Launching rockets requires a lot complicated math, but it all starts with Newton’s Laws of Motion. We’re going to get a taste of the math behind the real rocket science.

Click the button below to download the Student Worksheet that goes with this lesson

Using math with rocket science experiments allow scientists to figure out important information about the rocket structure, flight, and performance before it ever leaves the ground.

Rockets are more complicated than it might first seem. For example, as a rocket burns through its fuel, it gets lighter, which makes it easier to move through the atmosphere. Also the pressure inside the combustion chamber must be higher pressure than the outside pressure in order for the gases to escape and push out through the nozzle, which is helped by the fact that as a rocket moves up through the atmosphere, there’s less and less atmosphere for it to move through (which also means the drag force decreases). All of these things increase the acceleration (how fast speed changes when moving in a straight line) of the rocket.

Newton’s Second Law can be formally states as the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.

Whew… that’s a lot to remember, isn’t it? Let’s try a math equation instead that says the same thing: Fnet = m a

Fnet are the forces acting on the rocket. This includes weight, drag, thrust and lift for flying objects.

m is the mass of the rocket. Remember, this is changing as the rocket burns through its fuel.

a is the acceleration of the rocket. That’s how fast the rocket is changing speed if it’s going in a straight line.

Note: If you’ve never heard of net force before, know that it is the vector sum of all the forces acting on the object. A rocket has a force on it due to its weight, which points toward the center of the Earth. There’s also a force on the rocket from the atmosphere called drag, and it acts in the opposite direction to the motion of the rocket. There’s another force due from the gases exiting the nozzle, and those act in the direction of the motion of the rocket. This part isn’t really important for today’s lesson, but keep it in mind for later.

The equations that describe Newton’s Laws of motion can be used to figure out how fast your rocket traveled based on the distance and the time you measure during its flight. You can also find out how high your rocket flew by using another set of equations. While normally these equations are reserved for high school physics students who usually have to figure out where they came from, I’m going to give you a taste of what it’s really like to use math during a science experiment.

Don’t worry too much about these questions or where they came from. Just use them as I’ve described below and in the video so you can see how a real scientist uses math to model what’s going on with their rocket.