Objective
Build a motion-powered electrical generator and experiment to see if there is a relationship between the number of
magnets used and the number of LEDs the generator can power.
Shaking Up Some Energy
Kit Contents
QTY ITEM DESCRIPTION
1
30 AWG magnet wire, ¼ pound spool containing 825 feet of wire
6
12 x 3 mm neodymium magnets
10
Red LED lights
1
1.9 x 1.3 inch solderless breadboard
2
Alligator clip leads
Introduction
You are probably familiar with magnets from your everyday life. Magnets come in all shapes and sizes (see Figure 1), but
all magnets have one thing in common—they are surrounded by an invisible magnetic field, which has a north pole and
a south pole. A magnetic field can push and pull on other magnets. Similar poles (north and north or south and south)
repel each other; opposite poles (north and south) attract each other.
You will also need from home:
- Safety glasses
- Cardstock, 8.5 x 11 inch sheet
- Corrugated cardboard, 3 x 6 inch
- Scissors
- Hobby knife or utility knife
- Ruler
- Pen or pencil
- Scotch tape
- Fine-grit sandpaper, 2 x 2 inch piece
- Craft glue
- Optional: power drill
Summary
Prerequisites
None
Safety
Neodymium magnets are very strong and can pinch your fingers when they come together.
You should keep them away from pets and small children because they can cause serious
harm if ingested. As with any magnet, you should keep them away from computers, cell
phones, and credit cards.
Frequently Asked
Questions
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Energy_p009.shtml#help
Abstract
Figure 1. (Left) A bar magnet with its north and south poles labeled with N and S, respectively. (Center) A "horseshoe"
magnet. The magnet's poles are attracting tiny iron filings. (Right) Two tiny cylindrical magnets next to a matchstick to
show their size. Each type of magnet is surrounded by an invisible magnetic field.
Did you know that there is actually a relationship between magnets and electricity? Electrical current flows through all of
the electronic devices you use every day, from table lamps and toasters to computers and cell phones. Electrical current
is carried by conductors—usually metal wires that allow electricity to flow easily. It turns out that when you move a
magnet near a conductor, the magnetic field causes (or induces) a current in the conductor. This is called magnetic
induction, and this principle is used in generators to generate electricity. Most generators involve coils of wire (Figure 2),
which let you fit a long length of wire into a tiny space. There are many different kinds of generators. Some are very
complicated and involve multiple coils and multiple magnets, while some are simple and have just one coil and one
magnet. Some are very large (like power plants that power entire cities), while some are very small, and can fit inside
portable radios or flashlights (Figure 2).
While you are probably quite familiar with battery-powered flashlights and watches, did you know there are motionpowered electronic devices—including some flashlights and watches—that can seemingly run forever without needing
new batteries? The secret involves using magnets that generate electricity when they move around near a metal wire. In
this science project, you will build your own simple motion-powered electrical generator that can power a series of tiny
lights.
Energy_p009_20140109.pdf
JAM-5220-KIT
http://www.physics4kids.com/files/elec_faraday.html (http://www.physics4kids.com/files/elec_faraday.html) .
For help creating graphs, try this website:
National Center for Education Statistics, (n.d.). Create a Graph. Retrieved June 2, 2009, from
http://nces.ed.gov/nceskids/createagraph/ (http://nces.ed.gov/nceskids/createagraph/)
Experimental Procedure
Safety Notes about Neodymium Magnets:
Figure 2. (Top) An illustration of a typical wire coil. Wrapping wire into a coil lets you fit a very long length of wire into a
small space. (Bottom) A picture of a flashlight with a wire coil and a magnet inside. Shaking the magnet through the coil
generates electricity.
In this electronics science project, you will build a simple generator with a single coil of wire and a magnet, kind of like the
flashlight shown above. To test your generator, you will use light-emitting diodes, or LEDs for short. LEDs are the tiny
lights you see in many electronic devices. Using more LEDs requires more electricity, so you will investigate whether
using more magnets (and thus increasing the strength of the magnetic field in your generator) allows you to light up more
LEDs.
