An electrician usually uses a special tool to measure the current that flows through a wiring. The tool is called a multimeter and it is capable of measuring several properties of electric flow. In this experiment, you’ll get to build a simple type of meter that will also respond to the flow of current.
Things Required:
10 yards of 24 -gauge insulated copper wire
Wire strippers
Packaging tape
Sewing needle
Thread
Strong bar magnet
Juice can
“D” cell battery
Directions:
Strip several inches of insulation from both ends of the wire. Wrap this wire around the can into a tight coil, leaving about a foot of wire each end of the coil. Slip the coil off the can. Wrap several pieces packaging tape around the coil to secure its shape. Use a larger piece of tape to tape the coil onto a flat surface so that it may stand up.
Use the magnet to magnetize the sewing needle. Stroke the needle at least forty times in the same direction.
Tie a small length of thread around the middle of the needle so that it may balance. Tape the other end of the thread to the top of the wire coil; the magnetized needle should balance in the middle of the open space of the coil.
Touch the free ends of the wires to the positive and negative sides or the “D” cell battery. What happens? Switch the wires and touch the opposite sides of the cell. What happens now?
This Is What Happens:
When the wires were attached to the cell, electricity flowed through the coil. This movement of charge created a magnetic field. The magnetic field affected the magnetized needle, causing it to spin and change its pointing direction. When the wires were switched, the current flowed in the opposite direction. In response, the needle turned and pointed in the opposite direction.
