As part of our topic of Flight we are looking at different types of forces

As part of our topic of Flight we are looking at different types of forces.  We are looking at the forces related to an aeroplane flying in the sky.  Before we can understand these forces we had to find out what was meant by air pressure.  To understand air pressure we carried out an experiment using a plastic bottle and a small paper ball.  We had to predict what we thought would happen the paper ball when we blew into the bottle.