A Hydroelectric Dam Engineering Teaching Kit

Don’t Leave it to Beaver

A Hydroelectric Dam Engineering Teaching Kit

The University of Virginia

School of Engineering and Applied Sciences

Michael Underhill

Michael San Antonio

Colin O’Brien

Jason Kaplan

Point of Contact: Michael San Antonio

Concepts:

Hydrostatic Pressure, Potential and Kinetic Energy,

Simple Machines, Electricity
TABLE OF CONTENTS

Executive Summary______2

Applicable SOL’s______3

Materials Needed______4

Unit Overview______5

Unit Preparation______7

Day 1: Intro to Hydroelectric Dams and Energy______8

Lesson Plan ______8

Worksheet: Hydrostatic Pressure & Water Flow______12

Worksheet: Energy ______13

Day 2: Turbines and Mechanical Energy______14

Lesson Plan ______14

Worksheet: Torque______16

Day 3: Electricity and Magnetism______17

Lesson Plan ______17

Worksheet: Electricity and Magnetism Exercise______20

Worksheet: Motors and Generators______21

Day 4: Integration and Testing______22

Lesson Plan ______22

Worksheet: Initial Hydroelectric System Design______24

Worksheet: Expectations______25

Day 5: Competition ______26

Lesson Plan ______26

Worksheet: Lessons Learned______28

Citations ______29

Executive Summary

The mission of the Don’t Leave it to Beaver Engineering Teaching Kit is to educate middle school students on some major concepts in engineering and sciencein the inner workings of hydroelectric dams. While we are primarily concerned with the technical and engineering aspects of these systems, the broader context of “clean” energy is also anideathat this teaching kit drives home. Some of themain concepts included in this kit are potential, kinetic, and electrical energy and the relationships between them. Torque, motors/generators, and water flow are also key components of our lesson plan.

Considering the present energy crisis and issues of global warming facing the world, renewable and clean energy is an extremely importanttopic. Hydroelectric power is just one of a number of renewable solutions which include solar, wind, and geothermal power as well.

Throughout our process, students will see many demos, build various parts of the hydroelectric system, and make crucial decisions for their final product. They will learn to work as a team and fully experience the engineering design process. This process includes: problem identification, brainstorming, design, construction, testing, and improvement. Studies have shown that hands-on learning is extremely effective for engineering education. Younger students are more impressionable and develop constructs that will affect how they will learn in the future. Therefore, it is crucial to instill an early interest in engineering through fun and interactive activities. Our goal is to form the fundamental building blocks they need to solve critical problems of the future.

The entire lesson plan is centered around the competition on the fifth day. The concepts taught on the first few days are integrated into their final design. The students will select a generator, build a turbine and shaft structure, and route water [CJO1]incorporating those elements into a pre-built structure to create a complete hydroelectric dam within a tank. The teams will compete to produce the most electrical power. While the final results are important, we want the students to be able to explain their decision process and walk away from this experience with a greater interest in engineering.

Applicable SOL’s

PS.1 The student will plan and conduct investigations in which

a) chemicals and equipment are used safely

b) length, mass, volume, density, temperature, weight, and force are accurately measured and reported using metric units (SI)

c) conversions are made among metric units, applying appropriate prefixes

e) numbers are expressed in scientific notation where appropriate

g) independent and dependent variables, constants, controls, and repeated trials are identified

k) valid conclusions are made after analyzing data

i) research methods are used to investigate practical problems and questions

n) an understanding of the nature of science is developed and reinforced

PS.6 The student will investigate and understand states and forms of energy and how energy is transferred and transformed. Key concepts include

a) potential and kinetic energy

b) mechanical, chemical, and electrical energy

PS.10 The student will investigate and understand scientific principles and technological applications of work, force, and motion. Key concepts include

a) speed, velocity, and acceleration

b) Newton’s laws of motion

c) work, force, mechanical advantage, efficiency, and power

d) applications (simple machines, compound machines, powered vehicles, rockets, and restraining devices).

PS.11 The student will investigate and understand basic principles of electricity and magnetism. Key concepts include:

a) static electricity, current electricity, and circuits

b) magnetic fields and electromagnets

c) motors and generators

Materials Needed

Material / Quantity / Location / Price/qty / Manufacturer / Part #
2 liter soda bottle (2) / 2 / Common
Pitcher for pouring water / 1 / Common
Tank / 1 / Whatever is available
Ball / 1 / Common
String / 1 / Common
Corks / 2 types/group
Plastic Spoon heads (various sizes) / 1 set/group
Plastic Knives (various sizes) / 1 set/group
Popsicle sticks / 1 box
Balsa Wood
Glue (waterproof) / 1/group / Common
Scissors / 1/group
Permanent bar magnets / 1 Set of 12 / / $7.80
Coiled wire / 5 coils / Allied Electronics Website / $30.88/100 ft / Alpha Wire / 3051-BK005
Multi-Meter Test Leads / 2 / Allied Electronics Website / $4.56/cable / Mueller / Top of Form
BU-1031-A-24-2
Bottom of Form
Multi-meters / 1/group / Allied Electronics Website / $29.24 each / Amprobe / Top of Form
DM7C
Bottom of Form
DC Brush motors (3 different choices) / 3 per team / Allied Electronics Website / $16.77/motor / Parvalux Motors / 52310
Batteries (various types)
Wood (2x4, for dam support structure)
Garden hose (or other access to water)
Plywood (Dam Construction) / 1 sheet / Available at hardware stores / $20
Rubber Stoppers (3 different sizes) / 3 of each size / Available at hardware stores / $1.00
Legos (shafts)
Exacto Knives / 1 set of 13 / Available on amazon.com / $6
Wood Glue
Hot Melt Glue
Hose of various sizes
Duct Tape

<Pictures of the non-common items will be added in the future>.

