The children were given a pre-made catapult and were asked if they thought they could build their own.
After a discussion about how the example was made they set out to create their own.
With different levels of assistance every child was able to assemble a working catapult.
The interesting occurrence was that they figured out on their own that there were different ways to build them.
One catapult you pull the end of the stick back to "launch" the aluminum foil ball into the air, another way required the child to bang the end with their fist. It all depended on the way the craft stick was mounted on the clothes pin.
When construction was finished they decorated them or just set off into the red room to give them a try.