Students learn how engineers design devices that use water to generate electricity by building model water turbines and measuring the resulting current produced in a motor. Students work through the engineering design process to build the turbines, analyze the performance of their turbines and make calculations to determine the most suitable locations to build dams.
Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standard Network (ASN), a project of JES & Co. (www.jesandco.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.
Click on the standard groupings to explore this hierarchy as it applies to this document.
- Colorado: Math
- a. Represent, solve, and interpret problems in various contexts using linear, quadratic, and exponential functions (Grades 9 - 12)  ...show
- Colorado: Science
- a. Develop, communicate, and justify an evidence-based scientific explanation regarding the potential and kinetic nature of mechanical energy (Grades 9 - 12)  ...show
- b. Use appropriate measurements, equations and graphs to gather, analyze, and interpret data on the quantity of energy in a system or an object (Grades 9 - 12)  ...show
- Common Core State Standards for Mathematics: Math
- 1. Use units as a way to understand problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays. (Grades 9 - 12)  ...show
- 4. Rearrange formulas to highlight a quantity of interest, using the same reasoning as in solving equations. For example, rearrange Ohm's law V = IR to highlight resistance R. (Grades 9 - 12)  ...show
- 2. Solve simple rational and radical equations in one variable, and give examples showing how extraneous solutions may arise. (Grades 9 - 12)  ...show
- 3. Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters. (Grades 9 - 12)  ...show
- b. Solve quadratic equations by inspection (e.g., for x<sup>2</sup> = 49), taking square roots, completing the square, the quadratic formula and factoring, as appropriate to the initial form of the equation. Recognize when the quadratic formula gives complex solutions and write them as a ± bi for real numbers a and b. (Grades 9 - 12)  ...show
- International Technology and Engineering Educators Association: Technology
- Next Generation Science Standards: Science
- Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy. (Grades 9 - 12)  ...show
- Design, build, and test a model wind turbine.
- Describe how water turbines transfer the energy of water into electricity.
- List several advantages and disadvantages for using hydroelectric power.
- A cylindrical block of wood, at least 1 inch (2.54 cm) in diameter and about 8 inches (20 cm) long
- Water Turbine Worksheet
- 1 or 2 multimeters or voltmeters
- 2 double-ended alligator clip wire test leads
- 1-2 DC hobby motors (available at RadioShack [suggested part numbers: 273-223, 273-047 or 273-106] or hobby stores; make sure the shaft does not have a gear on it)
- drill bit with a size equal to the diameter shaft of the hobby motor'
- two blocks of 2 x 4 wood, each about 5 inches (12.7 cm) long
- two 2.5-inch (6.35 cm) nails or screws
- hammer or screwdriver
- one 3-5-inch (7.6-12.7 cm) piece of PVC pipe with an interior diameter that is slightly larger than the diameter of the blocks of cylindrical wood used for turbine construction
- various materials from which turbine blades can be constructed, such as index cards, plastic bottles, paper or plastic cups, cardboard, particle board, thick poster board, foam board, thin dowel rods, bamboo skewers, etc.
- strong tape, such as duct tape or packing tape
- pitcher, plastic bottles or cups to hold and pour water (the more the better)
|conservation of energy:||A physical law stating that the energy of a system must stay constant and that energy cannot be created.|
|conservation of mass:||A physical law stating that mass can neither be created nor destroyed.|
|energy:||The ability of an object to do work.|
|energy transfer:||The process through which energy is converted from one form to another.|
|generator:||A device that converts mechanical energy into electrical energy.|
|head:||Elevation difference of water between two locations.|
|hydro energy:||Energy generated from the movement or falling of water.|
|kinetic energy:||An object's energy due to its motion.|
|non-renewable energy source:||An energy source that is not replenished in a short period of time.|
|potential energy:||The energy stored in an object based on its position.|
|renewable energy:||Energy derived from a renewable source.|
|renewable energy source:||An energy source that is replenished naturally in a short period of time.|
|voltmeter:||An instrument that measures voltage.|
|water turbine:||A mechanical device that generates electricity from moving water.|
|work:||The mechanical transfer of energy from one object to another.|
Before the Activity
- A few days before the activity, have students gather and bring from home a variety of plastic bottles, cardboard and other materials from which turbine blades can be made.
