Electric current is the transition of electrons from one place to another. When electrons transit (when electric current flows), a magnetic field is generated in the surrounding area. Let’s perform a simple experiment that examines electric current flow, magnetic fields, magnetic force, and how they interact.
Materials/Tools you’ll need
Aluminum foil
1 x two-sided magnet with north/south polarities
1 x compass (use an inexpensive one as it may be damaged)
2 x alligator-clip wires
1 x dry battery (D-size battery preferred as it resists heat generation, though C- and AA-size batteries may also be used for shorter periods)
Adhesive cello-tape or similar
・Scissors
・Ruler
Electric current is the transition of electrons from one place to another. When electrons transit (when electric current flows), a magnetic field is generated in the surrounding area. Let’s perform a simple experiment that examines electric current flow, magnetic fields, magnetic force, and how they interact.
Materials/Tools you’ll need
Aluminum foil
1 x two-sided magnet with north/south polarities
1 x compass (use an inexpensive one as it may be damaged)
2 x alligator-clip wires
1 x dry battery (D-size battery preferred as it resists heat generation, though C- and AA-size batteries may also be used for shorter periods)
Adhesive cello-tape or similar
・Scissors
・Ruler
Cut a strip of aluminum foil about 1 cm wide. This strip of metallic material will be used to conduct a flow of electrons.
If you cut the strip of aluminum foil too wide, the results of our experiment will be more difficult to detect. The ideal width is between 1.0–1.5 cm. Use a ruler to measure if you need to.
Bend your strip of aluminum foil into an arched “Ω” shape, and then secure the feet of your arch to the desk with adhesive tape. Leave a few centimeters of foil sticking out past the taped area—we will need those in the next step.
Attach alligator-clip wires onto the ends of your foil strip. Then position a compass beneath the center of the arch.
Touch the end of one wire to the battery’s positive terminal. Then touch the end of the other wire to the negative battery terminal for a brief moment. Observe what happens to the needle inside the compass.
Do not contact the wire to the negative battery terminal for any longer than a few seconds, or it will generate heat and may become dangerous. Remove it as soon as you have observed the results of your experiment.
Did you see the magnetic needle move? It moved because a magnetic field was created when electrical current passed from the positive battery terminal, through the wire, through the foil, through the other wire, and into the negative battery terminal. The influence of electromagnetic energy caused the needle to move.
Next, put your compass to one side and place a magnet under the foil in the same way as you positioned the compass.
Keep the magnet and compass well separated, as the powerful magnet could damage the compass.
Touch the alligator clips against the battery terminals while observing the effect on the foil. If your experiment is set up correctly, the magnetic field surrounding the foil interacts with the magnet’s field, causing the foil to move. Try flipping over the magnet (reversing the north and south poles) and contact the wires on the battery terminals again. What happens to the foil?.
If there is too much of a gap between the magnet and the foil, the effect weakens. Arrange the foil arch so that the gap between the top of the magnet and the foil is about 1–2 cm.
First, we have to make a wire coil. Make your first wrap around the battery about 20 cm down from the end of the wire, and leave it hanging loose. Keep wrapping the wire around the battery until the strand width is about 2 cm. Then wind the wire back over the top of the first layer towards your starting point and repeat until you have about 20 cm of wire left.
If you start rolling the wire too tightly, it will be difficult to pull the battery out later. Wind with gentle pressure to begin with.
Be very careful when handling the enamel wire to avoid injury.
Gently pull the battery out of the coil with 20 cm of wire left from the other end. Twist both sides around the insides of the coil to keep its loops together. Leave a short length at each end of the wire. You can secure the coil into place with a piece of tape. Next, take your sandpaper and rub the ends of your wire (2–3 cm) to completely remove the insulation.
Fold the sandpaper like a sandwich and pinch the wire end inside between your forefinger and thumb. Pull outwards to the end of the wire about 20 times, adjusting the wire in the fold of the sandpaper to properly expose it to the grain.
Attach an alligator-clip wire to both ends of your coil. Then clip the opposite ends of your wires onto the legs (terminals) of the LED. Normally, we would have to make sure the positive and negative terminals are connected in the right way, but for this experiment, we don’t need to worry about the polarity.
