Can you generate electricity for a flashlight without batteries?
Problem
One evening, at home doing homework, the power goes off in your
house. Your whole family is scrambling to find flashlights in the dark.
Unfortunately, the only flashlight you can find has a dead battery.
As you finish your homework by candlelight, you decide that there has
got to be a better way to power a light.
Your Mission
Using the materials provided, you must create a device that can
produce electricity.
Instructions
To begin building your generator, take a strip of cardstock and roll
it up along the long axis. Make sure the inner diameter is just a bit
larger than your magnets. Secure it with duct tape.
Take your magnet wire and tape the free end to one end of the tube
so it doesn’t come unraveled. With the loose end secured, begin
wrapping the magnet wire around the tube. Leave the lead of the
magnet wire exposed for testing.
When you are done, clip the winding from the spool and tape it to
the tube so it doesn’t come undone. Make sure the newly clipped
end is exposed just like the first end.
Scrape the enamel insulation off of both ends of the magnet wire.
Using two alligator clips, connect each terminal of the generator to
each probe of the multimeter.
Turn on your multimeter. We want to measure AC Voltage. This will
be indicated by VAC, or by the symbol on your multimeter.
Put the magnet in the tube and shake it back and forth to generate
AC current.
Watch the multimeter to see the voltage produced by your generator.
Hint
When a magnet moves through a coil of wire, electricity is produced in
the wire. How do you think the number of turns in the coil will affect the
amount of electricity generated?
How to Test
Instruct the students to create a generator. Make
sure they leave both leads of the magnet wire exposed
for testing.
Once the students are done, scrape the enamel insulation
off of both ends of the magnet wire for testing.
Using two alligator clip connectors, clip each terminal of
the generator to each probe of the multimeter.
Turn on your multimeter. We want to measure AC Voltage.
This will be indicated by VAC, or by the symbol on
your multimeter.
Have your students move their generators and watch
the multimeter for the highest voltage shown.
Example Solution
Take a 5″ by 7″ strip of cardstock and roll it up along
the long axis. Make sure the inner diameter is just a bit
larger than your magnets. Use duct tape to secure the
tube in place.
Take your magnet wire and tape the free end to one
end of the tube so it doesn’t come unraveled. With
the loose end secured, begin wrapping the magnet wire
around the tube.
When you’re done, clip the winding from the spool and
tape it to the tube so it doesn’t come undone. Make sure
the newly clipped end is exposed just like the first end.
After scratching off the enamel insulation from the two
exposed ends of magnet wire and connecting it to
the multimeter using alligator clips, put the magnet in the
tube and shake it back and forth to generate AC current.
Student Hint
When a magnet moves through a coil of wire, electricity is
produced in the wire. How do you think the number of turns
in the coil will affect the amount of electricity generated?