Note: The flashlight in Figure 2 contains some additional circuitry that lets it store electricity for later use. The generator
you will build in this science project is very simple and does not store energy—the LEDs will only light up while you are
shaking it. If you want to build your own shake-to-charge flashlight, see the Make It Your Own (http://www.sciencebuddies.org/sciencefair-projects/project_ideas/Energy_p009.shtml#makeityourown)
Tab.
Terms and Concepts
Magnet
Magnetic field
Electrical current
Conductor
Magnetic induction
Generator
Light-emitting diode (LED)
Questions
What is magnetic induction? How can it be used to generate electricity?
Does stacking multiple magnets together make their magnetic field stronger?
Do you think a stronger magnetic field will generate more electricity (light up more LEDs)? Or does the strength of
the magnetic field not matter?
How can generators be used to power devices so they never need new batteries? Can you find examples of
products that advertise never needing batteries?
Handle magnets carefully. Neodymium magnets (used in this science project) are strongly attracted and snap
together quickly. Keep fingers and other body parts clear to avoid getting severely pinched.
Keep magnets away from electronics. The strong magnetic fields of neodymium magnets can erase magnetic
media like credit cards, magnetic I.D. cards, and video tapes. It can also damage electronics like TVs, VCRs,
computer monitors, and other CRT displays.
Keep magnets away from young children and pets. These small magnets pose a choking hazard and can
cause internal damage if swallowed.
Avoid use around people with pacemakers. The strong magnetic field of neodymium magnets can disrupt the
operation of pacemakers and similar medical devices. Never use neodymium magnets near persons with
these devices.
Use the magnets gently. Neodymium magnets are more brittle than other types of magnets and can crack or
chip. Do not try to machine (cut) them. To reduce the chance of chipping, avoid slamming them together. Eye
protection should be worn if you are snapping them together at high speeds, as small shards may be
launched at high speeds. Do not burn them; burning will create toxic fumes.
Be patient when separating the magnets. If you need to separate neodymium magnets, they can usually be
separated by hand, one at a time, by sliding the end magnet off the stack. If you cannot separate them this
way, try using the edge of a table or a countertop. Place the magnets on a tabletop with one of the magnets
hanging over the edge. Then, using your body weight, hold the stack of magnets on the table and push down
with the palm of your hand on the magnet hanging over the edge. With a little work and practice, you should
be able to slide the magnets apart. Just be careful that they do not snap back together, pinching you, once
you have separated them.
Wear eye protection. Neodymium magnets are brittle and may crack or shatter if they slam together, possibly
launching magnet fragments at high speeds.
Building Your Generator
1. First you will need to build the "coil form," the paper tube that you will use to wrap your wire coil. To start, you will
make a small tube that acts as a spacer between the magnet and the actual coil form to ensure the coil form is big
enough and the magnets do not get stuck.
a. Cut a piece of card stock that is roughly 7 centimeters (cm) x 15 cm, as shown in Figure 3.
b. Using all six magnets stacked together as a guide, roll the card stock tightly into a tube, as shown in Figure
3 (the resulting tube should be 7 cm long).
i. Important: Remember to follow all the safety rules listed above for neodymium magnets.
ii. If your magnets come with small, plastic spacers between them, carefully remove the spacers from
the stack before using the magnets as a guide to create the tube.
c. Use Scotch tape to secure the tube in place, as shown in Figure 3.
Bibliography
Andrew Rader Studios. (n.d.). Magnets. Physics4Kids. Retrieved September 25, 2013, from
http://www.physics4kids.com/files/elec_magnets.html (http://www.physics4kids.com/files/elec_magnets.html) .
Andrew Rader Studios. (n.d.). Current. Physics4Kids. Retrieved September 25, 2013, from
http://www.physics4kids.com/files/elec_current.html (http://www.physics4kids.com/files/elec_current.html) .
Andrew Rader Studios. (n.d.). Faraday's Law. Physics4Kids. Retrieved September 25, 2013, from
Energy_p009_20140109.pdf
JAM-5220-KIT
d.
e.
f.
g.
Use a hobby knife to cut out the smaller, inner circle. Be careful when using the knife.
Use the hobby knife or scissors to cut out the larger, outer circle.
Repeat steps 3.b.–3.e. for the other piece of cardboard.
