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In this laboratory experiment, students will become familiar with calculating gravitational potential energy using a hydroelectric turbine. They will also calculate efficiency of such systems and compare it to systems built in previous lab experiments. Students will learn how to plot graphs showing Power vs. Time.

Hydroelectric power plants convert kinetic energy of moving water into electrical energy. A typical scenario is a hydroelectric power plant installed in combination with a river dam. The dam raises the water level in the reservoir. As water from the reservoir is allowed to fall through the pipes, its potential energy is converted into kinetic energy which in turn is used to power a turbine. The turbine converts the kinetic energy into mechanical energy. A generated finally converts the mechanical into electrical energy. Hydroelectric power plants reach efficiencies of up to 80-90%.


  1. Please watch the video below and follow along.

  2. Measure the mass of the water
    (massbeaker+water-massbeaker) = masswater
    Massbeaker = kg

    Massbeaker+water = kg

    Masswater = kg

  3. Please watch the video below and follow along.

  4. Make a Voltage vs. Time graph. Provide the (X,Y) coordinates below.

    Voltage (V)

    Time (seconds)

  5. If Power = (Voltage)2 / Resistance, estimate and draw your Power vs. Time plot. Provide the (X,Y) coordinates below.



  6. J

  7. Determine the average height that the water falls.

    htop = m

    hbottom = m

    hnozzle = m

    havg. = m

  8. PE = Joules

  9. Efficiency = %

  10. Empty beaker.

  11. Lower the position of the water reservoir to half of the original height.
    Note: be careful not to change the nozzle angle.

  12. Add water to the reservoir.

  13. Measure the mass of the water.
    massbeaker+water - massbeaker = masswater
    Massbeaker = kg

    Massbeaker+water = kg

    Masswater = kg

  14. Please watch the video below and follow along.

  15. In LabView, click the start button.

  16. Open the clamp and allow water to run through the turbine.
    Note: make sure the impeller is rotating.

  17. In LabView, click the stop button.

  18. Power (mW)

    Time (seconds)

  19. Determine the average height that water falls.
    1. htop = m

    2. hbottom = m

    3. hnozzle = m
    4. havg. = m

Thank you for participating in this laboratory experiment.

Please answer the following questions. Your answers will not be graded.

This laboratory experiment procedure may contain parts of various PASCO Accessory Manuals which are copyrighted and reserve all their rights.
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