Model Rockets and STEM Education

Last weekend, my son received a model rocket kit for his sixth birthday. Having built and launched rockets when I was a kid, I was excited to take it out to a local soccer field and try it out. The smell of burnt-out engines immediately brought back memories of my own rocketry adventures.

For those unfamiliar with the hobby, model rockets are small, lightweight scale models made of a cardboard tube, plastic nose cone and plastic or balsa fins. Rockets are powered by small, cylindrical engines – most of which use black powder propellants – inserted into the tail end. Hobbyists plug an electric match into the nozzle end of the engine and ignite the propellant using a battery-powered controller clipped to the match’s wire. The whole apparatus is fired off of a launch pad with a thin vertical rod to guide the rocket’s trajectory.

While combining children and black powder might not seem like the best idea, model rocketry is a safe and enjoyable hobby. For a kid my son’s age, model rocketry is great on a few levels. On one hand, people of any age generally get a thrill launching anything hundreds or thousands of feet in the air. But model rocketry can also provide an opportunity for education in science and engineering.

Choosing an engine for a flight is a good place to start. Low-power commercial rocket engines are rated using a [letter][number]-[number] system. The letter indicates the engine’s class, which describes its total impulse. For example, “A” engines have a total impulse of between 1.26 to 2.5 newton-seconds, while “C” engines have a total impulse of between 5.01 and 10 newton-seconds. The first number represents average thrust, expressed in newtons. The second number is the delay, in seconds, between propellant burnout and the ejection charge, which deploys the parachute or other recovery system.

Parents of younger kids will obviously want to keep the physics to a minimum, but a child as young as six could understand the importance of choosing the correct engine. A heavier or larger-diameter rocket that needs more thrust to get off the pad would benefit from a higher first number. And it’s easy to explain that launching in a smaller field on a windy day would call for less total impulse, unless the kid never wants to see his or her rocket again.

Finally, kids and parents can experiment with different delay times relative to the size and shape of the rocket. Too little delay and the parachute may deploy while the rocket is still coasting; too much and it may hit the ground before the recovery system deploys. Kids can benefit from learning that no flight is a failure if they’re able to learn more about an ideal engine for their particular model.

Older kids would likely benefit from a more in-depth explanation of engine performance, maybe even including graphs, curves and formulas. NASA maintains a helpful Beginner’s Guide to Rockets that goes into detail about aerodynamics, thermodynamics and propulsion systems.

Have you tried model rocketry, either alone or with kids? If so, did you try to incorporate STEM education?

Image credits: Justin Lebar / CC BY-SA 3.0; U.S. Air Force photo)