Press both pieces of cardboard onto the ends of your coil form, placing them about 1.7 cm apart (just far
enough for the stack of all six magnets to fit in between them).
i. Note: If the cardboard pieces do not easily fit around the coil form, you can carefully use the knife to
make the inner circles slightly larger. You do not want to damage the coil form by forcing it in the
circle.
h. Use glue to secure both cardboard cutouts in place on the coil form. Wait for the glue to dry completely
before you continue to step 4.
Figure 3. Roll a 7 x 15 cm piece of card stock into a tube, using the magnets as a guide.
2. Use the tube you made in step 1 as a guide to make a second, larger tube. This is the tube you will actually use as
your coil form. The magnets will be able to easily slide back and forth in the larger tube without getting stuck.
a. Cut a second piece of card stock that is also 7 x 15 cm.
b. Using your first tube as a guide, roll the second piece of card stock into a tube, as shown in Figure 4.
c. Use tape to hold the tube in place, and remove the inner tube from the outer tube, as shown in Figure 4.
d. When you are done, you can set the smaller tube and stack of magnets aside.
Figure 5. Cut out cardboard circles and glue them onto your coil form (the larger card stock tube), as shown here. Note:
The bottom left image shows the stack of magnets so you know how far apart to space the cardboard pieces — the
magnets will not actually stay in this position.
Figure 4. Using the first tube as a guide, roll a second piece of card stock into a slightly larger tube.
3. Add cardboard circles to the sides of your coil form (the larger tube you just made) to act as guides for wrapping
wire around your coil form. All sub-steps are shown in Figure 5.
a. Cut two squares of cardboard, roughly 7 x 7 cm.
b. Use a pen or pencil to trace one of the circular ends of your coil form onto the middle of one piece of
cardboard.
c. Sketch a larger circle that reaches the edges of the cardboard square around the smaller circle (this circle
does not need to be exact).
Energy_p009_20140109.pdf
4. Wind wire around your coil form.
a. Unwrap about 60 cm of magnet wire from the spool it came in (do not cut the wire yet!).
b. Use tape to secure the wire to the inside of one of the pieces of cardboard, about 30 cm from the end of the
wire. This means you should have about 30 cm of wire dangling off of your coil form, as shown in Figure 6.
c. Carefully and tightly wrap the wire around the coil form, as shown in Figure 7, below. Count the number of
coil wraps you make as you go — you need to complete a total of approximately 1,500 coil wraps. Make
sure that the 30 cm segment of dangling wire stays free and does not get wrapped up in the coil; you will
need to access it later. Also, make sure that you always continue to wrap the wire in the same direction—do
not switch directions or your generator will not work.
i. Completing 1,500 coil wraps can take a while to do by hand, so be patient. Do your best to keep
track of the number of wraps, but you do not need to do exactly 1,500. It might help to put a tick mark
down for every 100th wrap on a piece of paper so you do not completely lose track of where you are.
ii. Tip: If you have a power drill available, you can use it to speed up the process (see the video below
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Figure 7 to find out how).
iii. Tip: To keep the dangling wire out of your way as you wind the coil form, you can push the dangling
wire into the coil form's inner tube.
d. When you have completed approximately 1,500 wraps of wire, leave about 30 cm of wire dangling off the
coil. Then use scissors to cut the other end of the wire. Use tape to secure the wire in place so it does not
unwind.
XDmvys)
Testing Your Generator
1. Set up your breadboard and LEDs.
a. You will use a solderless breadboard to easily connect multiple LEDs. The LEDs have metal wires sticking
out of them called leads (pronounced "leeds"). These leads can be easily inserted into and removed from
tiny holes on the breadboard.
b. Insert six LEDs into the breadboard in a staggered row, as shown in Figure 8. Important: LEDs have two
leads, one longer and one shorter. They represent the positive and negative sides of the LED, respectively.
In order for multiple LEDs to be connected in a row (also called in series), the negative lead of one LED
must be connected to the positive end of the next LED. Make sure that all of your longer (positive) LED
leads are positioned on the left, and all of your shorter (negative) LED leads are positioned on the right or
your experiment will not work properly.
i. It may help to think about the LEDs like a chain of people holding hands. If all the people are facing
the same direction, one person's right hand is holding the next person's left hand, and that person's
right hand is holding the next person's left hand, and so on.
c. See the Technical Note, below, for additional information about LEDs and breadboards (you do not need to
understand that information to complete this science project).
