Energy is everywhere, but understanding how energy works can be tricky for kids. Luckily, it's easy to demonstrate the concepts of potential, kinetic, and mechanical energy at home with a simple cone-and-carton water experiment. Learning how to make a water wheel is a great way to make physics come alive for your child, and just might spark a lifelong fascination with science.
What You Do:
- Stretch a rubber band around your oatmeal container 2" from the bottom. Mark a cut line by poking holes in the container all the way around, following the rubber band. Have your child cut the container following the holes. Place the lid on the bottom piece and discard the top piece.
- Next, cover the carton with duct tape. The easiest way to do this is to first cover the bottom and lid, then wrap a single long strip of tape around the body. Rather than cover the bottom one strip at a time, try laying strips of tape sticky-side up on the table, attaching them by overlapping them slightly, then carefully press the carton onto them, pressing any overlapping ends up the side. Repeat for the top (lid) side.
- Cut the scoops by helping your child cut away the edges from 3-4 plastic lids to make them flat. Fold each plastic round in half, then cut along the fold to yield 6-8 half-circles.
- Turn the half-circles into scoops by rolling them into cones and securing with a strip of tape, making sure there aren't any gaps. Rolling takes a little practice; it may be easiest to have your child tape while you hold the sides together.
- Attach the scoops to the side of the carton by laying each scoop against the carton and placing a 1" strip of tape over the lip. Place another strip of tape around the body of the scoop to secure. Repeat until all the scoops have been attached.
- Create holes in the carton for the axle by piercing the lid and bottom of the carton with scissors, centering the holes as well as you can. Have your child widen the hole with her fingers, then insert the wooden dowel and test the spin. The hole should be just big enough to let the wheel spin freely.
- Try out your water wheel by balancing it over a sink or tub, laying the axle ends on either edge. Move the wheel under the faucet. Turn on the tap to just a weak dribble, and adjust the position of the wheel until the water fills the scoops. Watch the wheel begin to turn!
- Encourage your child to play with the wheel, experimenting with high and low water pressure, scoop direction, and wheel position.
A wheel doesn't have to be round. Windmills, pinwheels, and helicopter blades are different kinds of "wheels" on axles. More examples of this simple machine are bicycles, rolling pins, rotary fans, DVD players, and even pencil sharpeners. Play "I Spy" together and see how many you can find!
Did You Know?
The wheel and axle is one of the first "simple machines" man used to harness nature's power. The wheel holds potential energy (untapped energy that is stored). The water holds kinetic energy (energy due to motion). When water and wheel meet, the water applies force on the wheel, causing it to turn and generating mechanical energy. Water wheels have been used for centuries to generate electricity.