Milk carton water wheel

Ever held a toy under your running bath water? Did it spin or twist away from you? This is explained by a law proposed by a guy named Sir Isaac Newton. Specifically the law states that ‘for every action there is a equal and opposite reaction’. You know, kind of like when you smack your big brother you know you’re going to get smacked back. OK, so maybe that’s not such a great example. Here’s one that will aptly demonstrate Newton’s law.

1. Poke a hole in the bottom left hand corner of each of the four faces of a half-gallon, paper milk carton.
2. Now poke a hole in the top flap of the milk carton. Tie a string through this hole.
3. While covering the holes in the milk carton, pour water into the carton (unless you have more than 2 hands, you may need some assistance with this step).
4. Suspend the carton in the air by holding on to the string only.
5. Now take your fingers off of the holes (did we mention that this should be done outside or over a sink – oh well, too late now).

Newton’s Third Law states that every action has an equal and opposite reaction. Water shoots out the holes, and pushes back on the carton with equal force. A turbine is formed as the energy of the moving liquid is converted into rotational energy.