STEM – Balloon Hovercrafts

During my STEM hour this week my group did a bit of unplugged making. We had a go at building a constant Pinterest favourite, the balloon hovercraft!

Equipment needed:

  1. Balloons (Obviously!!), make sure you have spares too!
  2. Old Cd’s
  3. Blu Tak, of a glue gun for older pupils.
  4. The cap from a sports bottle (Not the Lucazade Sport ones)
  5. A smooth floor to test an experiment on

BALLOON-CD-ZIPPING-BY

This is a great one from a STEM lesson as it starts off as a little maker project, but then as they complete it and they start to experiment, it turns itself into a science activity. Using on 4 items, the make was quick and simple, yet it challenged the thinking of the pupils. I don’t really think it needs too many instructions. Stick the cap on the CD, making sure it’s air tight, blow the balloon up and stick it on top of the cap. Let the balloon go, and give the CD a little push, and watch as it glides!

A lot of the versions I’ve seen of this online involve hot glue gunning the sports cap to the CD. Just for ease, and a bit of H&S, we used BluTak instead. It worked just as well, and it actually gave us the opportunity for some more maths as the kids had to get their tak sausage to the right circumference before sticking the bottle cap down.

As the children completed their builds we moved on to doing some experiments and thought about how the science worked. We talked about how the air was being pushed under the disc, and how it was creating an air cushion for the whole thing to glide on. This image really helped for explaining it:

Image result for cd hovercraftFor the experiments we took them to the hall and started by letting them glide as far as possible, and tracking results. This brought out some great discussion from the kids, talking about how our tests weren’t fair, and how there were too many variables. We made a few small changes to create a fairer experiment. They tried to think about theur start lines, balloon sizes, and trying to get a regular pushing method. The kids knew they were never going to be totally fair though, but really had a good go at it. This is where teacher mode kicked in for me, and I got the most from the hour. They were actually enjoying recording their results in their books, and wanting to make sure their work was presented as a fair experiment. A rarely seen phenomenon!

For their last step in the hour they added some creativity to the learning. Thinking about designs and paint jobs for their CDs. Obviously a CD with racing flames on the side will go faster and further!! As a follow-up lesson I’ve thought about getting the kids to 3D print a different nozzle to see how they might have different effects. Challenging, but do-able I think!

Above all, this was a really fun hour to spend with the kids. they really enjoyed it, and we had a right laugh. Science for enjoyment instead of ticking boxes can be a wonderful thing!

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