TeachEngineering Digital Library: teachengineering.org
http://commons.wikimedia.org/wiki/File:Waterwheel.jpg

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
http://www.teachengineering.org
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SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
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http://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/c ub_energy2/cub_energy2_lesson08_activity2.xml

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
Full Activity on TeachEngineering
• Students construct a waterwheel using two-liter bottles, dowel rods and index cards, and calculate the power created and work done by them.
• Engineering focus: o Engineering Design Process
• Students brainstorm, design, test, collect data, and analyze results for waterwheel blades for the purpose of creating the most efficient waterwheel
• Learning objectives: o Make a connection between the concepts of power and work and engineering design.
o Work in a design group.
o Explore nonlinear functions (ex. power is inversely proportional to time).
o Collect data to solve equations and form conclusions.

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
• Suggested time: 45 minutes
• Suggested group size: 4 students/group
• Materials o Each group needs:
• 2-liter bottle with caps (drill 3/8-inch holes into the end of the two-liter bottle and the cap.) *
• ¼ -inch dowel rod (must be longer than the 2-liter bottle)
• 15 index cards
• 1.2 meters of string
• scissors
• tape
• a 100-200 gram weight (about 1/3 pound)
• stopwatch
• kilogram or gram scale
• pitcher or water jug
• funnel
• H
2
0 Solutions Worksheet , one per person )
*Prepare plastic bottle and bottle cap prior to activity http://www.teachengineering.org/view_activity.php?url=collection/c ub_/activities/cub_mechanics/cub_mechanics_lesson05_activity1.xml

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
• Throughout human history, waterwheels performed many types of mechanical work : saw timber, drive pumps, run farm equipment, trip hammers, grind grains into flour, make iron products and power textile mills. http://itd.idaho.gov/transporter/2011/101411_Trans/10141
1_StuddedTires.html
https://www.cpsc.gov/en/Recalls/2014/Rollerblade-
USA-Recalls-Tempest-Inline-Skates/ http://gallery.usgs.gov/tags/mine

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
• Today, the modern equivalents of waterwheels are the huge turbines of hydroelectric power plants , which generate electricity that we use everyday to perform all types of work: heating, cooling, refrigeration, and the powering of appliances, televisions and entertainment.
• Hydropower is a way to produce electricity using a renewable energy source that does not use fossil fuels, pollute or produce greenhouse gases. Such big projects require engineers to consider all the implications of their impact on the surrounding environment.
http://commons.wikimedia.org/wiki/File:Kurpsai_Hydroe lectric_Station.jpg
http://www.nypa.gov/facilities/niagara.htm
http://commons.wikimedia.org/wiki/File:POWERHOUSE,_PELTON-
FRANCIS_TURBINE_(GENERATOR)_-

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
Vocabulary Terms energy hydroelectric power
(hydropower) kinetic energy potential energy power water turbine waterwheel work
The capacity to do work.
Definitions
The production of electrical power through the use of the gravitational force of falling or flowing water.
Energy of motion.
Stored energy due to position or configuration (example: gravitational potential energy).
The rate of doing work; the amount of energy consumed per unit of time.
A rotary engine that transforms the mechanical energy of moving water to electrical energy. A water turbine generates electric power from water’s kinetic energy.
A machine for converting the kinetic energy of flowing or falling water into useful forms of power
An activity involving a force and movement in the direction of the force.

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o Power and work are important concepts that impact the engineering design of items ranging from racecar engines to elevators to power plants.
• High-power cars (high-horsepower) are able to accelerate very quickly and go very fast.
• Elevators in skyscrapers require enough power to lift many people quickly, to avoid long elevator waiting lines.
• Power plays an integral role in the production of hydroelectricity.
o Work is measured in Joules (J) and is defined as a force acting over a distance or:
Work = force x distance http://dnr.louisiana.gov/assets/TAD/education/ECEP/diesel/f/f.htm

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o In our activity today, work will be done lifting a weight. o The force term equals the weight and the distance term equals the height lifted. o Power is measured in Watts (W) and is defined by how fast work is done or:
Power = Work ÷ time

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o In this activity, you are working for H waterwheels and water energy!
2
O Solutions, an engineering design firm that works mostly with o Your city wants to use hydropower instead of coal to make energy because they are worried about air pollution. The city has hired you to design an efficient watermill. o The firm (our class) has been split into several engineering teams (student groups). Each engineering team will design and test a slightly different design so that the firm can present the most efficient design to the city. o You will calculate power and work by measuring force, distance and time for your team-built waterwheel.

