"Rockets! I want to build and test rockets!"
That's what my oldest son told me when we began discussing what he wanted to do for his school science fair project this year. During a class launch last year he had noticed that some rockets appeared to launch faster than others and they were all using the same rocket engine so he thought some rockets must be heavier than others or maybe the fins made a difference. For his science fair project this year what he wanted to learn about was acceleration and prove that a heavier rocket would accelerate less quickly than a lighter weight rocket.
In order to prove his hypothesis we needed to build a rocket and launch system where the only variable would be the mass of the rocket. We thought about using traditional solid propellant rocket motors but we had not devised a method of testing the motors to ensure the consistency of motor power output. For this reason we decided to use compressed air as a power source since we could accurately monitor the air pressure in the air launcher. We also liked the idea of air rockets as some solid propellant rockets that can carry a payload can reach very high altitudes and we were concerned with the possibility of losing a rocket and our data.
In order to measure the acceleration during each launch we made a very simple circuit using a three axis accelerometer with a range of +/- 16g. The data from the accelerometer was logged on a micro SD card during launch so we could analyze it later. This way we could launch over and over again during one launch session in order to try and remove weather as a variable.
This is a great project for introducing kids to the scientific process, coding, electronics, soldering and making rockets. The rockets are very inexpensive to make and once the launcher is built they cost nothing to launch and you can launch them over and over again in a very small field.
This project does require the use of a soldering iron and sharp cutting tools so be sure to take the necessary safety precautions when assembling the rocket, launcher and circuit.
Now let's gather our materials and build some rockets!
