Harnessing the Nepisiguit Falls: A Hydroelectric Turbine Challenge for Grades 6-8

Overview

Learners use the Nepisiguit station video as a local phenomenon for exploring energy transfer and technological design. Teams construct a model water turbine, develop a fair-test procedure, and investigate how one independent variable affects performance. After analyzing baseline data, they redesign one feature, retest the turbine, and present an evidence-based recommendation. The emphasis is on controlled variables, repeatable measurements, data quality, design iteration, and the limits of models.

In this investigation learners will design and test a model turbine that produces the greatest measurable output using a fixed quantity of water.

NB Curricular Connections

Science

• Strand: Scientific Literacy — Big Idea: Investigation:
  • Grade 6 Skill Descriptor – Plan investigations to answer questions about relationships between and among variables observed in natural and technical sensory systems.
  • Grade 7 Skill Descriptor – Plan investigations to answer questions about relationships between and among variables observed in matter and Earth surface processes.
  • Grade 8 Skill Descriptor – Plan investigations to answer questions about relationships between and among variables observed in motion and stability, the Laws of Motion, and space exploration.
• Strand: Scientific Literacy — Big Idea: Investigation:
  • Grade 6 Skill Descriptor – Collect and represent data using a variety of tools and methods appropriate for investigations of natural and technical sensory systems.
  • Grade 7 Skill Descriptor – Collect and represent data using a variety of tools and methods appropriate for investigations of matter and Earth surface processes.
  • Grade 8 Skill Descriptor – Collect and represent data using a variety of tools and methods appropriate for investigations of motion and stability, the Laws of Motion, and space exploration.
• Strand: Scientific Literacy — Big Idea: Sensemaking
  • Grades 6, 7, 8 – Skill Descriptor – Analyze and interpret qualitative and quantitative data to construct explanations and conclusions.
• Strand: Scientific Literacy — Big Idea: Communication
  • Grades 6, 7, 8 – Skill Descriptor – Communicate procedure, result, and conclusion using a variety of media and working collaboratively.
•  Strand: Learning and Living Sustainably – Big Idea: Responsible and Sustainable Application
  • Grade 6 Skill Descriptor – Apply scientific and technological knowledge and an understanding of sustainable practices responsibly with respect to natural and technical sensory systems.
  • Grade 7 Skill Descriptor – Apply scientific and technological knowledge and an understanding of sustainable practices responsibly with respect to matter and Earth surface processes.
  • Grade 8 Skill Descriptor – Apply scientific and technological knowledge and an understanding of sustainable practices responsibly with respect to motion and stability, the Laws of Motion, and space exploration.

What You’ll Need

• Link to the video on Nepisiguit Falls
• Link to the video on Hydropower 101
• Glue Gun
• Utility Knife or Heavy duty scissors
• Containers of water for refilling measuring cups
• For Learning Groups of 4 or 5
  • Copy of the Engineering Design Investigation Sheet (attached)
  • 1 straight bamboo barbecue skewer, approximately 25 cm long
  • 1 wine cork
  • 6 plastic teaspoons
  • 2 drinking-straw pieces, each approximately 4 cm long
  • 2 tall, sturdy plastic cups, at least 12–14 cm high
  • 1 large plastic dishpan or shallow storage bin
  • 1 rigid plastic lid or piece of corrugated cardboard for a base
  • Duct tape or another water-resistant tape
  • Hot-glue gun and glue sticks
  • Permanent marker
  • Ruler
  • Scissors or wire cutters
  • Awl, small drill bit, or metal skewer
  • Approximately 40 cm of cotton string
  • 3–5 identical paperclips
  • 1 small cup to hold the paperclip load
  • 1 graduated measuring cup
  • Water
  • 1 stopwatch
  • Towels or reusable cloths

Instructions

Preparation Instructions

Build a Model Water Turbine for Demonstration – This model demonstrates how moving water can transfer energy to turbine blades and cause an axle to rotate. It represents the water-to-motion portion of a hydroelectric station; it does not generate electricity. With the required materials this should take 20-30 minutes.

