The children were required to research birds and their habitats, find out what birds don't like and include this research in their solution. They found out that birds easily get used to the same noise, so developed a device in which ball bearings hit a musical steel drum making different sounds in different parts of the drum. They chose a snail cam as this would turn slowly then release the ball bearings quickly. A series of springs was added to give more power. To ensure the ball bearings would roll back ready to be fired again, the girls added a funnel, which in this case was the end of a tenor horn.
The mechanism was not powerful enough to fire the ball bearings with force, but when the machine was turned over for final adjustments, the girls found that it makes a very good thudding noise against the floor www.youngeng.org
Carolyn Bryan teaches at Uplands Junior School, Wolverhampton