Houston, we have lift-off! This fun activity will turn your local stomping grounds into a rocket launch facility.
You will need
- 2 one-metre lengths of 15 mm wide PVC pipe
- 2 15 mm PVC tee junctions,
- Empty and clean 1.25 L soft drink bottle
- Hand saw or PVC pipe cutter
- Duct tape or packing tape
- Masking tape
- Sharpie or pen
- Measuring tape
- 2+ sheets coloured construction paper
- Scissors
- Timer (optional)
Safety
This activity involves sawing off lengths of PVC pipe; an adult is required to complete this step. This activity involves going outside. Be sun-safe and ask an adult to supervise you during this activity. When launching rockets, use only one leg to stomp the plastic bottle and make sure no one is near the rocket before launching it.
Build the launcher
Take one of your 1-metre-long PVC pipes. Use a tape measure and sharpie to mark 25 cm, 50 cm and 75 cm on the pipe.
Ask an adult to cut the PVC pipe at your marked locations. You should end up with four 25 cm lengths.
Take one of the PVC tee attachments and stick the one-metre pipe into one side. Put a 25 cm pipe into the other side and into the other hole.
Take your clean 1.25L bottle and attach its opening to the free end of the 1-metre pipe. The neck of the bottle should slot right into the PVC pipe. Use duct tape to secure it.
The middle pipe is where the rocket launches from, and the pipe furthest from the bottle will be a stand to keep everything pointed in the right direction. Insert the other end of the stand pipe into the middle of the second tee piece.
Put 25 cm pipes into the two arms of the second tee piece.
Adjust the rocket launch pipe so it points straight up.
Use duct tape to cover each of the PVC pipe openings on either end of the T-shape. Don’t cover the rocket launch pipe, or your rockets won’t launch!
Make a rocket
Fold a piece of construction paper in half, halving the length (fold hamburger style, not hot dog).
Cut the paper down the crease you just made to make two pieces.
Take one of the pieces of paper and wrap it around the rocket launch pipe. The tall side of the paper should be parallel to the pipe. You want it snug, but it needs to be able to slide or the rocket won’t launch.
Use masking tape to secure the paper cylinder’s shape.
Slide the paper tube up so about 1 cm is above the end of the plastic tube.
Fold the edges of the cylinder down to make a cap, and tape it all down.
Take the other half of the paper and cut a triangle to use as a fin for your rocket.
Use your triangle as a template to make 2 more of the same shape.
Tape the three fins to the rocket, spacing them evenly around the base. Your rocket is ready for launch!
(optional) Can you make improvements to your rockets? What happens when you use 4 fins or a pointy nosecone?
Lift-off!
Go outside and place your launcher in an open area, a long way from cars and other people.
Take one of your rockets and place the open end over the PVC pipe section that sticks up.
Make sure no one is near the rocket.
Use one leg to stomp on the plastic bottle to launch your rocket! Aim to stomp on the middle, over where the label goes on the bottle. Don’t stomp on the top or bottom ends of the bottle as these areas are less flexible and might break.
Use a timer: how long did your rocket stay in the air?
To re-inflate the plastic bottle, wrap your hand around the vertical pipe and blow into the pipe through your hand. Using your hand instead of blowing directly onto the pipe reduces the spread of germs.
What’s happening?
Stomp rockets are all about harnessing the power of compressed air. By stomping on the plastic bottle, you suddenly make its volume much smaller. A smaller volume means the air molecules inside get squished or ‘compressed’ together. Compressed molecules bump into each other and the bottle’s walls more often. The tiny force each molecule exerts when bumping against the bottle’s walls adds up to increased air pressure inside the bottle. This is the first step towards launch.
Air molecules spread from areas of high pressure to areas of lower pressure. This means the compressed air in the bottle will rush into the PVC piping. But PVC pipe can’t expand, and you covered all the openings! So, the air pressure increases inside the entire PVC piping, too. All that pressure pushes in all directions, but there’s only one piece that will move out of the way – your paper rocket!
Launching space rockets
Space rockets make use of compressed gas, too. The main difference between a real rocket and your stomp rocket is that it keeps using compressed gas after launch.
Space rockets often start with compressed gas. For example, United Launch Alliance’s new Vulcan rocket is fuelled by compressed oxygen and methane. The gases are then combined in a controlled explosion, which rocket scientists call “combustion”, raising the pressure even higher. The resulting gas fires itself out through the bell-shaped nozzles in the bottom of the rocket. Meanwhile, that gas is also pushing just as hard, back on those nozzles. Houston, we have lift off!
Leave a Reply