Teacher Notes

Build a Water Wheel

Flinn STEM Design Challenge™

Materials Included In Kit

Aluminum dishes, 40
Binder clips, 4
Caps with ½" hole, 10
Cups, 30-mL, 40
Hex nuts, 20
O-rings, 4
Paper clips, jumbo, 2
Plastic pans, 2
Pipets, super jumbo, 40
Rubber tubes, 1", 2
Tape, masking, 3 rolls
Weighing dishes, small, 40
Wood dowel rods, 12" x ¼" diameter, 2

Additional Materials Required

Glue gun and glue sticks (optional)*
Marker, permanent†
Meter stick†
Source of running water† (see Lab Hints section)
Stopwatch or timer*
*for each lab group
for Prelab Preparation

Prelab Preparation

Enough materials are provided to set up two testing stations.

  1. Fasten a binder clip to the center of each long side of the plastic pan. Flip down the outside metal arm and flip up the inside metal arm of each clip (see Figure 4).
    {14057_Preparation_Figure_4_Side view}
  2. Insert wooden dowel rod into one of the flipped up binder clip arms.
  3. Insert the other end of the dowel rod into the 1-inch rubber tube. Push the tube along the rod until the tube is in the center of the rod.
  4. Insert the rod into the other binder clip arm. The rod should rest on the narrow portion of the binder clip arms (see Figure 5).
  5. Cut a 65-cm length of string.
  6. Tie a large knot at one end of the string and thread the knot through one of the O-rings.
  7. Making sure the knot remains threaded through the O-ring, place the ring onto the dowel rod, 1.5 cm from the end.
  8. Place a second O-ring at the very end of the dowel rod (see Figure 6).
  9. Tie the free end of the string to a paper clip.
  10. From the top of the paper clip, measure 50 cm along the string and mark this length on the string with a permanent marker.
  11. Pull the knotted end of the string that is through the O-ring until the 50-cm mark is at the bottom of the dowel rod, so from the dowel rod to the paper clip measures 50 cm (see Figure 7).
  12. Set the pan with the dowel rod along the edge of a lab counter or table so the paper clip hangs down freely and the string does not rub against anything when the load is lifted during testing.
  13. Repeat steps 1–12 for a second testing station.
  14. Weigh ten hex nuts on a balance to determine the average weight of each nut. Write the average weight in N on a notecard and post by each testing station. Note: 1 g = 0.0098 N. For a simplification, multiply the amount in grams by 0.01 for an approximate conversion to newtons.
  15. Attach 5 hex nuts to the paper clip hanging from each dowel rod. Pinch the paper clip closed to secure the hex nuts.
  16. The string should wind up between the two O-rings during testing.
  17. For testing the final water wheel designs in Part B, add five more hex nuts to each paper clip for a total of 10.

Safety Precautions

Remind students to use caution when cutting with scissors. Wear safety glasses during testing. If testing indoors, wipe up all water spills immediately. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory.

Lab Hints

  • Enough materials are provided in this kit for 30 students working in groups of three or for 10 groups of students. Both parts of this laboratory activity can reasonably be completed in two 50-minute class periods. The pre-laboratory assignment may be completed before coming to lab, and the data compilation and calculations may be completed the day after the lab.
  • To optimize a fair test, the running water must have a consistent flow rate. A few suggestions are given.
    • If a lab sink has a serrated nozzle, attach plastic tubing to the nozzle. Hold the end of the tubing a set distance over the water wheel and find a good setting on the faucet for a steady flow of water that is not too forceful. Mark this setting with tape.
    • Set up a support stand with a ring clamp and place a funnel in the ring. Fill a large pitcher or water jug (2-4 L). Stopper the funnel stem and fill the funnel with water. At the same time the stopper is removed, pour water steadily into the top of the funnel so the water level in the funnel remains constant.
    • Challenge your students to come up with a way to ensure a consistent flow of water. Let their creativity flow!
  • For indoor testing, place a large towel or tray such under the plastic pan to contain splashes of water. A large demonstration tray is available from Flinn Scientific, Catalog No. AP5429. If any water splashes onto the floor, wipe up immediately.
  • Start each test with five hex nuts for the load. Adjust the load if none of the prototypes can lift it or if all raise the load very fast. For the final test, use 10 hex nuts at each station. Additional weights or standard hanging weights may be used to determine the maximum load a water wheel can lift.
  • The water wheel prototype is constructed without glue to allow ease of modifications. Once students have chosen their final design, you may decide to allow the use of glue. Hot glue or other water-proof adhesive for binding plastic to plastic should be used. Consider the experience and maturity of your students and set specific design constraints accordingly.

