Dr Rhys Morgan, a member of the Royal Academy of Engineering, has come up with a formula to help you choose the perfect stick for the popular British game of poohsticks.
(The formula is - PP = A x ? x Cd
- PP = the perfect poohstick
- A = the cross section area (the thicker the better)
- ? = the sticks density (the denser the better)
- Cd = the drag coefficient describing the shape and roughness (the rougher the better)