Before Construction

Only the teacher should:

• Use the hot-glue gun
• Make holes in the cork
• Cut plastic spoons
• Cut or blunt the bamboo skewer
• Use sharp or pointed tools

Build and test the model before class. Small differences in spoon size, axle alignment, and cup height can affect performance.

Part 1: Construct the turbine

Step 1: Prepare the axle

1. Select a straight bamboo skewer.
2. Cut it to approximately 25 cm.
3. Remove the pointed end with scissors or wire cutters.
4. Cover both ends with a small piece of tape.
5. Roll the skewer across a flat surface to check that it is straight.

A bent axle will wobble and create unnecessary friction.

Step 2: Prepare the cork hub

1. Mark the centre of each circular end of the cork.
2. Use an awl, drill bit, or metal skewer to make a hole lengthwise through the cork.
3. Keep the hole as straight and centred as possible.
4. Slide the cork onto the skewer.
5. Position it at the centre of the axle.
6. Add a small amount of hot glue where the skewer enters and exits the cork.

The cork and skewer must rotate together. The cork should not spin independently around the axle.

Step 3: Prepare the turbine blades

1. Use six plastic teaspoons of the same size and shape.
2. Shorten each handle so that approximately 3–4 cm of handle remains below the spoon bowl.
3. Mark six evenly spaced positions around the cork.
4. Arrange the spoons around the cork before gluing them.
5. Position every spoon bowl so its concave surface faces the same rotational direction.
6. Hot-glue each shortened handle lengthwise against the cork.
7. Allow the glue to cool completely.
8. Reinforce the handles with narrow strips of duct tape if necessary.

The finished turbine should resemble a wheel with six evenly spaced spoon bowls around its centre.

Step 4: Check the turbine balance

1. Hold the ends of the axle loosely between your fingers.
2. Spin the turbine gently.
3. Watch for wobbling or one side consistently falling downward.
4. Reposition any noticeably uneven blades.
5. Confirm that no loose glue or tape protrudes from the hub.

Perfect balance is unnecessary, but severe imbalance will make comparisons less reliable.

Part 2: Build the support system

Step 5: Make the bearings

1. Cut two pieces of drinking straw, each approximately 4 cm long.
2. Slide one straw piece over each end of the skewer.
3. Hold the straw pieces stationary.
4. Spin the axle inside them.
5. Confirm that the axle turns freely.

The straw pieces act as bearings. They support the axle while reducing friction.

Step 6: Position the supports

1. Turn two tall plastic cups upside down.
2. Place them approximately 15–18 cm apart.
3. Rest the turbine between them.
4. Confirm that the blades have at least 2 cm of clearance above the base.
5. Move the supports closer together if too much axle extends between the cups.
6. Move them farther apart if the turbine blades touch the cups.

Step 7: Attach the bearings

1. Place one straw bearing horizontally across the flat top of each inverted cup.
2. Align the bearings so they point directly toward one another.
3. Tape each straw firmly to its cup.
4. Keep both ends of each straw clear of tape.
5. Spin the turbine again.
6. Adjust the cup positions until the turbine rotates freely.

Misaligned bearings are one of the most common reasons a model turbine fails to turn.

Step 8: Secure the supports

1. Place the cups and turbine inside a large plastic dishpan or storage bin.
2. Tape the inverted cups to a rigid base or directly to the bottom of the bin.
3. Check that the turbine remains level.
4. Confirm that water cannot cause the supports to slide.
5. Place towels around the testing area.

Part 3: Add a measurable mechanical output

Step 9: Attach the lifting string

1. Choose the end of the axle that extends farthest beyond its straw bearing.
2. Tape one end of a 40 cm string securely to the axle.
3. Wind the string around the axle two or three times.
4. Attach one paperclip to the other end.
5. Position a small empty cup below the paperclip.
6. Ensure the string and paperclip do not interfere with the turbine blades.
7. Turn the turbine by hand and confirm that the axle winds the string and lifts the paperclip.

