How efficiently can you pack together disks?
How would you design the tiering of seats in a stadium so that all spectators have a good view?
Build a scaffold out of drinking-straws to support a cup of water
Design and construct a prototype intercooler which will satisfy agreed quality control constraints.
A simple robot to make, plus robots in everyday life to investigate.
What shape and size of drinks mat is best for flipping and catching?
Design and test a paper helicopter. What is the best design?