Printing magnetic field images from iron filings

What is it about?

Around 1900, many science and physics students made magnetic field images by capturing blueprints or iron gall ink prints of iron filings around a magnet. The article explains how to do it, and why. These methods are easy, convincing and interactive.

Featured Image

Why is it important?

Many students today plot magnetic fields using a small compass. That method is too difficult for beginners, limits interaction to just one tiny spot at a time instead of the whole field, and commonly produces very misleading diagrams. Returning to the older method overcomes these problems.