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H2O on the Go

Power up with water!

Water power is based on water at a higher level having more “potential energy” (stored energy) than water at a lower level.

When flowing from a high to a low level, water gives up some potential energy. This changes to “kinetic energy” (energy of motion) as the water falls. Moving water can turn a bladed wheel, transforming the kinetic energy into mechanical energy.

In the past, mechanical energy from water wheels was used to grind grain and saw timber. Today moving water is used primarily in generating electric power, called hydroelectric power. Power plants are built at the foot of high dams. Powerful jets of water shoot through pipes from a reservoir. The water hits the blades of dozens of water wheels which turn electric generators.


  • Describe how water wheels can be used to generate energy.


  • Per Group:
    aluminum foil pie plate
    piece of string about 45 cm long
    nut from a bolt (or other small weight)
    water source (e.g. faucet or hose)

Key Questions

  • Can you make the wheel move faster?
  • How much weight can the wheel lift?
  • What is potential energy?
  • What is kinetic energy?

What To Do

  1. Cut out the circular bottom of an aluminum foil pie plate. Make eight equally spaced cuts toward the centre of the foil circle. End each cut about 2 cm from the centre.
  2. Use a ruler to fold one edge of each section of the plate to make small ledges.
  3. Punch a hole in the centre of the plate and push a pencil through it. The pencil should fit snugly in the hole; secure the pencil in place with tape.
  4. Hold the wheel under a slow stream of water (e.g. garden hose or kitchen faucet) so that water hits the blades. Let the ends of the pencil rest lightly between your thumbs and index fingers. The wheel should turn smoothly.
  5. Increase and reduce the flow of water. What happens to the wheel?
  6. Tie one end of a piece of string to the pencil and attach a weight to the other end. The water wheel should wind the string onto the pencil, lifting the weight.


  • What is the environmental impact of dams and electricity generation on streams and rivers?