Creeping into the long lost tomb which contains the Inca treasure, you step on a broken stone slab - and a giant balls starts rolling down the tunnel towards you! What do you do next?
Levels of difficulty:
Level 1 - Build a small cage which is not crushed or broken by the rolling ball Level 2 - As level 1, and which is big enough for a child to crouch down inside Level 3 - As level 2, and the shape of the cage makes the ball roll over the top and down the other side
Equipment: KNEX set, plus a giant inflatable ball, and a slope down which the ball can roll.
Approach: How can you make a cage that will provide protection against a giant rolling ball? What shape will it be? How can you make it very strong? For level 2, how are you going to fit inside the ball - sitting, lying, crouching? What construction method can you use which wont break when the ball hits the cage? For level 3, what shape should you make the cage so that the ball rolls over it?
An enjoyable project which necessitates careful consideration of how to build a strong and stable structure.
Possible solution: See photo.
Before starting: Show the children how the ball rolls down the slope.
Conclusion: If possible, test the cages on differing slopes, and ask the children to consider what factors determine whether the cage breaks or not (strength of cage, angle of slope, amount of bounce on ball, etc).