mr. Heraghty’s Physics 101 class.

“It looked invisible in the air,” Santos said. “Once it came down, you could see it.” 

The potato cannon event, similar to the rocket launch in the spring, also ties in with the physics curriculum. 

“The potato cannon demonstrates projectile, or parabolic, motion,” Mr Heraghty explained. “Using one of the football fields, students measure how far the potato lands horizontally and its flight time. With horizontal distance and flight time, students can determine many other values: maximum height, initial velocity, kinetic energy, [and] potential energy.”

Mr Reinertsen, who teaches alongside Mr. Heraghty, was present for this year’s cannon launch.

“Physics is fascinating; everything can be reduced to basic algebraic equations,” he said. “I love to impart this to my students.”