Figure 6. Tape the magnet wire to the inside of one of the cardboard pieces so that there is about 30 cm of wire
dangling off of your coil form.
Figure 7. Carefully and tightly wrap the wire around the coil form for a total of approximately 1,500 wraps. This figure
shows (top left) zero wraps, (top right) 500 wraps, (bottom left) 1,000 wraps, (bottom right) 1,500 wraps.
Watch this YouTube video http://www.youtube.com/watch?v=-Xl63aqWaTk (http://www.youtube.com/watch?v=-Xl63aqWaTk). If you
have one available, you can use a power drill to speed up the coil-winding process. You should ask an adult for help with
this step.
5. Finally, use your square of sandpaper to strip the enamel insulation off of roughly 3 cm segments at the end of
both wires that are sticking out of your coil.
a. If you do not know how to do this, refer to the Science Buddies Wire Stripping Tutorial. (http://youtu.be/Pd5QXDmvys)
Energy_p009_20140109.pdf
JAM-5220-KIT
Figure 9. The triangle symbol with a line at the tip represents a single LED. When multiple LEDs are all connected
facing the same direction, electrical current can flow through them. If just one LED is placed backwards, then
electrical current cannot flow at all.
Solderless breadboards provide a convenient way to quickly connect or remove electronic components in a circuit.
The small breadboard you are using in this science project has 17 rows of 10 holes each. Each row is split in half into
five columns. Each half-row of five holes is electrically connected inside the breadboard. This is what allows you to
connect the LEDs together, even though their leads are not touching. Figure 10 highlights each set of connected
holes with yellow rectangles:
Figure 10. Each half-row of the breadboard, consisting of five holes, is electrically connected.
Figure 8. Arrange six LEDs in a staggered row on the breadboard, as shown here. (Top) A photograph of the actual
breadboard. (Middle) A zoomed-in photo of the LED leads pressed into the breadboard holes. (Bottom) A top-down
diagram of the breadboard showing the LED lights (red circles) and the holes to place the LED leads into (the small, solid
gray circles). Remember to make sure all the longer LED leads are facing left, and all the shorter LED leads are facing
right.
This means that it does not actually matter how exactly you put the LEDs into the breadboard, as long as the leads of
each adjacent LED are connected to the same row on the breadboard (and the LEDs are all facing the same
direction). The three configurations in Figure 11 below all do the same thing electrically:
Technical Note: More about Breadboards and LEDs
This information is not essential to complete the science project; it is just provided for students who are interested in
learning more.
LED stands for light-emitting diode. A diode is like a one-way door for electricity—it only lets electrical current flow
through in one direction. "Light-emitting" diode means that LEDs will light up when electrical current flows through
them. Since LEDs act like one-way doors, that is why you must make sure all the LEDs are facing in the same
direction when you connect them. Otherwise they would prevent electrical current from flowing in either direction, and
would never light up. This is easy to see if you draw a circuit diagram for the LEDs. In circuit diagrams, LEDs are
represented by triangle symbols that show the direction electricity can flow, like in Figure 9:
Energy_p009_20140109.pdf
Figure 11. These three breadboard LED arrangements are all electrically equivalent. In each case, the leads of adjacent LEDs are
through rows in the breadboard (highlighted by the yellow rectangles).
2. Create a data table in your lab notebook, like Table 1, below:
JAM-5220-KIT
for troubleshooting tips.
Number of LEDs
Number of Magnets Needed to Light Up
1
Technical Note
The LED flickers because your generator creates alternating current (AC). This means that the electrical current
alternates between positive and negative as you shake the generator. Since current can only flow through LEDs in
one direction, the LED will only light up half of the time, and appears to flicker. Lighting up the LED continuously
would require additional circuitry to make direct current (DC).
2
3
4
5
6
Table 1. Data table for recording how many magnets are needed to light up different numbers of LEDs.