Teacher Tips

  • This activity may be used in conjunction with a unit on engineering design, transfer of energy or renewable resources. Students should have prior knowledge of types of energy such as mechanical, kinetic and gravitational potential.
  • More advanced students can research the Pelton wheel, designed to make maximum use of the impulse (change in momentum) of the moving water. Challenge students to design a Pelton wheel and compare its power output to the original prototype.
  • Students may further research hydropower as it is used today, particularly hydroelectric power.

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Asking questions and defining problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluation, and communicating information

Disciplinary Core Ideas

MS-ETS1.A: Defining and Delimiting Engineering Problems
MS-ETS1.B: Developing Possible Solutions
MS-ETS1.C: Optimizing the Design Solution
HS-PS3.B: Conservation of Energy and Energy Transfer

Crosscutting Concepts

Cause and effect
Scale, proportion, and quantity
Systems and system models
Structure and function

Performance Expectations

MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
HS-PS3-2. Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motion of particles (objects) and energy associated with the relative position of particles (objects).
HS-PS3-3. Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.

Answers to Prelab Questions

  1. Why is water considered a renewable source of energy?

    The amount of water on the Earth and its atmosphere is constant. Using water to power a water wheel does not reduce the amount of water available.

  2. A student lifted a backpack weighing 80 N to a desktop that was 0.76 m high. How much work did the student do?

    Work = 80 N x 0.76 m = 60.8 J

  3. Two students volunteered in the library. They were assigned the task of lifting books from a cart to a shelf. Each book weighed 10 N. Kayla’s shelf was 1 meter above the cart and she shelved 20 books in one minute. Noah’s shelf was 0.5 m above the cart and he shelved 48 books in 90 seconds. Who generated more power in shelving the books? Show your work.

    Kayla: Force = 10 N x 20 = 200 N

    Work = 200 N x 1 m = 200 J
    Power = 200 J/60 s = 3.33 W

    Noah: Force = 10 N x 48 = 480 N

    Work = 480 N x 0.5 m = 240 J
    Power = 240 J/90 s = 2.67 W

    Kayla produced more power than Noah.

Sample Data

Part A. Build a Model Water Wheel

Write a description or draw and label the chosen water wheel design.

Removed stems from pipets and cut across each bulb to make a 2-cm diameter bucket that was 2.5 cm deep. Arranged seven buckets around wheel, fairly evenly spaced. The sides of the bulbs were pressed onto the tape around the wheel.

Data Table A. Weight of load: ___0.14___N Distance lifted: ___0.5___m

Part B. Design Challenge

Write a description or draw and label the chosen water wheel design.

The pipet-bulb buckets were cut in half lengthwise to form a scoop. Pressed the rounded end of each bucket onto the tape around the wheel so the open end of the scoop faced away from the wheel. Used 8 buckets very evenly spaced around wheel.

Data Table B. Weight of load: ___0.28___N Distance lifted: ___0.5___m

Answers to Questions

  1. Calculate the work done by the modified water wheel from Part B and record in Data Table B.

    Work = F x D
    W = 0.28 N x 0.5 m = 0.14 J

  2. Calculate the power generated by the modified water wheel for each trial and the average power output. Fill in the data table.

