Untitled Document

Physics Demo Number: 018

Approximate

Run Time: 5 min

Small Version of the Smoke Box For Plane Mirror and Refraction

Demo Description

One utilizes one half of the smoke box, a flat mirror and a tank of water to show the laws of ray reflection from a planar surface and of ray refraction on entering a different medium.

Scientific Principles

For a light ray impinging at a non-normal angle to a plane mirror, one finds that the incident and the reflected rays form equal angles with the normal to the mirror at the point of impingement and are contained in a plane along with the normal to the surface.
A light ray is refracted toward the normal when going from air to water.

Equipment

Half of smoke box
Water tank
Plane mirror
Laser
Soap

Equipment Location

[C-3-2]
[C-4-3] Kit(018)
From Kit(061) on [C-1-2]
[C-2-3]
[C-2-5]

Instructions

The left photo shows the smoke box half , water tank , and front surface mirror on the table top.

The right photo shows the open face of the smoke box turned down on the table top for operating mode of the demonstration.

One may make use of the newer diode laser assembly described in demo019, letting it free stand on top of the smoke box for a cleaner setup.