# www.HAGMOLEN.nl

New Orleans:

Ten-Minutes-Talk

###### January, 13 => 1.45
pm

# Abstract

### Exploring the Theory of the Rainbow

I will present two teaching aids,
which can help students explore the mathematical theory of the rainbow. An
interactive computer demo (in Cabri) enables the student to investigate the path
of rays of light in a raindrop for different indices of refraction. Then the
student can experiment with a spotlight, a cardboard screen and a spherical
bottle filled with water as a three-dimensional model of the raindrop. This
experiment is based on an idea of Marcel G. Minnaert (1893-1970) of Utrecht.
From here it is a small step to the explanation of the rainbow. The teaching
aids are part of my M.Sc. work in mathematics education, and they can be used at
early undergraduate level and in the mathematics and physics curriculum of the
final year of the Dutch highschools.

# The Ten-Minutes-Talk

The text: text.pdf

# CABRI-géometrè

Sheet of the raindrop: sheet1.pdf

Sheet of the angle: sheet2.pdf

Sheet of the maximum of the angle (arcsin):
sheet2a.pdf + arcsin.pdf

Sheet of some path of rays of light in a
raindrop: sheet3.pdf | sheet3a.pdf

Applet of the raindrop: applet1

Applet of the angle: applet2

# Experiment

Photo's of the experiment tools: sheet1.jpg

Another photo of the experiment tools
and a close-up of the spectrum: sheet2.jpg

Photo's of the first place of braking
the rays of light: sheet3.jpg

Photo's of the second place of braking
the rays of light: sheet4.jpg

Photo's of the third place of braking
the rays of light: sheet5.jpg