3. Use your alligator clips to connect the first LED to your coil form (which will function as a generator), as shown in
Figure 12.
a. With the breadboard facing you, as shown in Figure 12, clip the red alligator clip onto the left-hand (longer)
lead of the first LED. Clip the black alligator clip onto the right-hand (shorter) lead of the first LED or the lefthand (longer) lead of the second LED.
i. Remember that the right-hand lead of the first LED and the left-hand lead of the second LED are
electrically connected by the breadboard, so you can attach the alligator clip to either one.
b. Important: Make sure that the red and black alligator clips do not touch each other. This will create a short
circuit and will prevent your LED from lighting up.
c. Clip the other end of each alligator clip onto one end of the wire from your coil. Be sure to clip on to the
parts of the wire where you sanded off insulation.
5. Determine how many magnets are required to light one LED.
a. Now, take the magnets out of your generator and carefully remove one magnet from the stack of six. Set it
aside, away from the other magnets.
b. Put the stack of five magnets back inside your generator and shake it again. Does the LED still light up?
c. Keep removing magnets until the LED no longer lights up. What is the minimum number of magnets
required to light a single LED? Enter your result in the data table in your lab notebook.
6. Determine how many magnets are required to light two LEDs.
a. Move the black alligator clip from the short lead of the first LED (or the long lead of the second LED) to the
short lead of the second LED (or the long lead of the third LED), as shown in Figure 13. Leave the red
alligator clip in place.
b. Start over with all six magnets. Remove one magnet at a time, and test your generator until the LEDs no
longer light up. Record the minimum number of magnets required to light two LEDs in your data table.
Figure 13. In order to test two LEDs, leave the red alligator clip in place. Move the black alligator clip to the shorter
(right-hand) lead of the second LED.
Figure 12. Connect the first LED to your generator coil with alligator clips, as shown here.
4. Now, you are finally ready to test your generator.
a. Take your entire stack of six neodymium magnets and drop them inside the card stock tube of your
generator. Important: Remember to follow all the safety rules listed above for neodymium magnets.
b. Cover the ends of your generator with your thumb and fingers so the magnets do not fall out, and quickly
shake it back and forth (but be careful not to shake loose the wires or breadboard attached to it!). Try to
shake your generator at a consistent speed for all of your trials.
c. Does the LED light up? You should see the LED flicker as you shake the magnets inside the generator.
d. If the LED does not light up at all, look at the Help tab (http://www.sciencebuddies.org/science-fairprojects/project_ideas/Energy_p009.shtml#help)
Energy_p009_20140109.pdf
7. Repeat step 6 for three, four, five, and six LEDs.
a. Each time, move the black alligator clip to the shorter (right-hand) lead of the next LED (or the longer, lefthand lead of the LED after that), as shown in Figure 14.
b. Each time, start over with all six magnets, and remove one magnet at a time until the LEDs no longer light
up. Record the minimum required number of magnets in your data table.
c. Note: If you are having trouble getting the LEDs to light up, try flipping your magnets around. Sometimes
when you wind a 1,500-wrap coil by hand, it can become a bit lopsided, and the amount of electricity that is
generated will not be perfectly symmetric as you shake it back and forth. As a result, your magnets might
work better facing in one direction than in the other. So, if the LEDs do not light up at all, always flip the
magnets around and try again before you record results in your data table.
for troubleshooting tips.
