Please note that the TECH extension requires the use of a micro:bit! Link to micro:bit code (hex file)

Exploring Electromagnetism: Building and Testing Electromagnets

An electromagnet is a type of magnet that is created by passing an electric current through a coil of wire, which generates a magnetic field. Unlike permanent magnets, electromagnets can be turned on and off and their strength can be adjusted by changing the amount of electric current flowing through the wire or by altering the properties of the core material. 

In this lab, you will build a simple electromagnet and explore how different variables affect its strength.

Electromagnet: A magnet created by passing an electric current through a coil of wire.

Coil: A series of loops or turns of wire. Also called a “solenoid”.

Magnetic Field: The region around a magnet where magnetic forces can be felt

Core: The material inside the coil of wire that becomes magnetized when an electric current flows through the wire.

Materials:

- Thin gauge, coated copper wire

- Bolts, nails, or screws (various sizes)

- D size batteries

- AA batteries

- Paperclips or iron filings

- Tape & rubber bands

Safety Note:

- Electricity will be running through the coil and core. Allow the electromagnet to cool before making adjustments or dismantling the setup.

Part 1: Changing the Number of Coils

1. Scratch 1 cm of the coating off both ends of the copper wire.

2. Wind the wire around the core as many times as you can, leaving the ends free.

3. Tape the ends of the wire to the battery.

4. Test the strength of the electromagnet by seeing how many paperclips or iron filings it can pick up.

5. Record your observations.

6. Repeat steps 1-5 with a different number of wire coils (lots vs few).

We changed the number of wire coils from ____________ to ____________ and observed: 

Part 2: Changing the Size of the Core

1. Repeat steps 1-4 from Part 1.

2. Replace the core with a different size (nail vs bolt).

3. Test the strength of the electromagnet with the new core by seeing how many paperclips or iron filings it can pick up.

4. Record your observations.

We changed the size of the core from ____________ to ____________ and observed: 

Part 3: Changing the Size of the Battery

1. Repeat steps 1-4 from Part 1.

2. Replace the battery with a different size (AA vs D).

3. Test the strength of the electromagnet with the new battery size by seeing how many paperclips or iron filings it can pick up.

4. Record your observations.

We changed the size of the battery from ____________ to ____________ and observed: 

Discussion Questions:

1. What were your observations when changing the number of wire coils? How did it affect the strength of the electromagnet?

2. How did changing the size of the core impact the strength of the electromagnet?

3. What differences did you notice when using different battery sizes? How did it affect the electromagnet's performance?

EXTENSION: Pick one: Number of Coils, Core size, Battery size. Test your electromagnets using a micro:bit to MEASURE & RECORD the strength of the magnetic field produced in microteslas (uT). Record your data and make a bar graph of your measurements below:

Conclusion:

After sharing data with the class, discuss: What were the most significant factor(s) influencing electromagnet performance: Coils, Core, or Battery? How can this knowledge be applied to real-world scenarios?