Wondering what to do with those old CDs? With a glue gun, the pop-top from a water bottle, and a balloon, your child will have a homemade hovercraft gliding across the kitchen floor in no time.
Kids should be supervised around hot glue guns and an adult should do the gluing. Small hands may need help with this experiment, but they’ll have a blast playing with it. Your family's homemade hovercraft will work best on a smooth surface.
What You’ll Need
- Glue gun
- Compact disc (CD)
- Pop-up top of a water bottle
- Balloons
- Small paper cup or a cardboard toilet paper roll
What to Do
Step 1: Glue the pop top over the hole in the center of the CD.
Step 2: Cut a slit in the side of a paper cup and cut the bottom out, or cut a toilet paper roll in half and cut a slit in one side. This will create a support for the balloon.
Step 3: Close the pop top attached to the CD so that no air can get through it.
Step 4: Blow up a balloon and secure it over the pop top.
Step 5: Place your balloon support on the CD, around the bottom of the balloon.
Step 6: When you’re ready, pull up the pop top to release air from the balloon. You may have to re-secure the support.
Step 7: Give your hovercraft a push and watch it glide across the floor or table, on a cushion of air.
Step 8: Try the experiment again with more or less air in the balloon, and have your child guess which way will work best to keep your hovercraft gliding the longest.
Enrichment: How can your child change the design of the hovercraft to make it work better? What happens if he removes the balloon support?
The Science Behind the Fun
Sir Isaac Newton was a famous and influential scientist who studied motion and gravity. One of the laws he wrote, called Newton’s Third Law, says that for every action, there is an equal and opposite reaction.
Lots of forces are at work in this experiment. When you first open the pop top on your hovercraft, air rushes out in a downwards direction (action) pushing your balloon up in the opposite direction (reaction.) The CD is heavy though, and its weight keeps the balloon from shooting into the air.
Once the pop top opens, a cushion of moving air is formed under the CD. This allows the hovercraft to stay slightly off the ground and move around freely, without rubbing on anything that might slow it down if you give it a push.
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You can find more experiments like this one at kitchenpantryscientist.com, and in my books Kitchen Science Lab for Kids (Quarry Books) and Outdoor Science Lab for Kids (Quarry Books).
Featured Photo Credit: Liz Heinecke
