Des Lines of Swannanoa, and a few of his aviation friends, have held some science classes for the local school.
One of his demonstrations is to show that air has weight.
The device is pictured here.
The deflated balloon is initially ballanced horizontally by a small counter weight.
Air is then introduced into the balloon and behold - the balloon raises the counter weight.
All magic really.
This is just one of the simple devices that Des has used for these kids.