This lab explores the physics, mathematics, and geometry of light and
optics. It leads the student through a series of questions,
experiments, and analysis in order to answer the question ``How are
rainbows formed?'' Along the way, students discover why rainbows only
occur when the sun is behind the observer, and they predict the angle
in the sky that a rainbow should appear if the location of the sun is
known. The investigation uses a series of analytical and geometric
questions based on a UMAP module by Steven Janke
[Janke],
but the real visual and numerical power of the lab is its interface to
the simulation of light of a given wavelength passing through a
spherical water droplet (see Figure 1). The data generated by this
simulation intimately connects the physical problem to its
mathematical formulation.

### Figure 1: Simulation of light rays passing through a water droplet.

**Next: **The Numerical Integration Lab

**Up: **Introduction

Frederick J. Wicklin <`fjw@geom.umn.edu`>

Last modified: Fri Nov 29 12:28:34 1996