A water based puzzle. The classic three cups of different sizes.
1 x 800 ml container full of water
1 x 500 ml container
1 x 300 ml container
1 x measuring jug
1 x funnel if required (to avoid spillage)
A source of spare water.
Provide the cubs with the three containers (with the 800 ml one full) and the instructions attached.
Split the Cubs into their sixes or pairs. Give each pair/six 5 minutes to solve the problem. They get points for solving it, solving it quickly and how accurate they are on the measurements.