Get the latest tech news

Coke can planimeter

coke can planimeter A planimeter measures area; this is one made from a soft drink can. The pointer projecting horizontally from the right-hand end of the can is moved round the shape to be measured, the total rotation of the can is proportional to the area.

The pointer projecting horizontally from the right-hand end of the can is moved round the shape to be measured, the total rotation of the can is proportional to the area. Only one end of the can touches the paper, I found it works better if you put PTFE tape round this bit of the can. It could be made more sophisticated by sticking a spiral paper scale to the can, so that the amount of rotation could be read, rather than just showing that different shapes had the same area.

Get the Android app