Make a stack of neodymium magnets one on top of the other and rapidly move them in and out as close as you can to the center of the coil.
Swift magnet motion near the coil is the key to this experiment. It doesn’t matter if the magnet bumps into the coil, just concentrate on moving the magnet around as fast as you can.
Neodymium is a very strong type of magnet, and will slam together when placed near each other. If you have a finger in the way, it can get badly pinched. Naturally, magnets will attract iron, so be sure to keep any sharp iron objects away from your workspace.
If you move the magnet fast enough, electricity is generated. The electrons pass back and forth through the wire and LED device, illuminating it briefly when the magnet is moved towards or away from the coil.
If your LED did not light up, reverse the magnet’s orientation in your hand and try again.
Cut a strip of aluminum foil about 1 cm wide. This strip of metallic material will be used to conduct a flow of electrons.
If you cut the strip of aluminum foil too wide, the results of our experiment will be more difficult to detect. The ideal width is between 1.0–1.5 cm. Use a ruler to measure if you need to.
Bend your strip of aluminum foil into an arched “Ω” shape, and then secure the feet of your arch to the desk with adhesive tape. Leave a few centimeters of foil sticking out past the taped area—we will need those in the next step.
Attach alligator-clip wires onto the ends of your foil strip. Then position a compass beneath the center of the arch.
Touch the end of one wire to the battery’s positive terminal. Then touch the end of the other wire to the negative battery terminal for a brief moment. Observe what happens to the needle inside the compass.
Do not contact the wire to the negative battery terminal for any longer than a few seconds, or it will generate heat and may become dangerous. Remove it as soon as you have observed the results of your experiment.
Did you see the magnetic needle move? It moved because a magnetic field was created when electrical current passed from the positive battery terminal, through the wire, through the foil, through the other wire, and into the negative battery terminal. The influence of electromagnetic energy caused the needle to move.
Next, put your compass to one side and place a magnet under the foil in the same way as you positioned the compass.
Keep the magnet and compass well separated, as the powerful magnet could damage the compass.
Touch the alligator clips against the battery terminals while observing the effect on the foil. If your experiment is set up correctly, the magnetic field surrounding the foil interacts with the magnet’s field, causing the foil to move. Try flipping over the magnet (reversing the north and south poles) and contact the wires on the battery terminals again. What happens to the foil?
If there is too much of a gap between the magnet and the foil, the effect weakens. Arrange the foil arch so that the gap between the top of the magnet and the foil is about 1–2 cm.
If your aluminum foil did not move…
- Check the width of the foil strip. If it’s too wide (2 cm or more), cut a 1 cm-wide strip and try again.
- Check that the distance between the compass or magnet and the foil does not exceed 2 cm. Peel the taped feet off the desk, reshape the foil arch to properly accommodate the compass or magnet, and then tape the feet down again.
If your aluminum foil did not move…
- Check the width of the foil strip. If it’s too wide (2 cm or more), cut a 1 cm-wide strip and try again.
- Check that the distance between the compass or magnet and the foil does not exceed 2 cm. Peel the taped feet off the desk, reshape the foil arch to properly accommodate the compass or magnet, and then tape the feet down again.
Earth is a giant magnet surrounded by a geomagnetic field with north and south poles. Opposite poles attract each other. Since the magnetized compass needle has south polarity, it always points north. So how did we trick it to point somewhere else? When we touched the wires to the battery terminals, electrical current moved through the foil and created its own magnetic field. The compass needle pointed towards the pole of attraction within this field because the pole’s attractive power was stronger than Earth’s magnetic north. If the polarities in this magnetic field were reversed, the compass needle would point in the opposite direction.
Earth is a giant magnet surrounded by a geomagnetic field with north and south poles. Opposite poles attract each other. Since the magnetized compass needle has south polarity, it always points north. So how did we trick it to point somewhere else? When we touched the wires to the battery terminals, electrical current moved through the foil and created its own magnetic field. The compass needle pointed towards the pole of attraction within this field because the pole’s attractive power was stronger than Earth’s magnetic north. If the polarities in this magnetic field were reversed, the compass needle would point in the opposite direction.
