Rocket Science at Home: Build a simple rocket launcher!

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This simple experiment packs a knowledge punch. It’s easy and quick to put together!

This experiment utilizes potential and kinetic energy to blast our plastic cup rocket off. By pressing down on the rocket, we are building potential energy that is converted into kinetic energy when we let go and let our rocket fly.

“GO” for launch in 3, 2, 1… BLAST OFF!

How to make the Rocket Science at Home engineering experiment

Supplies you will need

For this experiment, you will need the following:

  • 2 plastic cups
  • 3 rubber bands
Supplies needed for the Rocket Science Simple Cup Rocket Launcher engineering experiment

Before you start

Be sure to keep an open area in front of your cup launcher.

Instructions

Here is how to do this experiment with your child:

Step 1: Place one rubber band around cup

Use your first rubber band to run across the opening of the cup down to the bottom of the cup.

Step 2: Place a second rubber band perpendicular to previous band

This second rubber band will be placed the same as the rubber band in the first step, but perpendicular to that band (see picture).

Step 3: Place third rubber band around cup to hold others in place

Finally, this third rubber band will hold the other two bands in place.

Place this rubber band around the cup and on top of the first two bands. If it isn’t snug enough, wrap it around once more.

Step 4: Go for launch!

Now, it’s time to get ready for launch!

Place your other cup (with no rubber bands) upside-down on a flat surface. This is our launch tower.

Take your cup with the rubber bands attached (our rocket) and also turn it upside-down.

Place your rocket down on the other cup and let go to launch!

The science and engineering behind the Rocket Science at Home engineering experiment

This experiment teaches:

  • Physics concepts, like potential and kinetic energy
  • Safety awareness
  • Cause and effect

How it works

In this experiment, we use a plain plastic cup as the launch tower and a plastic cup with rubber bands around it as the rocket.

The rubber bands allow our rocket to fly by utilizing potential and kinetic energy (more on that below).

As we push down on the rocket, we are building potential energy. When we let go of the rocket, kinetic energy takes over and our rocket goes flying!

Physics concepts

Launching a rocket involves concepts of potential energy, kinetic energy, force, and motion.

  • Potential energy: Similar to the Catapults experimentOpens in a new tab., we can use this experiment to teach about potential and kinetic energy. Potential energy is the energy stored up that depends on the individual parts of the system (our rocket and launch tower). As we push the rocket down on the launch tower, we are building potential energy.
  • Kinetic energy: When we let go of our rocket and it launches, that potential energy transfers to kinetic energy (energy due to motion). Kinetic energy is calculated from the object’s (our rocket’s) mass times the velocity. Since the mass of the cup doesn’t change, it depends on the velocity. Once our rocket slows down or crashes, it changes drops or zeroes out the kinetic energy!
  • Force: There are tons of forces in motion when we launch our plastic cup rocket launcher. From the force of the rubber bands to the force from the weight of our cup, there are forces that act on our rocket and control how far and fast it will fly.
  • Motion: One lesson our kids can take from this experiment on motion is learning about projectile motion. You can take a video of your rocket launching and slow it down to observe the path the rocket took right after launch (should be close to a curved path up, then down). Use that opportunity to talk about projectile motion!

Safety awareness

Launching a rocket involves safety considerations. We can use this opportunity to talk to our kids about not being in the way when we launch a rocket.

Cause and effect

This is an easy experiment for your child to be in control, which is a great opportunity for them to experiment with cause and effect.

They are able to control how much force they add to the launcher to see how high their rocket will fly, can see what happens if they change the angle of the launcher, or even experiment with how many rubber bands they use on the rocket to see how it affects the flight.

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