photochemistry

How a Photon Is Created or Absorbed

Giles Henderson
Eastern Illinois University, Charleston, IL 61920

Robert C. Rittenhouse
Walla Walla College, College Place, WA 99324

John C. Wright and Jon L. Holmes
University of Wisconsin-Madison, Madison, WI 53706

Blueprint Photography by the Cyanotype Process

In this Activity, students prepare cyanotype paper and use it to "photograph" different items using sunlight. This Activity demonstrates catalysis of chemical reactions by ultraviolet (UV) light using one of the earliest photographic processes, the cyanotype process. It is useful as an introduction to the damaging effects of UV radiation on living organisms and the role of sunscreens.

Hydrogen and chlorine cannon

Hydrogen and chlorine gases can be mixed together without reacting, but when the mixture is struck with bright light, it reacts explosively.