Unit Overview

The first three days of this lesson plan are devoted to teaching a number of valuable concepts related to hydroelectric power generation. Activities and demos are used throughout these days to further enhance the ideas and allow students to learn more effectively. The fourth day is primarily a construction and integration class where students will have the opportunity to apply their new knowledge and work together in a team environment. The fifth and final day is reserved for the team competition of their hydroelectric systems and a general wrap up of the major ideas and lessons learned.

Day 1: Introduction to Hydroelectric Dams and Energy

Preliminary Lesson Summary:

Students will be introducedto hydroelectric dams by showing them some famous dams and explaining why they are important. Next, hydrostatic pressure and the various forms of energy will be discussed usingdemos and worksheets. The day will conclude with a demoof the example dam anda quick discussion of safety.

Objectives:

Introduce students to hydroelectric dams and why they are important
Educate students on the principle of hydrostatic pressure and how it relates to dam structures, geometries, and power generation
Educate students on threemajor forms of energy: potential, kinetic, electrical
Address safety issues, especially with regards to water and electricity

Day 2: Turbines and Mechanical Energy

Preliminary Lesson Summary:

Teams will be introduced to general examples of turbines and their basic principles will be covered. Demonstrations will be used to explain the concept of torque and the methods to maximize it. As students gain an understanding of mechanical energy in turbines they will be introduced to their given materials and individually draw up possible designs for a turbine, giving them a chance to apply these principles. After some discussion team members will compare designs and then collaborate to build one turbine for their team, which will later be used during their final competition.

Objectives:

Introduce students to turbines and how they are used in hydroelectric power generation
Describe principles of torque and maximization
Encourage planning, design, and problem solving in the building process
Student teams build their turbines for use in their hydroelectric systems

Day 3: Electricity and Magnetism

Preliminary Lesson Summary:

Teams will be introduced to the concepts of electricity and magnetism and how they are used to produce power. Teams will learn how to perform some basic measurements on a vital electronic instrument called a multi-meter. They will then use the multi-meter to explore the functions of generators and motors and how they are different. They will conclude the lesson by analyzing a set of generators and will choose the best one to incorporate into their turbine design from Day 2.

Objectives:

Explore fundamental concepts of electricity and magnetism
Understand how motors and generators work and know how they are different.
Understand basic circuit concepts
Learn the basics of how to produce electrical power from mechanical work

Day 4: Integration and Testing

Preliminary Lesson Summary:

Today consists mostly of allowing the students to work together freely in their teams to complete their hydroelectric systems. Teams must integrate their parts made/selected from the first three days of this project and determine how best to direct the flow of water to their turbine. Additionally, as teams are ready, they may test their systems within the tank using water and make adjustments as necessary.

Objectives:

Students integrate turbines and generators from days 2-3
Groups determine how best to funnel the water from the dam
Teams complete their hydroelectric systems
Students test systems and make adjustments as necessary

Day 5: Competition

Preliminary Lesson Summary:

Today is the day of the grand competition where students’ hopes and dreams will be either fulfilled or crushed in a climax of excitement, but either way they will be learning! Each of the teams will have an opportunity to test their systems and attempt to generate the most power. Afterwards, the lessons learned will be summarized and stressed for better retention.

Objectives:

Every team has the opportunity to test their hydroelectric system
Students learn the concepts covered in days 1-4 by seeing them in action
All major concepts are reviewed afterwards
Students provide feedback on their team, the competition, and lessons learned

Unit Preparation

<We will contain construction pictures within our explanations.>
Day 1: Intro to Hydroelectric Dams and Energy

Extended Lesson Summary:

Students will be introduced to the basics of hydroelectric dams, how they derive their energy, and why they are shaped the way they are. Theadvantages and drawbacks of hydroelectric dams will be discussed to give students an idea of the bigger picture of power generation. A few famous dams will be displayed and discussed to stimulate interest and further emphasize the importance of hydroelectric power. Hydrostatic pressure is a major concept that will assist in describing the structure and design of dams and this concept will be explored in the lesson plan. Next, the various forms of energy (potential, kinetic, electrical) will be discussed while usingworksheets and demos to increase the understanding of these important physical properties. Students will be introduced to their competitionwhile seeing a completed hydroelectric dam in action. Finally, they will be broken up into teams. It is vital to discuss a few safety precautions on this day as well, notably the safety issue of working with water and electricity in close proximity.

