Building Model Rockets
Posted June 7, 2008on:
I started building model rockets with my students this year and I’m glad I did. Most of my students have never built or launched rockets before. A few did in eighth grade, I think maybe two or three did with their parents, but out of the 100 or so seniors that I teach, that’s was it. About 80% of my students are college bound and only a couple of them are going into science or engineering, so connecting a subject like physics to something hands-on is critical to their understanding of the material. Not that I think most of them understand it, but let me delude myself please.
The school purchased one rocket for every two students. I know in some area schools, the students are required to purchase the materials. I know that most of mine could, but quite a few can’t. So the school paid for them. It took about three days to build and paint the rockets. They build, I paint. I knew I had to when one of my more trusted students came in with a rocket dripping paint. “Several light coats are better than one heavy coat.” Didn’t matter how many times I said that, apparently it didn’t stick.
The next nice day we all trudged out to the field, took lots of pictures posing with our rockets, then we launched them one at a time. I tried to explain how high and how fast they go, but until they saw it they just didn’t get it. A few dramatic failures are good. We had one tail fin fall off because it wasn’t glued on well. The rocket looped just barely over our heads. A few had the nose cone too tight. The ejector charge couldn’t pop off the nose cone, they come down fast and tend to stick in the mud. We even had one actually explode. I’ve never had that happen, I think it was an engine failure and not the work of the student. All these events add to the teachability of the lesson. We learn from our failures.
As a follow up homework assignment, they each had to write an article telling about the project, the launch, and explaining the theory to someone who hasn’t had physics. I chose two of the articles and a couple of photos and submitted it all to the school newspaper for publication.
- Each group got a single A engine with the rocket. If they wanted to launch again, they had to purchase an engine for $2. I had some B and C engines, but our field isn’t very big and we lost anything launched with C’s.
- I wanted the kids to purchase the rockets for $2, but only a few did. I would either get them to purchase them up front with their own money or just give it to them. The teams would have to decide ahead of time which of the two gets to keep the rocket.
- I bought a mix of Viking and Wizard rockets. Both are good, they use streamers for recovery rather than parachutes. A parachute in a 10 mph wind will drift twice as far as it is high. So if it goes up 500ft, it will drift 1000ft.
- Walmart is the cheapest place to find engines. A three-pack is under $5.