Backpack Science with Ken Finn: Rig a Rocketship

Backpack Science

Backpack Science is a summer series of easy at-home experiments geek dads can perform with their kids while school’s out. It is written by (San Francisco) Exploratorium science educator Ken Finn. This article is #6; you can find the whole series here.

Rig a Rocketship

Rocket experiments are the essential at-home projects that kids just live for. These rockets, outlined in the experiment here, are quite simple, safe and easy to do. When my daughters and I do this at home, we like to investigate variations in fin design to discover what will make the rocket fly straightest. You can also experiment with weight distribution to see what makes the rocket fly farthest. Or, you can just randomly shoot it into the air and cross your fingers — another highly scientific approach to this one.

What you’ll need:

  • 2-L soda bottle
  • 3 feet (90 cm) clear, flexible vinyl tubing with ½-inch (1.3-cm) interior diameter and ⅝-inch (1.6-cm) exterior diameter
  • duct tape
  • 2 feet (60 cm) PVC pipe with ½-inch (1.3-cm) interior diameter
  • sheet of blank paper
  • clear tape
  • 3-by-5-inch (8-by-13-cm) index card
  • scissors
  • a rocket-loving friend

How it’s done:

  1. Uncap the soda bottle and stick about 1 inch (2.5 cm) of vinyl tubing into it. Duct-tape the tubing in place — make sure the connection is airtight.
  2. Line up the PVC pipe with the tubing’s free end. Duct-tape them together. Now you’ve got a rocket launcher!
  3. Roll the paper around the PVC pipe in a tube loose enough to slide on and off. Tape the tube together and take it off the pipe.
  4. Twist the end of the paper tube into the rocket’s “nose.” Tape the twist in place and mash it until it’s pointy.
  5. Now you gotta have rocket fins. Fold the index card in half. Cut along the fold line. Stack the halves and cut them diagonally, like a sandwich, to make four fins.
  6. Tape the fins evenly around the base of the paper rocket.
  7. Call a friend to meet you outside. Put the rocket over the PVC tube, and ask your friend to hold the tube up but pointed away from your faces.
  8. Three — two — one — blastoff! Stomp on the bottle and watch that rocket soar.
  9. Now your pal gets a turn. Reinflate the bottle by blowing into the PVC tube.

Rig a Rocketship, excerpted with permission from Exploralab, 2013, published by Weldon Owen © Exploratorium, All Rights Reserved.

Ken Finn

About Ken Finn

Ken Finn is a science educator at San Francisco's Exploratorium museum and a co-author of the upcoming Exploralab book, available for purchase in the Exploratorium Store on September 24, 2013. And most importantly, Ken is one seriously geeky dad who often enlists his two daughters as partners in crime for all his zany Backpack Science experiments.

Ken Finn

About Ken Finn

Ken Finn is a science educator at San Francisco's Exploratorium museum and a co-author of the upcoming Exploralab book, available for purchase in the Exploratorium Store on September 24, 2013. And most importantly, Ken is one seriously geeky dad who often enlists his two daughters as partners in crime for all his zany Backpack Science experiments.

One thought on “Backpack Science with Ken Finn: Rig a Rocketship

  1. Any chance of a diagram? I have a slight idea from seeing something like this somewhere else, but these directions leave me guessing on how it should look. I’d rather experiment on the fin design and not just getting it to work.

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