On Wednesday April 25, 2018 kids came to Pasadena Library to learn about elastic energy and the Law of Conservation of Energy, and then build a helicopter that would rise up in the air despite its weight. We attached helium balloons to a homemade helicopter that runs on elastic energy, and since the apparatus itself is heavy, the whole thing generally floats gently down. (Some kids did have to add a weight in order to counteract the extreme lift of the helium.) Kids had a blast making their helicopters even though it was not an easy project, and required a lot of tinkering and troubleshooting!

First I did a science presentation with the kids. I explained the Law of Conservation of Energy and we discussed some examples of kinetic energy, using a game I created a few years ago on Scratch:


Then we get into making the blades of our helicopter. I made two iterations of this project myself during the day, in order to get a strong feel for what troubleshooting issues may come up.

First version: long paper plate blades:

When trying my first one out, I got frustrated that it stopped working after a few spins. I learned that my paper plate blades were probably a bit heavy, and also that the rubber bands slowly wear down their ability to store elastic energy. I also was using a wooden skewer for the blades and the wood seemed to generate too much friction. I switched to an unbent paperclip like in Curiosity Machine’s original model. But even with the reduction in friction, my blades still weren’t turning fast enough.

I took the plates off and found that the paperclip by itself would spin very fast. So I tried to make blades that would reduce the pull or drag on the paperclip. In the end, small, simple construction paper blades required the least amount of energy to turn. I could spin them and release them and watch my whole machine shoot up in the air!

Second version: smaller construction paper blades:

Here’s another video of me demonstrating the construction paper version to the class:

And here’s a video of a kid showing us his finished balloon helicopter!

And this next kid had a really hard time with his, and sometimes the materials came apart. But he kept at it and got results! Personally those outcomes are my favorite because the kids learn that things don’t always come easy, but that doesn’t mean you give up–you have to develop a zest for tweaking it and trying again.

I was really lucky to have a volunteer, a student I’m mentoring who is working on getting her master’s degree, to help me. She gave me a hand with setup and cleanup, taking pictures and videos, passing out materials, and helping the kids troubleshoot. She also created our flyer for the program!

Thank you so much Jess for your help! And thank you to all the kids and parents who participated!