Magnetism and distance

How does the strength of a magnetic field change as a magnet moves further away?

In this experiment we graph distance against magnetic field strength, and use that to understand proportionality and rates of change.

Equipment

• micro:bit and display-shield
• Any magnet
• Ruler (15cm+)

Learning overview

• How the strength of a magnetic field changes
• Proportionality and rates of change
• Graphing
• Scientific variables

Experiment setup

Select Real-time data

Select the magnetometer

Visualise magnetic field strength

Use the ruler to place the magnet at fixed distances of 1 to 10cm and measure its magnetic field strength.

Experiment questions

1. What is the independent variable in this experiment?
2. What is one control variable in this experiment?
3. Complete the distance vs magnetic field strength graph

Mangetic field strength vs Distance

Using the ruler place the magnet at fixed intervals (1cm, 2cm) away from the micro:bit and use MicroData to read its magnetic field strength.

4. What was the difference in magnetic field strength between 1cm and 2cm?
5. What was the difference in magnetic field strength between 2cm and 3cm?
6. As distance increases: Is the magnetic field strength changing at a more-than or less-than proportional rate?