Staff Science Shenanigans: Joe builds an air cannon

Joe demonstrates how a trash can, shower curtain and bungee cord can be turned into a cool science experiment!

Joe demonstrates how a trash can, shower curtain and bungee cord can be turned into a cool science experiment!

By: Joe Schwanebeck, Director of Education

"Don’t try this at home… try it at work, instead."

Our staff is always looking for new ways to help people have fun and connect with science. There’s a near constant e-mail exchange amongst our team with links to science blogs, news articles, YouTube videos, and ideas for scaling up experiments and science concepts to give them the "wow" factor that our participants love. From there, we start to prototype, test, and piece together new experiences before they ever see the museum floor. 

One of our most recent projects, an air cannon, made its debut at our Annual Fundraising Event and was inspired by Steve Spangler. One of the great things about it is that it’s made from things you probably have around the house: a trash can, a shower curtain liner, and some bungee cords — science doesn’t always require high-tech equipment!

Putting it all together is an easy process: Just stretch the shower curtain liner over the top of the trash can like a drum, using the bungee cords to keep it in place. Cut a hole in the middle of the bottom of the trash can, and you're ready to go!

Here’s how it works, with your daily science vocabulary thrown in: 

When the shower curtain (membrane) is hit, the air inside of the trash can (chamber) experiences increased pressure, and that forces some of the air out of the small hole (aperture) on the other end. The air that leaves the middle of that hole is moving quickly, while the air leaving around the edges of the hole gets slowed down. This makes the air fold over on itself again and again, causing a ring to move through the air. Since our air is notoriously hard to see, filling the trash can with something like fog or smoke makes it much easier to see what’s going on. 

That blast of air folding over on itself is called a vortex ring, and it’s not just a nifty party trick: vortex rings can be found in explosions, scuba diver bubbles, and weather events like microbursts. Iowans are all too familiar with another type of vortex: tornadoes.

Our air cannon is quickly becoming a hit with our participants (and staff)! Check it out in this video, then plan a visit to SCI soon to find your new favorite experience!

Joe Schwanebeck is SCI's Director of Education (and a fan of the serial comma, much to the chagrin of SCI's Communication Team). As part of his job, Joe works to align SCI's experiences with the curriculum needs of classrooms across Iowa. His desk sometimes doubles as a prototyping space for new experiments, so this blog was typed between a cardboard model of a buckyball and a test-tube filled with a greenish liquid. Joe has worked at SCI since December 2007, when he started as an Outreach Presenter.

Category: General SCI