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
1. Gather supplies: Gather materials and make copies of the H
Solutions Worksheet , one per student.
2
0
2. Prepare materials: Prior to the activity, drill 3/8-inch holes into the end of the two-liter bottle and the cap. This allows the bottles to spin symmetrically and freely about the dowel rod. (If you don't have the hole in the cap, the dowel rod will not spin symmetrically.).
http://www.teachengineering.org/view_activi ty.php?url=collection/cub_/activities/cub_ener gy2/cub_energy2_lesson08_activity2.xml

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
1. Divide the class into groups of four and pass out the materials.
2. Remind students of the context of the design challenge (they are engineers working for a firm hired to design an efficient water wheel). They should keep track of their design process using the worksheet.
3. Instruct students to attach the index cards to the sides of the two-liter bottle to create a waterwheel (open-ended).
• Encourage students to brainstorm different ideas of where to place the index cards.
• Explain that the water will be supplied from a pitcher through a funnel and the bottle will spin on the dowel rod.
http://www.teachengineering.org/view_activi ty.php?url=collection/cub_/activities/cub_ener gy2/cub_energy2_lesson08_activity2.xml
http://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/c ub_housing/cub_housing_lesson04_activity1.xml

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
4. When the students are finished with their design, have them tie the string to the cap end of the bottle so that when the bottle rotates, the string wraps around the bottle neck, pulling up the string.
5. Measure and tie a weight to the other end of the string.
• Make sure to record the mass of the object in kilograms (kg). (For example, 100 grams is 0.1 kg.) Multiply the mass by gravity (~10 m/s 2 ) to calculate your force in
Newtons (N).
• Have everyone use about the same amount of weight.
• Make sure the weights are not too heavy to lift. (For example, 100-200 gram weights work well)

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
6. Test the waterwheels by pouring water through a funnel to achieve an even flow, and timing how long it takes to lift the weight 1 meter (This is your distance).
• Perform this test outside or over a sink.
• Have two students hold the ends of the dowel rod, one student pour the water and one student time how long it takes and write it down.
• Make sure the funnel is only a couple of inches above the waterwheel each time.
7. Have students calculate the work and power of their waterwheel.
Work = force x distance
Power = Work ÷ time
8. Which team had the most power? (Answer: They will all do the same amount of work, but faster wheels will have more power!)

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o Pre-Activity Assessment o Brainstorming: In small groups, have students engage in open discussion. Remind students that no idea or suggestion is "silly." All ideas should be respectfully heard.
Write down all the groups' ideas on the board to share with the class.
"What features make a good waterwheel?"
(Possible answers: a lot of fins/index cards to turn the wheel/bottle, each fin/index card holds a large amount of water, symmetry, etc.) o Activity Embedded Assessment o Prediction: Have each student group predict how their waterwheel is going to do and why. Based on their prediction, ask each group if their wheel will do more work or have more power than the other groups.
(Answer: They will all do the same amount of work, but faster wheels will have more power.)

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o Post-Activity Assessment: Question/Answer
Have students answer the following question in a short paragraph: o Explain the difference between work and power in your own words. (Answer: Work is a force acting over a distance and is measured in Joules and not dependent on time. Power is work divided by time and is measured in Watts.)
Put the following problems on the board (or overhead project) and have students solve them: o Mr. Muscles loads up a bar with 910 Newtons (≈205 lbs) of weight and pushes the bar up over his head 8 times.
Each time he lifts the weight .5 meters. How much work did he do? If he does the whole thing in 15 seconds, how much power did it take?
(Answer: Work = 3640 Joules. Power = 242.7 Watts. See work, below.)
Work = Force x Distance
Force = 910 Newtons
Distance = .5 meters x 8 = 4 meters
Work = 910 Newtons x 4 meters = 3640 Newton•meters = 3640 Joules
Power = Work ÷ time = 3640 Joules ÷ 15 sec = 242.7 Joules/sec = 242.7 Watts o How long does it takes a swimmer with a power output of 275 Watts to accomplish 3600 J of work?. If she applied a 650 N force during that time with the same power output, how far did she swim?
(Answers: Power = Work / time --> time = Work / Power = 3600 J / 275 Watts = 13.1 seconds.
Power = (Force * Distance) / time --> Distance = (Power * time) / Force = (275 Watts * 13.1 seconds) / 650 N
= 5.54 meters))

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
Power, Work and the Waterwheel
o Emphasize the science concepts, vocabulary, and engineering connection; reinforce these throughout the activity.
o If the weight is too heavy, the waterwheel may not work. If the weight is too light, you won't get an accurate measurement of the waterwheel's power.
o Make sure students do not use the dowel rods inappropriately.
If testing inside and on tile, the floor may be slippery when wet.

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
• Teambuilding skills o Working together on designing, building and testing waterwheel blades
• Engineering skills o Engineering Design Process: Students design blades for their water wheel, test and collect data, perform calculations and analyze results.
• Encouragement through hands-on learning o Students learn about engineering design, concepts of work and power, and about the use of waterwheels/water turbines.
• Motivation through having fun o Introduce the activity as a fun learning experience!
http://www.buckeyeaz.gov/index.aspx?nid=163

SHPE Foundation
SHPE Jr. Chapter Curriculum
Hands-On Activity Training
• TeachEngineering: http://www.teachengineering.org/ o over 1,300 standards-based engineering lessons and activities
• Carleigh Samson, TeachEngineering Editor o carleigh.samson@colorado.edu
o 303.492.6950
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