Hover crafts are such an interesting concept. With the popularity of hover boards and all things drones, I couldn’t think of a better experiment to teach about air pressure to the boys. Hover crafts move people and items across water, ice, and land. It is also called an Air Cushioned Vehicle. These machines use air to reduce the sliding friction between the bottom of the vehicle and the ground.
There is air surrounding us everywhere, all at the same pressure. You feel the same force on your skin whether you’re on the ceiling, the floor, in your car, or water. What happens when you change a pocket of air pressure? You get movement!
In this experiment the balloon has a higher pressure inside than the surrounding air. When the air begins to flow through the hole in the film cannister or bottle top the steady stream of air flows under the CD and creates a cushion of air. This raises the whole hovercraft up slightly… which makes it glide across a flat surface.
Let’s put it together:
You will need:
A large balloon
A CD
Poster Putty or Hot Glue
Water Bottle Pull Top, or Film Cannister
If you are using a film cannister, you will need to drill a small hole in the bottom of the closed side of the cannister before beginning.
Step One: Place your balloon opening over the open end of the cannister or bottle top.
Step Two: Put poster putty around the hole of the cannister close to the circle, but not covering it. You don’t want too much as it can seep into the hole and block the air way. Just enough is needed to secure the cannister and create an air tight seal. If you are using a bottle top, you can put the putty around the outside of the bottle lid. If you will be using hot glue, you will place the glue in a circle around the hole in the same way as pictured.
Step Three: Press the cannister to the CD. You will want to line the holes up so the air can flow out of the balloon through the CD hole. You want to make sure that your holes are lined up and that the putty or hot glue is not covering the CD hole at all. Make sure that you have a firm seal and the balloon is attached to the CD securely.
Step 4: Blow up your balloon. It may feel weird, but it is completely possible. Put your lips around the CD hole and begin to blow. Make sure to get enough air into the balloon that it has enough air to force out. Once the balloon is blown up, make sure that you are holding the stem tightly to not release any of the air out until you are ready.
Step 5: Flip your hover craft over onto a flat surface and release your hand to let the air out. You may need to give it a little nudge to get it moving at first. Once the air is coming out in a constant stream, your hover craft will begin gliding across the table.
You could get real creative with this and make two hover crafts and have an air hockey battle with a coin. It may also be fun to experiment with how you could make it go faster or slower. This is the fun part of science. You provide the experiment, and then let your kid’s minds go wild with creativity on how they can improve or change the experiment. Believe me, they will have ideas. It is our job to guide them and encourage them to be innovative thinkers!!
Links to products:
Balloons: https://amzn.to/3k6Vkf0
Film Cannisters: https://amzn.to/3k8EAUB
Bottle Tops: https://amzn.to/3YLosr0
Poster Putty: https://amzn.to/3EkyKq7
Hot Glue Gun: https://amzn.to/3EkZUwX