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Science Fair Project Guide (http://www.sciencebuddies.org/science-fair-projects/project_guide_index.shtml)
Other Ideas Like This (http://www.sciencebuddies.org/science-fair-projects/search.shtml?v=solt&pi=Energy_p009)
Energy & Power Project Ideas (http://www.sciencebuddies.org/science-fair-projects/recommender_interest_area.php?ia=Energy)
My Favorites (http://www.sciencebuddies.org/science-fair-projects/recommender_show_favorites.php)
If you like this project, you might enjoy exploring these related careers:
Electrical & Electronics Engineer
Just as a potter forms clay, or a steel worker molds molten steel, electrical and
electronics engineers gather and shape electricity and use it to make products that
transmit power or transmit information. Electrical and electronics engineers may
specialize in one of the millions of products that make or use electricity, like cell phones,
electric motors, microwaves, medical instruments, airline navigation system, or
handheld games. Read more (http://www.sciencebuddies.org/science-fair-projects/science-engineering-careers/Elec_electricalandelectronicsengineer_c001.shtml)
Electrical Engineering Technician
Electrical engineering technicians help design, test, and manufacture electrical and
electronic equipment. These people are part of the team of engineers and research
scientists that keep our high-tech world going and moving forward. Read more
(http://www.sciencebuddies.org/science-fair-projects/science-engineeringcareers/Elec_electricalengineeringtechnician_c001.shtml)
Sustainability Specialist
Are you passionate about the environment? Do you like developing and implementing
new ideas? Do you enjoy talking with people about how humans impact nature? If these
things are true about you, then you may be the ideal candidate for a job as a
sustainability specialist. Sustainability specialists work in large and small corporations
and universities to design and execute energy and resource conservation programs that
reduce their employers' impact on the environment. This is a great career for people who enjoy working on teams, are
socially responsible, and like to get things done! Read more (http://www.sciencebuddies.org/science-fair-projects/science-engineeringcareers/EnvEng_sustainabilityspecialist_c001.shtml)
Figure 14. The black alligator clip connected to the third, fourth, fifth, and sixth LEDs (top left, top right, bottom left, and bottom right, respectivel
Electrician
8. When you have finished testing all six LEDs, analyze your results.
a. Make a graph of the data from your data table, putting the number of LEDs you tried to light up on the x-axis
and the number of magnets that were required to light up the LEDs on the y-axis.
b. Do you see a relationship between the number of magnets and the number of LEDs that you can light up?
What was your hypothesis about this relationship?
c. How can you explain your results? Does adding more magnets make a stronger magnetic field? Is there a
relationship between the strength of a magnetic field and the amount of electricity induced in the coil?
Electricians are the people who bring electricity to our homes, schools, businesses,
public spaces, and streets—lighting up our world, keeping the indoor temperature
comfortable, and powering TVs, computers, and all sorts of machines that make life
better. Electricians install and maintain the wiring and equipment that carries electricity,
and they also fix electrical machines. Read more (http://www.sciencebuddies.org/science-fairprojects/science-engineering-careers/Elec_electrician_c001.shtml)
Variations
Credits
If you have access to an oscilloscope, try using it to test your generator. What does the resulting waveform look
like, and how does it change with different numbers of magnets?
The simple generator in this science project can only instantaneously light an LED while you are shaking it—it
cannot store the energy for use later. Can you build a circuit to store the energy (http://www.creativescience.org.uk/gensimple2.html),
and even make your own shake-to-light flashlight?
Build a larger generator—either using more/bigger magnets, more wraps of wire, or both. How do these things
affect how much electricity is generated, or how many LEDs you can light?
Each individual LED requires a certain amount of voltage in order to light up. Whether the voltage required
changes when you hook up multiple LEDs depends on whether you connect them in series or in parallel. Research
series and parallel circuits, and use the number of LEDs to estimate the maximum voltage from your generator.
Ben Finio, PhD, Science Buddies
This science project is based on the "Shake-a-gen" by Dr. Jonathan Hare. Hare, J.P. (2002). Physics on a Shoestring:
The Shake-A-Gen. Journal of Physics Education, volume 37, p. 436-439.
Scotch® is a registered trademark of 3M.
Last edit date: 2014-01-10
Related Links
Energy_p009_20140109.pdf
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Contact Us
If you have purchased a kit for this project from Science Buddies, we are pleased to answer any question not addressed
by the FAQs on our site. Please email us at [email protected] (mailto:[email protected]?
subject=Shaking%20Up%20Some%20Energy)
after you have checked the Frequently Asked Questions for this PI at
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Energy_p009.shtml#help
In your email, please follow these instructions:
1. What is your Science Buddies kit order number?
2. Please describe how you need help as thoroughly as possible:
Examples
Good Question I'm trying to do Experimental Procedure step #5, "Scrape the insulation from the wire. . ." How do
I know when I've scraped enough?
Good Question I'm at Experimental Procedure step #7, "Move the magnet back and forth . . ." and the LED is not
lighting up.
Bad Question I don't understand the instructions. Help!
Energy_p009_20140109.pdf
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