Lesson Write-Up For Spring Quarter 2013
Your name: Meg Babakhanian and Abigail Curtis
Title of Lesson: An Electrifying Challenge!
Grade Level: 9-12
Subject(s): Physics
Summary:
Student scientists must use their critical thinking skills and knowledge of electricity and
magnetism to try to win a challenge. Students will construct and modify the performance
of hand-crank generators to try to win a challenge. This lab demonstrates that electricity
results from a transfer of energy and to demonstrate the relationship between electric
and magnetic phenomena. This lab will allow students to physically feel this transfer of
energy and appreciate that electricity can be generated using simple and common
items.
Time Required: 2, 50 minute class period
Group Size: 7 groups of 4-6 students
Cost to implement:
<$10 per group
$20 per 10 groups: 300ft per group: 30-gauge enameled copper magnet wire (see the
following site for good places to order materials at reasonable prices:
http://amasci.com/amateur/coilgen.html) some places sell a >3,000ft spool for
under $20, which would cover 10 lab groups per lab period. We had students
reuse the same wire each period, which also saved on supply costs.
$2.50 per group: 2 ceramic magnets (1x2x5cm) per group
$15 covers entire class: 1 3.5” nail per group
$5 covers entire class: 10 pack of Electrical tape
$2 per group: one, 1.5 volt LED light bulb per group
Enough cardboard to make one generator frame per group using the dimensions below:
8cm
8cm
3.5cm
8cm
3.2cm
7.7cm
Learning Goals:
After this lessons students should be able to:
1. Understand that electricity and magnetism are related.
2. Identify the various parts of an electromagnetic generator and how it generates
electricity.
3. Understand that the basic design of the generator that they constructed is found
in all electromagnetic generators (e.g. wind turbines, car alternators).
4. Apply their knowledge of series and parallel circuits to generate enough
electricity to light two LED lights.
Level of Inquiry:
Students were engaged in guided inquiry through this lesson. They must use their
knowledge of how circuits work in order to organize their generators and light bulbs so
that both light up.
Introduction / Motivation:
Electricity is something that many people do not think much about until it goes out. We
depend on electricity for light when it is dark, to cook food, warm/cool our homes,
entertain ourselves, etc. Much of our electricity comes from electromagnetic generators
that are composed of a coil and a magnet that moves relative to the coil and causes a
change in magnetic flux, which results in electricity. From giant wind turbines to car
alternators, the basic design of electromagnetic generators is the same, and it is
possible to build one using simple materials. Through this activity, students will learn the
basic components of an electromagnetic generator, construct their own generators
capable of lighting a 1-volt LED light bulb, and develop a way to get their generators to
light 2 LED bulbs using what they have learned about circuits and generators.
Lesson Background Concepts for Teachers:
Magnetic flux is the amount of a magnetic field that passes through a surface (such as a
coil). When the flux changes (by moving the coil relative to the magnet, or vice versa),
voltage is generated. This is how electrical generators, such as those found in wind
turbines, car alternators work. In a wind turbine, the wind moves the turbine (mechanical
energy), which turns a magnet inside a coil and generates electrical energy.
Procedure: See detailed illustrated procedure in attached pdf.
Day 1: Students are given a lesson on electromagnetism that covers how current and
voltage are generated by changing magnetic flux through a coil.
Day 2: Laboratory Challenge:
1. Students are shown a homemade hand-crank generator light up a light bulb and
asked to figure out how the light bulb was lit using their knowledge of how
electricity is generated in a “Think, Pair, Share” discussion.
2. Students will then receive instructions on how to build their own generators with
their lab groups. Their generator should be capable of producing a voltage of 1V
– 1.5V to light the bulb, which they must measure using the voltage meter.
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3. The students must now modify their generators to light two light bulbs.
4. Students will then showcase how they tried to modify their generators and their
reasoning behind their modifications. Students will discuss which were the best
way(s) to build a more powerful generator.
Materials List
Each group of students will need:
 300ft (must be continuous) of 30-gauge electromagnetic wire
 Cardboard generator frame
 2 strong magnets
 electrical tape
 1 iron nail that is long enough to fit all the way through the cardboard base
 Voltmeter to measure voltage and current
 Alligator clips
 1, 1.5volt LED bulb
Safety Issues:
 The wire is very fine and hard to see, so students should mind where they
unwind the wire so that nobody is tripped.
 The voltage generated by these generators is extremely low, so there should be
no danger of electric shock.
Lesson Closure:
We will show the class examples generators similar to those that they constructed that
power their everyday lives, focusing on renewable sources like wind, tidal, etc. There
are also a number of gyms where the exercise machines have generators that give
power back to the grid and even power videogames on the machines.
Assessment:
Students will take data during the lab and answer related questions at the end. Students
will also discuss their findings in class and will try to determine which was the best way
to modify a generator to produce enough voltage to light the two light bulbs.
References:
Building a hand-crank generator: http://amasci.com/amateur/coilgen.html
Attachments:
Lab Procedure: Generator_Lab.doc
List CA Science Standards addressed:
5. Electric and magnetic phenomena are related and have many practical applications.
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