TITLE: Laws of Reflection
AUTHOR: Douglas Vulcan, Florence Carlton Jr. High;
Florence, MT
GRADE LEVEL: 7 - 9
OVERVIEW: Teaching Laws of reflection to Jr High
students presented a problem to me until I started to
use this activity. Students develop the Laws of
Refection by use of their own experimentation and
observation. I give them as little help as possible
making them come up with something that will work. The
student must write in report form what ever procedure
and conclusions that come from the activity.
PURPOSE: To develop the basic Laws of Reflection by
observation of images of objects in plane mirrors.
RESOURCES/MATERIALS:
20 cm by 30 cm piece of card board ( to stick pins
into), dissecting pins, small plane mirrors, clay (for
mirror supports), protractors, rulers, and clear sheets
of paper.
ACTIVITIES AND PROCEDURES:
I let the students develop their own experiments.
(These are suggested steps to follow)
1. draw a line across the center of a sheet of paper
this becomes the reflective line in the
experiment.
2. place this sheet of paper on the piece of
cardboard.
3. place the mirror upright along the line on the
paper support with clay or other type of mirror
support
4. place two dissecting pins in front of the mirror.
One of the pins becomes the object the other the
observer pin.
5. while observing the image of the first pin rotate
the card board so that the image and the second
pin are in line with each other.
6. make marks on the paper along the line of sight
between the two. "image and observer"
7. remove the paper from the card board, mark the
lines of sight with a ruler, and measure the
angles formed.
8. repeat the experiment placing the pins in new
location
9. compare the angles in each trial.
TYING IT ALL TOGETHER: This one experiment can start
one off on a whole series of experiments about plane
mirrors. I usually ask the students to come up with a
statement about how far behind the mirror is the image.
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John Kurilecjmk@ofcn.org