The wind bag

Wind bags are long blue bags, that we used to experiment with. We blew into it with five big breaths trying to fill it up. We used two techniques to blow the wind bag up. The first is blowing into it from close up inside the wind bag and the second one was blowing into it from a distance ( 30 cm etc). We experienced that when we blow up the wind bag closer up doesn’t get as much air than you would 30 cm back, because when you are about 30 cm back 10 x of the of air is coming in than your one breath. That is because when you blow air in that air is under pressure. Then other air comes from behind and also goes into the bag.

By Callum and Becky.

The hot air balloon

The hot air balloon was made out of a big plastic bag ,tape, wire and a tin. It works by cotton wool, metholated spirits and matches. The first time we flew it, it went really high and then the same day but the second time it didn’t work because there was a big hole in the bag. After we flew it once the can turned purple. A few days later we repaired the balloon with tape and we put the can down further because we thought that it would produce more air to go in the
balloon. That did not happen because the time that we went out it was to windy that the hot air was not all going in the balloon.

Luke and Callum

Solar Bag experiment

We went down to the field with a solar bag. We ran around with it and filled the bag with air. When the sun heated it up it rose up into the air.
This happened because when the sun heats up the air it gets less dense. This means it's lighter and so it floats on the colder air.
We saw that when the sun went in, the bag came back down to earth. This is because the air cooled and became less dense.
Next time we'll try an air balloon and see what happens.