The Solid Fuel Rockets Project
Science Concepts
Force and Motion, Thrust, Center of Gravity, Newton’s Laws of Motion, Fluid Friction or
Air Resistance, Terminal Velocity
Technology Concepts
Problem Solving, Troubleshooting, Construction Processes, Systems
Engineering Concepts
Modeling, Prediction, Tech Design, Recovery Systems, Propulsion Systems, Materials Science, Problem Solving, Troubleshooting
Math Concepts
Measurement, Data Collection, Data Analysis, Using Formulae, Finding height from
Angle and distance using online calculator.
Students will learn skills related to:
Properties of materials like porosity, density, and grain.
Laminates and lamination
Properties of adhesives like solubility, adhesion, rigidity/flexibility
Proper use of adhesives, “The Right Glue for the Right Project”
Measuring
Each student will build a solid fuel rocket according to specifications given in class. The rockets will be launched with Estes A8-3 solid fuel engines. Students will measure the height of the flight by measuring the distance from the launch pad and angle formed by the apogee of the rocket flight.
The Estes A8-3 engine gives a total impulse of 2.50 Ns, and has a time delay of 3 s before the recovery system is deployed.
How are Newton’s Laws of Motion applied to rockets?
Newton’s First Law of Motion: An object at rest tends to stay at rest, and an object in motion tends to stay in motion, unless acted on by an outside force. Our rockets can’t take off without an outside force; they’ll just sit on the launch pad posing for pictures. But once they are moving, due to the impulse of the engine, they’ll stop going up after the impulse force is no longer applied. Gravity is another outside force, and it will cause the rockets to stop going up, and make them come down. They will continue in motion until the ground, another outside force, acts on them. If the “recovery system” or parachute deploys, the terminal velocity will be lowered enough that we’ll be able to fire the rockets again and again. If the chute fails to deploy we clean it up with a broom and dust pan.
Newton’s Second Law of Motion shows the relationship between force, mass, and acceleration. For example, if one of our student golfers (I don’t bend that way) hit a golf ball with a golf club, he would expect the ball to go a certain distance, and he would expect a certain amount of resistance when the club hit the ball. If the same student used the same club, with the same amount of force, and, instead of hitting a golf ball, he hit a bowling ball, would he expect the bowling ball to go as far as the golf ball? No. Would he expect that hitting the bowling ball would feel the same as hitting a golf ball? No. Of course, you could make the bowling ball go as far as the golf ball, but you would probably need a cannon.
(That explains why the main fuel tank used for space shuttle flights was orange; it was rusty. If they had painted the tank to make it “pretty and shiny”, the paint would have added tons of mass to the rocket, which would have demanded more fuel, or force, to make it accelerate to escape velocity. If you’re paying millions of dollars a pound to fire something into space, then payload is far more important than paint.)
Newton’s Third Law of Motion: For every action, there’s an equal and opposite reaction. When the fuel in the engines is ignited, the force of the blast pushing down makes the rocket go up. So the action, blast down, causes the reaction, rocket up.
