In: Physics
Supplies: aluminum foil, battery, tape
Safety warning. The foil will heat up and there will be very small sparks in this experiment. Keep it away from your face. Use a piece of cardboard under the experiment to keep from damaging surfaces.
Make the wires:
Cut two strips of aluminum foil about 15 cm long by 2 cm across. The dimensions do not matter greatly, it is all right to estimate.
Fold the two pieces in half and then in half again to make two long thin pieces of foil. Pull off a piece of tape a little bit shorter than the foil, and encase the foil in the tape. This will insulate your wire. Leave the ends exposed so you can make electrical contact at the ends. Do this to both pieces.
Gather any batteries you can find. You will need two 1.5 V batteries. Tape them together positive to negative so you will have an overall potential difference of 3 V. You can use more batteries for a more dramatic effect.
Should you connect the batteries in series or parallel to get the highest potential difference? Why?
Tape one of the aluminum foil wires to the positive end of the batteries and one to the negative end. Do not touch the wires together!!!!
Why should you not touch the wires together?
Now cut a small sliver of aluminum foil. Make it as thin as possible. Touch one wire to one end of the sliver and the other wire to the other end. You should see small sparks and the sliver should combust.
Theoretically how much current is going through the circuit when it is connected?
Why does the sliver combust?
Now cut a wider sliver. Connect it across the wires.
What happens when you connect the wider sliver? Why?
How does this relate to the fuses in your house or car?
If you were going to put a fuse in a circuit to protect a certain element, would you want the fuse in series or parallel to the element? Why?