Well, not exactly.
A much better word for it would really be hover. But come on, what kid isn’t gonna get excited about building a hovercraft.
This is a hovercraft that NASA built. Ours won’t be as big or complicated, but they run on the same principles
The key to the hovering movement is the reduction of friction on the bottom of the craft. This reduction of friction comes from a very thin layer of air that keeps the craft barely floating. Essentially, it’s air hockey.
Materials
- Old, unwanted compact disk (CD) (1 per hovercraft)
- Flip-top or pop-up spout from a water bottle (1 per hovercraft)
- Scissors
- Sandpaper
- Round balloon – at least 5-inch size (1 per hovercraft)
- 1 or 2 low-temperature hot glue guns and glue sticks
- Eye protection
- Paper dot stickers
Engage
The first part of this activity is building the hovercrafts themselves. Essentially, a water bottle nozzle is affixed to the hole in the center of a CD disk with hot glue, Then an inflated balloon is stretched over the other side of the nozzle. As the balloon deflates, it releases air through the nozzle and hovers, a simple push gets it shooting across the room
Explain
Building a hovercraft can be all fun and games, but what makes it a STEM activity is the science behind it. Do your students understand what’s going on? Why does it float? What are the forces acting on the system? Have students draw a force diagram. This should help them visualize how they can make improvements to their hovercraft.
Elaborate
Once the hovercrafts have been assembled, and the students have explored their capability, its time for real scientific experimentation. In the explore phase, students should innovate! How do you make the hovercraft travel faster, further? Are there improvements to be made to the balloon, the nozzle? Would a different material work better as the base? Is there some sort of propulsion system that would make it go on its own? This is where the students get to be creative and perfect their hovercrafts (either individually or in groups)
Make it into a competition. Decide what parameters to set and let the students know what kind of test you are going to put their crafts to. Maybe the goal is distance, or speed, or longest continual hover. Carry out the competition, award the winner, and have the students evaluate themselves on their performance.
Evaluate
Have the students draw a force diagram of their hovercraft. They will need to label the forces involved and explain how they either maximized or minimized those forces to achieve a goal.
https://twitter.com/MrPeterMurray/status/1056748268288380928
Credit to the Jet Propulsion Lab at NASA for designing this activity.
https://www.jpl.nasa.gov/edu/teach/activity/hovering-on-a-cushion-of-air/
Peter, I love it! What a unique way to get students to see forces that are not always so obvious. This is far from another cliche science project. I agree with Bryce that other aspects of science could be tied in as well, and perhaps this could mean understanding the materials involved or creating a reaction that creates the force (as a gas expands, perhaps). The force diagram at the end is a great way to be sure the students understand what’s actually happening!
Thanks Will! I think there are definitely some options to play with as far as materials and the gas involved. I thought the force diagram works well as a check to make sure that kids understand what’s happening, but I also think it could also be effective as an assessment for ELLs being that it’s primarily visual.
Amazing post Peter! I really love the idea behind the hovercraft demo, and I think that students would have a blast with it! My question is, could you tie this sort of demo to other concentrations? To me, this seems like a very physics-heavy demo, but could you tie it to something like Chemistry or Biology?
Thanks Bryce! I think its very physics heavy as well. It’s a pretty simple construction so I’m not sure there is much you can do with that, but with the blowing up of the balloon, I certainly think there could be a discussion about gas laws.