The small cup catches the paperclip if it falls and helps keep the load separate from the water.

Step 10: Mark one blade

Place a small piece of brightly coloured tape on one spoon bowl.

This reference mark allows learners to count turbine rotations.

Part 4: Test the model before class

Step 11: Conduct a dry test

1. Spin the turbine gently by hand.
2. Confirm that it completes several rotations.
3. Check that the blades do not touch the supports or basin.
4. Confirm that the string winds around the axle without tangling.
5. Realign the bearings if the turbine stops immediately.

Step 12: Conduct a water test

1. Measure exactly 250 mL of water.
2. Hold the measuring cup approximately 20–30 cm above the turbine.
3. Pour a narrow, steady stream onto the outer portion of the spoon bowls.
4. Do not pour directly onto the cork or axle.
5. Observe whether the turbine rotates and lifts the paperclip.
6. Dry and adjust the model if necessary.

Pouring water near the outer edge of the turbine produces more turning effect than pouring near the axle.

Lesson Instructions

Phase 1: Observe the real system

1. Before viewing the videos, ask learners to predict the pathway of energy through a hydroelectric station.
2. During the videos, learners identify inputs, processes, outputs, controls, and evidence of engineering or maintenance work.
3. Construct a class energy-transfer model. A useful sequence is gravitational potential energy of elevated water → kinetic energy of moving water → rotational mechanical energy of the turbine and shaft → electrical energy from the generator.

Phase 2: Define the investigation

4. Introduce the engineering brief
   • “Using the same limited quantity of water for every trial, design and test a model turbine that produces the greatest measurable mechanical output.and available materials. Establish common constraints so team results are comparable.”
5. Teams select one independent variable. Suitable choices include water-drop height, blade number, blade surface area, blade angle, or nozzle opening/flow rate.
6. Teams define a dependent variable that can be measured reliably and list the variables they will control.
7. Teams write a hypothesis using an “If…then…because…” structure and prepare a repeatable procedure.

Phase 3: Build and collect baseline data

8. Build the first turbine and perform a low-water trial to check alignment, axle friction, blade contact, and measurement method.
9. Complete at least three baseline trials. Use the same water volume, release method, turbine position, and measurement procedure each time.
10. Record results with units and calculate an appropriate summary, such as the mean. Note anomalies and plausible sources of error.

Phase 4: Redesign and retest

11. Use the baseline evidence to select one design change. Sketch and justify the change before rebuilding.
12. Complete at least three trials of the revised design under the same test conditions.
13. Graph or otherwise represent the baseline and revised data. Compare central tendency, consistency, and percent change where appropriate.

Phase 5: Engineering recommendation

14. Prepare a concise recommendation containing the design decision, evidence, scientific reasoning, and one limitation.
15. Explain which parts of the classroom model represent the Nepisiguit station and which important features are missing or simplified.
16. Identify a further question that could be investigated with more time or different equipment.

Assessment Opportunities

• Product: Engineering Design Investigation Sheet.
• Observation: safe tool use, collaboration, contribution to planning, and careful testing.
• Explanation: a claim supported by evidence from the team’s tests.

Extension Ideas

• Repeat the experiment where students must manipulate a measurable quantity (i.e. flow rate, turbine rotations, etc.) and have them graph their results.
• Use this activity as a baseline to construct their own investigation for science fair.
• Consider using the Wind Energy Challenge for Middle School as an extenion.

Make Meaning

Please see the attached PDF for several choices on how you and your learners can reflect upon today’s activity  

Global Competencies

• Critical Thinking and Problem Solving
• Collaboration
• Global Citizenship and Sustainability

Acknowledgements

NB Power: Learn About Hydroelectricity

NB Power: Nepisiguit Hydroelectric Station video