Physics Demo Number: 153

Approximate Run Time: 3 min

Magnetic Field Lines of A Permanent Bar Magnet

Demo Description

A permanent Bar Magnet is enclosed in a transparent housing designed to be put on an overhead projector. Iron filings may then be sprinkled lightly in the plastic well formed by the magnet housing and their patterns observed.

Scientific Principles

• Magnetic Field Lines of a Bar Magnet

Equipment

• A transparent housing surrounding a dedicated bar magnet is placed on the overhead projector.

• A shaker of iron filings is used to provide little magnetic dipoles to align along field lines.

Equipment Location

• Kit (153) on [B-2-6]

Instructions

Iron filings may be sprinkled lightly over the plastic well formed by the Bar Magnet housing.

Subsequent light mechanical tapping ( parallel to the projector screen upon which the magnet assembly is residing) , will allow the filings to align themselves along the magnetic field lines. This alignment of the filings displays the nature of the field lines to the informed observer.

Writeup created by David A. Burba

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