Electromagnetism is one of the fundamental interactions that is in effect in nature. Electromagnetic forces are described through electromagnetic fields that is a combination of electric and magnetic fields. Both fields are produced by charges. Stationary charges produce electric fields while moving charges (or currents) produce magnetic fields.
In this experiment, we will be proving that an electrical current can produce magnetic fields. Not only that, we will also demonstrate that changes in the flow of the current can alter the direction of the magnetic field.
What you will need:
- 12 inch stiff wire
- Battery holder
- 6 pcs AA batteries
- 8 inch insulated wire
- 4 small compasses
- Cardboard box (with a flap top)
- Tape
What you have to do:
- Place the 6 batteries in the battery holder.
- Create a hole in the cardboard box flap top and another at the bottom. The holes should not be directly over each other. See illustration.
- Take the battery holder’s black wire and put it through the bottom hole of the box. This wire is the one connected to the negative end of the battery.
- Open the box and put the stiff wire through the hole in the top lid of the box.
- Wrap the black wire around the end of the stiff wire securely. Make sure that the metal of the wire is connected to the stiff wire. Tape them together.
- Close the box and make sure that the stiff wire straight and sticking out the box.
- Take the insulated wire and wrap it around the top of the stiff wire. Ensure that the contact of both wires are secure.
- Position the 4 compasses on top of the box so they surround the wire sticking out.
- Draw the compass and indicate where each of the arrows are pointing.
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Image courtesy of PhysicsCentral.org Take the insulated wire and touch it to the red wire of the batter holder. Look at the compasses and see how they react. Draw where the arrows are pointing.
- Draw the flow of the current (flowing from the red wire to the black wire) and place it beside your drawing of the compass.
- Remove the black wire connected to the stiff wire and replace it with the red wire. Take the black wire and let it touch the insulated wire. Draw the reaction of the compasses and their arrows. Draw the flow of the current (still from the red wire to the black wire) beside the drawing of the compass.
What you need to know:
The key to demonstrate the principles of electromagnetism, requires both electricity and magnetism. In this experiment, we used a compass to illustrate the relationship between currents (moving electric charges) and magnetic fields. When the wire is hooked to a battery, current will flow through it – from the positive to the negative of the battery. This current can create magnetic fields – as evidenced by the reaction of the compass as it is placed near the electrically charged wire.
Magnetic fields always flow in one direction: from north pole to the south pole. When the wires of the battery holder was exchanged, this changed the direction of the current flow. You should observe that as the flow of current changes, so does the magnetic field – which is indicated by where the arrow of the compasses are pointing.
