Electric motors allow us to empirically demonstrate interesting properties of electromagnetism. Although the principles underlying the phenomena of electric current and electromagnetism are rather technical, it is not difficult to build an elementary motor; you can make a very simple one using a coil of electrical wire, an electrical power source and a magnet.
Steps
Part 1 of 3: Winding the Bobbin
Step 1. Join four pencils with masking tape
Fasten them in groups of two to make a solid object around which you can wrap the coil; alternatively, you can use a cylinder with an approximate diameter of 1.5 cm.
Step 2. Wrap the electrical wire around the pencils
Once you have joined them together or found a suitable cylindrical object, start wrapping the electric wire tightly. Starting from the center, make fifteen turns moving towards one end and another fifteen towards the other. When finished, remove the core of pencils; in this way, you get a spool with two free ends.
Step 3. Wrap the loose ends around the coil
Bring them around each side three or four times to keep the structure compact; point the ends of the loose ends away from the roll.
Part 2 of 3: Connect the Battery
Step 1. Secure the battery
Use duct tape or plasticine to block the power source on a flat surface such as a desk or table. This step allows you to connect it to the coil without having to hold it still with your hands; make sure the battery is resting on its side for easy access to both terminals.
Step 2. Strip the ends of the electrical wire
Use a cable stripper and remove the insulating sheath from the free ends of the roll; these are connected to the battery and allow the electric current to flow through the coil. With this operation you can remove any coating applied to the copper wire.
Step 3. Thread each end through the eye of a needle
The needle is perfect for holding up electrical cables. Insert each stripped end into an eye; alternatively, you can use two folded staples (one for each free end) to make the support.
Step 4. Secure the needles to the battery terminals using tape
Once the electric cable is connected to both needles, you must connect them to the source of electricity; put one in contact with the positive pole (indicated with the "+" sign) and the other with the negative pole (indicated with the "-" sign).
- Make sure the needle tips are pointing down towards the battery and the eyes face up with the bobbin on top.
- Make sure that no needle is touching the respective poles of the battery.
- When the two free ends are connected to the battery, the electric energy passes through the needles and the cable; at this stage it is best to wear rubber or insulating gloves.
Part 3 of 3: Insert the Magnet
Step 1. Bring a magnet close to the coil
When the electric current flows through the winding, it will be able to interact with the magnet; bring the latter close to the reel or fix it to the battery itself, right under the reel, using adhesive tape. The closer the magnet is, the stronger the electromagnetic interaction will be.
Step 2. Spin the reel
Observe what happens when you turn it: depending on the direction in which the current flows and which side of the magnet is interacting with the winding, the latter may continue to turn or not. If the reel stops, spin it in the other direction.
Step 3. Experiment with different methods
Each variation leads to different results. The reel may spin faster, slower, or remain completely still, depending on the factor you have changed. Try moving the magnet closer or further away, using a stronger one, or having the other side interact with the coil. These alterations help to understand in a fun way the forces involved in an electric motor.
Advice
- This type of design is suitable for flat surfaces.
- To achieve good stability even at high speeds, you can make an oval-shaped engine.
Warnings
- If the project is being done by a child, make sure there is always adult supervision to avoid accidents.
- If you use a thin cable and a strong electrical current, the cable can get hot!