- Gather materials and make copies of the Water Turbine Worksheet, one per group.
- Drill a hole on one end of each cylindrical block of wood equal in diameter to the diameter of the shaft of the hobby motor. Place the hole as close to the exact center of the wood as possible.
- Assemble the turbine testing device(s) using the wooden blocks, nails or screws, PVC pipe, DC motor, duct tape and alligator clip wires, as shown below.
- In this activity, each group creates a turbine on their own cylindrical block of wood and then takes turns placing their turbines on the class turbine testing device(s) to measure voltage.
With the Students
- Divide the class into groups of three students each.
- Distribute the worksheets and blocks of wood.
- In a class discussion, generate the problem that the students are trying to solve by designing water turbines; this should include how to generate electricity for a house using a renewable energy source.
- In groups, have students brainstorm how they might design their water turbines. Possible questions to address: How many blades? How to space them? From what material should we make the blades? What shape for the blades? Have students record all their brainstorm ideas on their worksheets.
- From a review of their brainstorming exercise results, have each group agree upon one design to build for their turbine model. Direct them to draw their designs on their worksheets and explain why they chose that design.
- Next, have each group use the available materials to build a prototype of their turbine based on the design. Note: Since the motor will be placed directly into the cylindrical block of wood, make sure students attach their turbine blades to the end opposite of the hole drilled into the wood block; this prevents the motor from falling directly in the path of water during testing.
- Once a group has finished building its turbine, have them go outside or over a large sink to test how well they work.
- For testing, have a group put the end of the model turbine through the PVC pipe on the testing device and onto the shaft of the motor. You may want to tape the front end of the testing device to the surface it is sitting on in order to prevent movement during testing. Once the turbine is connected, have one student pour water onto the turbine. Have the teacher or another student measure and record the length of time the water hits the blades.
- Have each group take turns pouring water over the blades of their turbine from three different heights, recording the data on the worksheet.
- Have students complete the calculations and analysis on their worksheets.
- Conclude with a class discussion to review and compare the groups' findings. What improvements would they make? Where would they locate turbines near their energy efficient houses? See additional post-activity discussion questions in the Assessment section.
- Have student teams present their designs to the rest of the class, as described in the Assessment section.
- Take care not to perform the turbine testing at a location where the floor will become slippery when wet.
- Keep water from falling directly onto the motor. A little splashing is okay, but since some electrical connections are involved, a lot of water could potentially damage the motor or harm a student.
- How can water be used to generate energy and electricity?
- What are some advantages in creating and using hydroelectric power?
- What are some disadvantages?
Activity Embedded Assessment
- What parts of your designs seemed to produce greater efficiencies in the turbines' abilities to convert water's energy into electricity?
- What parts of your designs seemed to produce lower efficiencies?
- How could we combine different design ideas from all the groups into one turbine that might have a greater efficiency than the individual turbines?
- A kilowatt hour (kWh) is often used when discussing electrical energy usage. Show that the units of a kWh are equivalent to the unit of energy, the joule. (Hint: Watt = J / s)
- The power associated with an elevation difference of a flowing fluid is given above to be: P = (mass flow rate)gh. Show that the units of this equation are equivalent to the SI units of power, watts.
- For younger students, eliminate the mathematical analysis from the worksheet.
Additional Multimedia Support
Bonsor, Kevin. How Hydropower Plants Work. September 6, 2001. HowStuffWorks.com. Accessed March 31, 2009. http://people.howstuffworks.com/hydropower-plant1.htm
Hoover Dam, Visiting Hoover Dam. Last reviewed March 2009. Lower Colorado Region, Bureau of Reclamation, US Department of the Interior. Accessed March 31, 2009. http://www.usbr.gov/lc/hooverdam/
Hydropower Basics. Last updated January 8. 2008. Wind and Hydropower Technologies Program, Energy Efficiency and Renewable Energy, US Department of Energy. (how hydropower works, types of hydropower plants, types of hydropower turbines, glossary of terms) Accessed March 31, 2009. http://www.eere.energy.gov/basics/renewable_energy/hydropower.html
Tyler Maline, Lauren Cooper, Malinda Schaefer Zarske, Denise W. Carlson
© 2007 by Regents of the University of Colorado.
Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Last modified: March 4, 2015