Balloon Experiment

Lesson 4 – 12/1/2007

Today we had great fun experimenting with balloons to investigate what makes them move and which type moves fastest.

To start with, we saw that a plastic shopping bag filled with air doesn’t fly around the room, but an untied balloon does.  After a group discussion we decided it was because the force of air created by the stretch of the elastic balloon sides pushed the balloon through the air.

We came up with an experiment to find out if there was a difference in speed between long thin balloons and round ones. We blew up the balloons (although some of us had more puff than others – Mr Cain had a lot of hot air!), stuck them to a straw and fed the straw onto one end of a piece of string.  Some of us used stopwatches to time balloons while others  had a race between the two types of balloon.

Our experiments showed that the long thin balloons travelled fastest.  In our discussion afterwards we decided this was probably because of the more stream-lined shape.

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To day we where figure out which balloon went the fastest. Long balloons or round balloons.   Isla

We found that air is pushed out the balloon to make it move   Nicole.

Long  balloons went fastest because  it  is  streamlined. Johnny.

I had fun learning about air. Miriam

I had fun working out what to do.    Robert P

I liked sticking the straw on the balloon.   Aaron

2 Replies to “Balloon Experiment”

  1. This was a great experiment – you’re real scientists now!

    I like the way you’ve done two different experiments to find out the answer – racing the balloons and timing them with stopwatches. Real scientists often do that to make extra sure of their results.

    Scientists also publish what they have done. That lets others do the experiment for themselves if they want, to check the results. By publishing your experiment on the web, you’ve made it possible for others to try it for themselves. I wonder if anyone will do that? If they do, I hope they let you know!

    Have you noticed that if you push against something it seems to push back? Maybe your teacher will let you try it with the classroom wall, or maybe each other! When you push the wall, it pushes back with the same force. This was discovered by a scientist called Isaac Newton, who called it his 3rd Law. He said, “Every action has an equal and opposite reaction.”

    This is what’s happening with your balloon. When the jet of air from the balloon pushes against the rest of the air in the room, the air pushes back against the jet! Because the balloon isn’t fixed, it starts to move.

    You might have felt this sort of thing if you’ve ever pointed the jet of a hose at something solid, like a car. Have you tried that? How does it feel?

    Mr Gilmour
    (Science teacher)

  2. Jonathan Harding

    I was very exited on that day. when we were doing
    the experiment we had 3 goes 2 of them didnt work
    but 1 of them did WORK.

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