    Power = Work/Time
    P = 0.14 J/8.45 s = 0.018 W

  3. How did the amount of power generated by the original water wheel design compare to the modified design?

    The modified design generated over 3.5 times as much power as the original design. It not only lifted more weight, it did so in less time.

  4. Describe how energy is transferred throughout the water wheel system, starting with energy from the Sun and ending with the lifted load.

    Energy from the Sun drives the water cycle of evaporation, condensation and precipitation. Gravity causes water on the Earth to flow. The kinetic energy of the moving water fills a bucket on the wheel, and the turning wheel gains kinetic energy. As the wheel turns, the next bucket fills with water, and so on. When the filled buckets reach the bottom of the turning wheel, the water empties and the buckets continue up the other side, to be filled again. The mechanical energy of the turning wheel is transferred to the dowel rod, causing it to spin. The spinning rod winds up the string and lifts the load. The load has kinetic energy as it is being lifted, and ends with gravitational potential energy when it stops at the rod.

  5. The largest water wheel in the world, called the Laxey Wheel, measures 22.1 m in diameter and is 1.8 m wide. It was used to pump water out of underground mines on the Isle of Man. The water wheel could move a volume of water weighing 10,780 N a distance of 640 meters in one minute.
    1. How much work in joules was the wheel capable of producing?

      Work = 10,780 N x 640 m = 6,899,200 J

    2. How much power could the Laxey Wheel produce? (Reminder: Power is the rate of work done per second).

      Power = 6,899,200 J/60 s = 114,987 W


Hydropower. Secondary Energy Infobook. National Energy Education Development Project. http://www.need.org/files/curriculum/guides/Secondary%20Energy%20Infobook.pdf (accessed January 2016).

Student Pages

Build a Water Wheel


Hydropower has been used to do work for thousands of years. Water wheels transfer the energy of flowing water to mechanical energy to press, grind, crush, lift and saw. Build a water wheel and determine how much power the wheel can generate!


  • Water cycle
  • Energy transfer
  • Hydropower
  • Work and power


Mechanical energy from the force of flowing water is known as hydropower. Considered a renewable source of energy, hydropower originates with energy from the Sun. This energy causes water on the Earth to evaporate and rise upward as water vapor. The vapor then cools and condenses, eventually returning to Earth as precipitation. This continuous movement of water through evaporation, condensation and precipitation is known as the water cycle. The amount of water on the Earth, including its atmosphere, remains constant.

Gravity causes the water in lakes, rivers and streams to flow downward. A water wheel is a large rotating wheel with buckets that capture the water as it flows over the wheel. As a bucket fills with water, it increases in weight. The greater weight on one side of the wheel causes it to turn, gaining kinetic energy. In this way the wheel acts like a lever. Think of a seesaw where the person on one side is heavier than the person on the other. The seesaw will tip downward on the side with more weight. As the wheel turns, the next bucket fills with water, continuing the rotation of the wheel. When a bucket nears the bottom of the wheel, the water empties into the stream, so the buckets on the upward turning side of the wheel weigh less than those on the downward side. As long as the water flows, the wheel will turn.

The axle of the water wheel can be attached to other machinery to transfer the wheel’s mechanical energy into useful work such as grinding grain into flour or wood into pulp to make paper, hammering metal or pounding fibers, and crushing ore. Work is defined as the amount of force (measured in newtons) exerted over a distance (meters) and can be calculated using Equation 1. The unit of work is the joule (J).

The faster a water wheel does work, the more power it produces. Power is the rate at which work is done and is measured in watts (W)—one watt is equal to one joule of work per second, as shown in Equation 2.

Experiment Overview

The purpose of this activity is to build a model water wheel prototype. The wheel will be used to raise a load and the amount of work done and power generated will be calculated. Improvements will then be made to the wheel to increase the amount of power produced.