Objectives:

Introduce students to hydroelectric dams and why they are important
Educate students on the principle of hydrostatic pressure and how it relates to dam structures, geometries, and power generation
Educate students on threemajor forms of energy: PE, KE, EE
Get students excited about the rest of the week and the design competition
Address safety issues, especially with regards to water and electricity

Virginia SOL’s:

PS. 1a
PS. 6a, PS. 6b

Materials:

2 liter soda bottle (2)

Scissors or Knife

Pitcher for pouring water

Tank (to catch the water)

Ball

String

Worksheets: Hydrostatic Pressure & Water Flow, Energy

Teacher Prep (20 min):

Make photocopies of two worksheets (One copy per student)

Prepare PowerPoint or overhead slides

Cut holes in soda bottles – three different heights in one, three different sizes in the other

Attach ball to string securely

Secure other end of string to fixed object

Detailed In Class Lesson Plan:

Introduction to Hydroelectric Dams (10 min):

Students will be presented a short power point (overhead transparencies if necessary) of some famous dams. A few very basic images will be shown to students to help reveal the major elements and operations of a hydroelectric dam. Finally discussion of the advantages and drawbacks of hydroelectric dams will give students a clear understanding of the broad issues faced in power generation.

General Concepts for Students

Water has energy from the air above pushing down on it

Water gets pushed into the tunnel where it gains speed

Water falls onto turbine causing it to spin

Spinning turbine producers power in the generator

Generator converts spinning energy into electricity

[mdu2]

Discussion of Hydrostatic Pressure and Water Flow(15 min):[mdu3]

Teacher will break down the word

Hydro – having to do with water

Static – staying still

Hydrostatic – still water

Demo: Teacher will then demonstrate hydrostatic pressure with a 2 liter soda bottle and three holes at various heights. The water at the bottom hole shoots out fasterthan fromthe holes above it. In order to illustrate water flow principles,another bottle should have three holes of different sizes all at the same height. Now,the water from the smallest hole shoots out faster than from the other holes. Students will try to figure out why and fill out the Hydrostatic Pressure & Water Flow worksheet. Teacher will aid students with this worksheet.

Finally, the teacher will show them the hydrostatic pressure and mass flow equations.

pressure = density*gravity*height

mass flow = area*density*velocity

[mdu4]Teacher explains how the phenomena affect the structure and design of a dam.

Discussion of Energy (15 min):

Teacher will explain how both Potential and Kinetic energy are associated with hydroelectric power and touch upon electrical energy (to be taught in great detail on day 3).

Potential Energy – exists when there isa force that tends to pull an object back to its original position, after it was displaced[JDB5][mdu6]

Examples: Gravity pulls object to the ground, and Springs pull themselves together

Gravitational potential energy is important in hydroelectric dam

PE = mass*gravity*height

Kinetic Energy – exists when there is an object in motion that contains mass.

Examples: cars, baseball, (students give some examples)

Water moving through tunnel is the kinetic energy in a hydroelectric dam

KE = ½ *mass*velocity2

Pendulum Demo:Teacher holds up a ball on a string and lets it go to see it swing back and forth. Potential energy is greatest at its peak and kinetic energy is greatest at its lowest point.

Electrical Energy – exists when there is a flow of electrons through a load.

Electrical energy is the output of a hydroelectric dam and is the energy that powers the TVs and light bulbs in one’s home.

Here are some links to further information on these concepts if you need a refresher:

Forms of Energy:

Pendulum Demo:

Hydrostatic Pressure:

Demonstration of Instructor’s Dam (5 min):

The teacher will show students their version of a hydroelectric dam in order to prove to the students that moving water really can produce electricity. Avoid showing students the inner workings of the dam by covering the major components to promote innovative ideas for theircompetition. The design competition is introduced at this point in the lesson and the class will break up into teams.

Wrap Up (5 min):

Students will be informed of safety measures when dealing with water and electricity. Also safety in using the tools such as knives or rough sandpaper shall be addressed. Teacher will first ask class what they learned during this lesson. Then the teacher will inform students of up coming lesson plans and concepts.

[mdu7]
Name ______Date ______Class ______

Hydrostatic Pressure & Water Flow

Definitions:

Hydro - having to do with water

Static - Something that is not in motion

Hydrostatic - water at rest

Questions:

Hydrostatic Pressure Demo

For bottle number 1, out of which hole do you think the water will shoot the fastest? (Circle One)

BottomMiddleTopAll the same

Explain why some of the holes made the water shoot faster than others?

For bottle number 2, out of which hole do you think the water will shoot the fastest? (Circle One)

SmallMediumLargeAll the same

Explain why some of the holes made the water shoot faster than others?

Name ______Date ______Class ______

Energy

Brainstorm: Name all of the forms of energy that you can think of:[JDB8]

Questions:

Pendulum Demo

1) What or who gave the ball its initial energy?

2) How fast is the ball traveling when it reaches the top of its cycle?

3) At what point is the ball traveling the fastest?

4) At what point in the path of the ball is the potential energy the greatest?

5) At what point is the kinetic energy the greatest?