```Comparison of Images Formed By Plane, Cylindrical (Concave Side), and
Spherical (Concave Side) Mirrors

Robert Tisdale  Julian H. S.
Levi Johnson    Otis Elementary
Alex Economou   C. V. S.

Objectives:

1) To distinguish between horizontal and vertical axes and to
recognize that ones eyes lie along a horizontal axis and ones
forehead and chin lie along a vertical axis.
2) To describe plane, cylindrical, and concave mirrors in terms of
curvature about horizontal and vertical axes.
3) To help students discover that image reversal occurs when the axis
of the object is parallel to the axis of curvature of the mirror,
and that no reversal occurs when the axis of the object is parallel
to a linear mirror axis.

This exercise can be done:
1) Anytime during the year as an attention grabber and an exercise in
observation and interpretation.
2) As an introduction to mirror images.
3) As a review of mirror images.

Apparatus needed:

Plane mirror, cylindrical mirror, short focal length concave mirror.

Notes: The cylindrical mirrors can be made by gluing a 10 cm by 10 cm
piece of aluminized mylar inside of a 120o section of carpet roll
tubing. In order to avoid confusion which is associated with left and
right when observing mirror images, it seems best to describe
orientation along the horizontal axis in terms of some objects in the
room, such as window side and door side.

Recommended strategy:

1) Beginning with the plane mirror ask the student to cover one eye
with their hand and observe the image of their face. Describe the
image as reversed or not reversed top to bottom, or window side to
door side. Turn the mirror through 90o and observe the image again.
2) Using the concave side of a cylindrical mirror repeat procedure