Physics Demo Number: 145

Approximate

Run Time: 5 min

Laser Beam in Air Seen by Scattering

Demo Description

Laser light is seen in air only if there are scattering centers.

Scientific Principles

• One must provide scattering centers to observe laser light in air.

Equipment

• Laser Ray Box

• Individual Laser

• Chalk Dust or Smoke Box

Equipment Location

• Laser Ray Box in Kit (090) in [C-3-2]

• 5 mW Laser in [C-2-4]

Instructions

One may lay the Laser Ray Box on the lecture table and proceed to scatter chalk dust in the beams to make them visible.

The result for the beam passing through a diverging lens inside a smoke box is seen in photo two:

Of course one may also use one of the He-Ne lasers to give a more intense single beam.

Writeup created by David A. Burba

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