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CAUTION
Remember
these experiments involve only low voltage direct current,
this is not the same as household current. Never touch your
current detector or voltmeter to an outlet or to anything
connected to the outlet. This could result in a short, causing
injury or fire.
Experiment
1: The Lemon Battery
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For today’s science experiment, it’s possible to
make your own simple battery out of materials you find
around the house. You will need:
- 1 Lemon
- 1 Galvanized
Roofing Nail
- Heavy Copper
Wire
- Voltmeter
(see below)
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Steps
- Take a lemon.
Roll it on a table until it feels juicy inside.
- Insert a
galvanized roofing nail into the lemon.
- Insert a
piece of heavy copper wire into the lemon. Make
sure that the wire is close to, but not touching,
the nail.
In this case,
the zinc coating on the nail is the negative electrode
and the copper wire is the positive electrode. The
lemon juice, which is slightly acid (that’s why
it’s bitter), acts as the electrolyte. You have just
created a battery cell.
You can use a
voltmeter to measure the voltage of your cell
(inexpensive voltmeters are available at many
hardware, electronics, or electrical supply stores).
Touch the negative lead on the voltmeter to the nail
and the positive lead to the wire. It should read
nearly half a volt. If you take the nail out and
replace it with a paperclip, you will notice the
voltage will drop to about a third of a volt.
Click
here to download this experiment in Acrobat .pdf
format.
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Experiment
2: The Coin Battery
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If you would like to try another battery project, you
can reproduce essentially what Volta did back in 1800
that ultimately led to today's batteries.
You will need:
- 1 Glass of
Water
- Salt
- Paper Towel
- Pennies and
Dimes
- 1 Plate
- Voltmeter
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Steps
- Take a glass
of water and dissolve some salt in it. This
will be your electrolyte with the dissolved salt
providing the current carriers.
- Now take a
piece of paper towel and moisten it with the salt
water.
- Place a penny
on a plate, put a piece of paper towel on the
penny and then put a dime on top of the paper
towel.
Using your
voltmeter, you should be able to get a reading between
the penny and the dime. You have just made
another form of battery cell.
You can build a
series string by stacking another paper towel and
penny on top of the dime and then adding a paper towel
and dime as before. Make sure that the paper
towel separators do not touch each other. Now
your voltage reading should be double what it was
before. You can continue building the stack.
Each time you add another penny, paper towel, and dime
unit, the overall voltage will increase. If you
build a stack of 5 or so 'cells', moisten your
fingers, and pick up the stack. You might be
able to feel a slight tingle from the electricity.
Click
here to download this experiment in Acrobat .pdf
format.
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