The magnetic field created by current flowing through the foil interacted with the magnetic field created by the magnet. The direction of magnetic force is determined by the orientation of the poles within the magnetic field (and all magnetic fields have poles). Objects are pulled towards the pole with opposite polarity, while objects are pushed away from the pole with the same polarity. These forces interacted and caused the flow of electrons to be deflected from their path through the foil, making the material move and change shape. When the magnet was turned over, reversing the polarities of its magnetic field, magnetic force again acted on the electrons, this time forcing the foil to move in the opposite direction.
The magnetic field created by current flowing through the foil interacted with the magnetic field created by the magnet. The direction of magnetic force is determined by the orientation of the poles within the magnetic field (and all magnetic fields have poles). Objects are pulled towards the pole with opposite polarity, while objects are pushed away from the pole with the same polarity. These forces interacted and caused the flow of electrons to be deflected from their path through the foil, making the material move and change shape. When the magnet was turned over, reversing the polarities of its magnetic field, magnetic force again acted on the electrons, this time forcing the foil to move in the opposite direction.
- When electric current flows through a wire (or foil conductor), a magnetic field is generated around it.
- When electric current flows through a wire (or foil conductor), a magnetic field is generated around it.
- If a stack of two or three magnets were used in this experiment, do you think the magnetic force would grow stronger? Try it and see what happens!
- If the current is higher, the magnetic field gets stronger. Do you think more current will allow you to move foil of greater thickness? Find out!
- Observe the effects on the foil and compass needle when the direction of current flow is reversed (swap the alligator wires on the foil). What happens?
- If a stack of two or three magnets were used in this experiment, do you think the magnetic force would grow stronger? Try it and see what happens!
- If the current is higher, the magnetic field gets stronger. Do you think more current will allow you to move foil of greater thickness? Find out!
- Observe the effects on the foil and compass needle when the direction of current flow is reversed (swap the alligator wires on the foil). What happens?
If three batteries or more are used, current can increase to potentially dangerous levels, causing the batteries to generate heat and increasing the chance of an accident. Only use multiple batteries under adult supervision, and only close the circuit for very short periods.
If three batteries or more are used, current can increase to potentially dangerous levels, causing the batteries to generate heat and increasing the chance of an accident. Only use multiple batteries under adult supervision, and only close the circuit for very short periods.
Earth is a giant magnet surrounded by a geomagnetic field with north and south poles. Opposite poles attract each other. Since the magnetized compass needle has south polarity, it always points north. So how did we trick it to point somewhere else? When we touched the wires to the battery terminals, electrical current moved through the foil and created its own magnetic field. The compass needle pointed towards the pole of attraction within this field because the pole’s attractive power was stronger than Earth’s magnetic north. If the polarities in this magnetic field were reversed, the compass needle would point in the opposite direction.
The magnetic field created by current flowing through the foil interacted with the magnetic field created by the magnet. The direction of magnetic force is determined by the orientation of the poles within the magnetic field (and all magnetic fields have poles). Objects are pulled towards the pole with opposite polarity, while objects are pushed away from the pole with the same polarity. These forces interacted and caused the flow of electrons to be deflected from their path through the foil, making the material move and change shape. When the magnet was turned over, reversing the polarities of its magnetic field, magnetic force again acted on the electrons, this time forcing the foil to move in the opposite direction.
- When electric current flows through a wire (or foil conductor), a magnetic field is generated around it.
- If a stack of two or three magnets were used in this experiment, do you think the magnetic force would grow stronger?
Try it and see what happens! - If the current is higher, the magnetic field gets stronger. Do you think more current will allow you to move foil of greater thickness? Find out!
- Observe the effects on the foil and compass needle when the direction of current flow is reversed (swap the alligator wires on the foil). What happens?
If three batteries or more are used, current can increase to potentially dangerous levels, causing the batteries to generate heat and increasing the chance of an accident. Only use multiple batteries under adult supervision, and only close the circuit for very short periods.
- Contact the alligator-clip wires to the battery terminals only for a few seconds at a time. If the circuit is closed for longer periods, there is greater risk of excessive heat-generation, battery malfunction, and potential harm.
- Contact the alligator-clip wires to the battery terminals only for a few seconds at a time. If the circuit is closed for longer periods, there is greater risk of excessive heat-generation, battery malfunction, and potential harm.