Aluminum dishes*
Cap with center hole
Cups, plastic, 30-mL*
Masking tape
Spring scale
Weighing dishes*
*Bucket material choices

Prelab Questions

  1. Why is water considered a renewable source of energy?
  2. A student lifted a backpack weighing 80 N to a desktop that was 0.76 m high. How much work did the student do?
  3. Two students volunteered in the library. They were assigned the task of lifting books from a cart to a shelf. Each book weighed 10 N. Kayla’s shelf was 1 meter above the cart and she shelved 20 books in one minute. Noah’s shelf was 0.5 m above the cart and he shelved 48 books in 90 seconds. Who generated more power in shelving the books? Show your work.

Safety Precautions

Use caution when cutting with scissors. Wear safety glasses during testing. Wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.


Part A. Build a Model Water Wheel Prototype

  1. Read through the entire procedure before beginning.
  2. Take 510 minutes to plan the bucket design for the water wheel. Each bucket on the wheel must be made from the same material, chosen from those provided.
  3. Consider the following questions when planning the design.
    1. Which item will be chosen for the buckets?
    2. How many buckets will be attached to the wheel? Note: A maximum of eight may be used for the prototype.
    3. Will the item chosen for the buckets be modified in any way?
  4. Once the group has determined the bucket design, obtain the following materials from the instructor: bucket material, cap with a center hole, masking tape and scissors.
  5. Cut a piece of masking tape that is 3–4 cm longer than the circumference of the wheel.
  6. Press 1 cm of the tape onto the wheel circumference.
  7. Fold the masking tape back so it doubles over the 1 cm of tape and the sticky side is now facing out (see Figure 1).
  8. Tightly wrap the tape around the circumference of the cap, sticky side out and overlap the tape by 1 cm (see Figure 2).
  9. If desired, use scissors to modify the buckets.
  10. Press each bucket firmly onto the tape around the wheel (see Figure 3).
  11. Write a description or draw and label a diagram of your group’s water wheel prototype for Part A on the Build a Water Wheel worksheet.
  12. Take your water wheel to the testing station.
  13. Attach the water wheel to the axle by threading one end of the dowel rod through the hole in the cap, making sure the buckets are facing the correct way. Move the cap to the center of the dowel rod so the hole fits snugly onto the center of the rubber tube on the dowel.
  14. Make sure the attached string is 0.5 m long from the dowel rod to the top of the paper clip and that the string is hanging freely.
  15. Calculate the weight of the load by multiplying the weight of one hex nut as given by the instructor times the number of hex nuts to be lifted with the water wheel prototype. Record the weight of the load in N and the distance the load will be lifted in meters above Data Table A on the worksheet.
  16. One person should start the timer when another person starts the water flowing. Stop the timer when the top of the paper clip holding the load of hex nuts reaches the dowel rod.
  17. Record the time in seconds that it took to lift the load on the worksheet.
  18. Unwind the string to the 0.5 m mark and repeat steps 16–17 for a second trial.
  19. Remove the wheel from the dowel rod, making sure the rubber tube stays centered on the rod.
  20. Complete Data Table A by calculating the work done and power output for each trial and the average power output for the water wheel model.
Part B. Design Challenge

The challenge is to make improvements to the water wheel in order to lift a load of 10 hex nuts in the fastest time. The power output will be calculated in watts.
  1. Consider the following as you redesign the water wheel.
    1. Was the water wheel well balanced and did it spin smoothly?
    2. Could the shape or size of the bucket be modified in any way to improve the efficiency of the wheel?
    3. What effect might adding buckets have on the performance of the wheel?
    4. What effect might removing buckets have on the performance of the wheel?
  2. Once the modified wheel is complete, take it to a testing station.
  3. Record the mass of the 10 hex nuts and the distance they will be lifted above Data Table B on the worksheet.
  4. Run two trials the same way as in Part A with the increased load.
  5. Complete Data Table B on the worksheet and answer the Postlab Questions.
  6. Consult your instructor for appropriate disposal procedures.

Student Worksheet PDF


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