On April 28 and 29, thousands of kids, teens, teachers and families will gather in Washington DC for the National Science and Engineering festival. This is not your average science fair. This is a hands-on, get in there and experiment science fair.

To get into the spirit, we put together a super fun science and engineering project you and the kids can do at home: Balloon Racers.

There’s lots of flexibility in this project for kids to experiment, source materials and play. I’ll show you what we used, but please feel free to embellish, improve, or experiment with other materials. I’ve seen people use legos, playing cards and water bottles to construct their cars.

Here are a few teaching points you can discuss with the kids as you work on this project, depending on their age:

How you can use materials in new ways—ways they weren’t originally designed for
Why circles make good wheels
Using air as energy to propel the car
Fuel source—here, we’re using the kids’ air

For this project you’ll need:

  • Large Matchbox (in most grocery and big box stores, you can find them near the plastic utensils)
  • Xacto knife
  • Small Dowel Rods and Wheels (we picked these up in a craft shop)
  • 4 Plastic Straws
  • Balloon
  • Glue
  • Masking or Duct Tape
  • Paper
  • Hot Glue Gun
  • Ruler

Step 1
Cut a piece of paper long enough to wrap around the matchbox. If you’re using cardstock weight paper, like we did, you’ll want to use the dull side of the xacto knife to score the card. It makes it easier to wrap around the box.

Step 2
Apply glue. Wrap.

Step 3
It’s time for the axles. Measure and cut dowels to fit the width of the box plus tires. If you’re using the same wooden tires we did, add a bit of space so the dowels poke beyond the tires. You’ll see why in a bit.

Next, place an X where you’ll insert the axle. You’ll want to space them evenly, so break out those rulers.

Step 4
Use the xacto knife to cut an asterisk shape where you place the four Xs. Then push the axles through.

Step 5
Place the wheels on the axles. Test it out. How does it roll? Make adjustments as needed.

Step 6
Once your car rolls well, heat up the glue gun. Apply glue to the ends of the axles. Take a piece of a broken match stick and affix it to the dowel. This is why we needed the dowels poking beyond the wheel.

Test it again. Still rolling? Great!

Step 7
Now you’ll need to cut two holes into the car. One at the top and one at the back. You’re going to thread the straws through here, so make sure it’s large enough.

Step 8
Now it’s time for the engine. Trim the drinking straws just below the elbow. Gather them and tape tightly together. Insert the ends of the straws into the balloon and tape. You don’t want any air escaping, so tape liberally.

Step 9
Thread the straws through the car. Give it some gas.

Step 10
Watch it go!

Further play/learning opportunities: Play around with the engines. Make one using two straws. Make another using six. Which one goes faster? Add more wheels. Decorate the cars. Turn it into a tank. Take a long piece of paper and lay it on the floor. At one end write start, the other finish. Who will go off the track first?

The possibilities are endless.

Have fun with this one. And we hope to see you at the Science Festival later this month. Swing by Hall B and say hi! We’ll be making toys and showing kids how to make circuits out of salt dough. See you there!

If you want to stay a little closer to home, head on over to Robot Fest this Saturday (14th) from 10 am to 4 pm at the National Electronics Museum in Linthicum. There will be stomp rocket building (and launching), battle bots, 3D printer makerbots, and more.