Laser beams pass through various lenses in the smoke box.
A converging lens is moved on the optical bench until a sharp
image is formed. With a diverging lens there is no image.
A large uncorrected plano-convex lens for display purposes.
Shows that the effect of a lens depends on its density relative
to the surrounding medium as well as the shape of the lens. A
double concave hollow lens is placed in water and is seen to be
convergent.
Lenses on an optical bench are positioned to serve as a microscope.
Lenses on an optical bench are positioned to serve as a telescope.
Two lenses look like the traditional detective's magnifying glass,
but only one magnifies. The other produces an image smaller than
the object size.
Various mirrors are placed in the smoke box and reflect laser
beams.
Shows that an image in a plane mirror is reversed left to right
compared to the object.
A concave mirror is moved on the optical bench until a sharp image
is formed. A convex mirror does not form an image.
Shades in front of a plane mirror are adjusted until the subject
can just see its entire reflection. The exposed portion of the
mirror is half the height of the subject.
A trick with a mirror: a light bulb is reflected so that it appears
to be in a socket that is really empty.
Shows that two plane mirrors at right angles with their edges
in contact form a repetitive image identical with the object.
Objects inside a mirrored container appear to float just above
the container.
Heat from an electric heater is reflected from a spherical mirror
to another mirror that focuses the heat on a match which lights.
Mirrors create images of objects that do not exist.
White light is bent when passing from air to water.
White light is directed upward through water; some of the beam
is transmitted and some is reflected from the surface. At the
critical angle, there is no transmission: all of the beam is reflected.
A coiled plastic rod with a 90-degree bend transmits light directed
into an end.
A laser beam shining along a stream of water remains in the stream
as the water falls, turning the water red.
A laser beam is aimed through a long tank containing a gradient
in the index of refraction (a sugar solution.) The beam is bent
downwards and "bounces" off the bottom of the tank.
WARNING: Long preparation, advance notice required.
A laser beam is acoustically modulated and transmits an audio
signal to an amplifier and speaker.
Take a picture with a pinhole camera.
Two blocks of paraffin are separated by a sheet of tin foil.
Two lamps of different intensity are directed at the paraffin,
one on each side. The lamps are moved until both blocks of
paraffin have the same brightness. The ratio of the distances
between the lamps and paraffin gives the relative intensity of
the two lamps.
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