Section 6 Magnetism and electromagnetism
Magnetic field lines can be plotted, and their direction determined, using a plotting compass.
- Put the plotting compass next to one of the poles, and draw a pencil dot where the compass points.
- Move the compass so that the tail end of the pointer aims at that dot.
- Again, draw a pencil dot where the compass points. Repeat until the compass returns to the other pole.
- Join up the dots.
- Add arrows to show that the eld points from the N pole to the S pole.
- Repeat for another starting point.
The field lines always have arrows from the N pole to the S pole and the lines never cross over each other or touch.
If two magnets are placed close together, their magnetic elds will interact. The magnetic eld pattern can be shown using iron lings or plotting compasses as above.
N.B. The same rules apply; the eld lines go from the N pole to the S pole and never cross or touch.