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Faraday's Magnetic Field Induction Experiment
Why is it when a magnet is moved in the direction of a copper wire coil, a current can then be measured in
the coil?
Following Oersted's discovery that an electric current produces a magnetic field around a wire, the English
scientist Michael Faraday showed in 1831 that a magnetic field could in effect produce an electric current.
In particular, he showed that a changing magnetic field could induce current in a coil. The creation of such
a current is called Electromagnetic Induction.
Faraday's Induction Experiment
Figure1 demonstrates what happens when a magnet is moved in relation to a coil. The North Pole of the
magnet provides a changing magnetic field at the face of the coil - but only so long as the magnet is
moving. When the magnet is stationary, no current flows in the coil. Note, the movement of the magnet in
different directions (towards and away) results in current flowing in corresponding opposite directions. If
the experiment is turned around so that this time the magnet is stationary but the coil is moved, again
current is observed to flow as before.
What is important to create an induced current is a changing magnetic field due to the relative motion
between the magnet and the coil. Moreover, it is observed that the larger and the faster the change, the
greater will be the size of the current.
Read more at Suite101: Electromagnetic Induction: Michael Faraday's Famous Experiment of Inducing
Current in a Coil | Suite101.com http://harry-p-schlanger.suite101.com/magnetic-inductiona57902#ixzz1eNVRmZyK
Volta battery
CKit has tools and materials
Constructing a Simple Voltaic Pile
Alessandro Volta discovered that when copper and zinc are connected with a conducting liquid, a wire that
connects the two will register a voltage. You can replicate Volta's original experiments by using a zinc
electrode and a copper electrode. The two electrodes should be submerged in a bath of saltwater or
something acidic like lemon juice. If you have a voltage meter, turn it down to its most sensitive DC setting
--- generally 10 volts or less. Connect the negative probe to the zinc electrode and the positive probe to
the copper electrode. The needle on the voltage meter will move to indicate the voltage that is being
generated by the voltaic pile.
(will try, but probably just use the above one)
Recreating Volta's Battery
Volta's battery was much more complex than the voltaic pile. You can recreate it by using thin plates of
copper and zinc in equal number. Alternate the plates of copper and zinc, separating them with layers of
cardboard. When you run out of plates, wrap a line of electrical tape around the contraption to bind it
together and then dunk it in salty water until the cardboard becomes soaked. Take two pieces of wire and
connect one to each end carefully. If you measure the voltage by touching the wires to the probes of a
voltmeter, you can see that this battery generates much more power than one using only two electrodes.
You can then perform simple nineteenth-century experiments, such as immersing the ends of the wires in
saltwater --- the bubbles that form are hydrogen and oxygen created as the water molecules are split by
the electricity.
Read more: School Projects on Voltaic Piles | eHow.com http://www.ehow.com/info_7934884_school-projects-voltaicpiles.html#ixzz1duEl4Lbs
Light bulb like Edison
In this activity, you will be creating a partial vacuum in a jar. The better the vacuum, the longer the
filament will glow before burning out.
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A 1 quart jar with tight fitting lid (such as a mayonnaise, peanut butter, or canning jar)
Masking tape
Scissors
A small nail and hammer
Small gauge electrical wire (about 1 meter)
Lamp wire
One 6-volt battery
Birthday candles
Small amount of modeling clay
Use the a nail to punch 2 small holes in the lid of the jar, about 5 cm apart. Strip off the insulation from the
ends of each wire using a pair of scissors. Run one end of each wire through the lid of the jar, so that they
extend to about the middle of jar when the lid is on. Use tape to tightly plug the holes in the jar lid. Attach
the end of one wire to one terminal on the 6-volt battery.
Now you need to add the filament. Remove a single strand of wire from lamp wire, about 4 cm long. Wind
the wire around the nail to make a coil, noting the number of coils. Then carefully remove the coil from the
nail and connect it to the two ends of the wire attached to the lid. Now, you are ready to test your first
light bulb.
The light bulb operator touches the unattached wire to the remaining battery terminal. Keep contact until
the filament burns out, or until 10 seconds have passed. (If your light bulb is too successful, you will drain
the battery).
In this experiment, you will use a lit candle as a means of creating a vacuum in the jar. How do you think a
vacuum will affect the longevity of your filament? Using the data collected in the first experiment, select a
filament length that burned for about 5 seconds. Prepare at least 5 of these filaments for use later.
Use the modeling clay to make a base for the birthday candle and place the candle in the jar. Place it off to
the side so as not to interfere with the filament. Now, light the candle and quickly, tightly screw the lid on
the jar. When the candle goes out, a partial vacuum is created. How long did the filament burn now?
Record your results. How has a vacuum affected the duration of the filament's burn?
http://www.gelighting.com/na/home_lighting/gela/teachers/lessons_history.htm