We are learning a lot about air.
We were wondering if it is possible to blow a light ball out of a funnel, and whether the size of the funnel would make this task easier or more difficult?
Of course we tried this to find out.
But first, of course, we made our predictions.
This time we had to take account of gravity which is trying to pull the ball down to the ground.
Some of us predicted that of course, with a big enough blow, we can get the ball to pop out of the funnel. Others predicted that the air we blow in to the funnel would stay at the sides of the funnel. This air would be moving very quickly while the air on top of the ball would be still, and make the ball press down into the funnel. In fact we found that although the ball spun around, it never did pop out of the funnel, no matter how hard we were able to blow, or how big or small the funnel is.
Now, here's something really interesting. What happens if you turn the funnel upside down, keep the ball in the funnel with your finger, blow hard and then take your finger away?
With small funnels this is spectacular!
Why do you think this happens? Now that we have learned lots about air we realise that when we blow into the funnel, our air moves quickly. The air under the ball is moving only slowly, so it pushes the ball up into the funnel. When we run out of blow, the air in the funnel is the same as the air under the ball, and then gravity pulls the ball to the ground.
Science is SO interesting!