Magnetic Field Demonstrator, 1 Each

The Magnetic Field Demonstrator by United Scientific is a transparent acrylic case, 8" x 4½" x ⅜", holding iron filings suspended in mineral oil. Placed over a magnet, it shows the field pattern directly, and it can be set on an overhead projector for whole-class viewing. Physics teachers use it to visualize field lines without the mess of loose iron filings.