How do you plot a magnetic field around a bar magnet?

To plot a magnetic field around a bar magnet, use iron filings or a small compass to trace field lines.

To start, place a bar magnet on a flat surface, such as a piece of paper. If you're using iron filings, sprinkle them evenly around the magnet. The filings will align themselves along the magnetic field lines, showing the pattern of the field. You'll notice that the filings form curved lines that extend from one pole of the magnet to the other, illustrating the direction of the magnetic field.

Alternatively, you can use a small compass to plot the magnetic field. Place the compass at various points around the magnet and mark the direction the needle points. The compass needle aligns with the magnetic field, pointing from the north pole to the south pole of the magnet. By moving the compass to different locations and marking the direction of the needle each time, you can draw the magnetic field lines on the paper.

The magnetic field lines will be denser near the poles of the magnet, indicating a stronger magnetic field in those areas. As you move further away from the magnet, the lines will spread out, showing that the magnetic field weakens with distance. Remember, the field lines never cross each other and always form closed loops, even though they may extend far away from the magnet.

This method helps you visualise the invisible magnetic field and understand how it interacts with other magnetic materials. It's a fundamental concept in GCSE Physics, illustrating the nature of magnetic forces and fields.