Murphy and Zollman: AAPT S2009 poster

An Apparatus for Investigating the Magnetic Field due to a Wire

Sytil Murphy and Dean Zollman

A new apparatus has been developed for exploring the magnetic field due to a wire. The apparatus is made of clear Plexiglas with a wire running through a triangular channel. The wire is connected to a battery and a switch. A compass can be used to detect the strength and direction of the magnetic field due to the wire and, because the apparatus is clear, compasses placed above and below the wire can be viewed simultaneously. When the switch is tapped, a compass placed above or below the wire may deflect depending on the orientation of the apparatus relative to an external magnetic field. Using the compass as a detector, the direction and strength of the magnetic field due to the wire can be investigated. In addition, the apparatus can be used to investigate the resonance frequency of a compass in a magnetic field.

Murphy: 2009 AAPT Apparatus Competition

Investigating the effect of the magnetic field from a wire on a compass

Sytil Murphy

This apparatus has two primary applications. The first is in teaching the concepts of resonance in the context of magnetism, which can be applied to the teaching and understanding of magnetic resonance imaging. The second investigates the direction of the field around a current carrying wire and the superposition of magnetic fields. The compass deflection angle can be measured as a function of the distance from the wire and compared to theory.