Balloon car and rocket

Monday, October 6th, 2008
We are talking about forces, about air in particular.
First we tried to fly a balloon straight to teacher. It was impossible. Lots of people tried to do it.
Next, teacher showed us her balloon car. We had to guess which way the car would move when the air was let out of the balloon. We discovered that the car moves in the opposite direction from the way the air escapes.
What we really wanted to do was to make a balloon fly straight to teacher. We tried taping the balloon to a piece of string but that didn't work. The balloon couldn't fly, it just spun round and round the piece of string. Finally we discovered that if we taped the balloon to a straw and put the string inside the straw, that the balloon would fly straight along the string. We even discovered that the balloon could fly uphill and downhill, just by having the string held at different heights. It was a very exciting investigation.