The Universe in the Classroom

Light Pollution


[This activity is based on one developed by Jerry Reed and extensively edited and amended by Dave Crawford.]


In this activity, students observe the design of outdoor lighting and discuss how this affects the efficiency and effectiveness of the job which the lighting is intended to do and the degree of light

pollution which occurs. More advanced students may also observe and describe the spectrum of the outdoor lighting and how that is related to the effectiveness of the lighting and to the degree of light pollution.

General Information

This activity can be done at the grade 6-12 level. Students at the grade 9-12 level may have been introduced to light and spectra in their science courses, and this activity is a good application. It is safer and more interesting and effective if students work in small groups. The activity can be completed in one or two evenings, plus a class period for discussion. It effectively integrates science and technology.

Background Information

Most of us are vaguely aware of lighting in our environment, but how often have we looked closely at lighting fixtures (even those in our own back yard)? We may have noticed deficiencies in lighting, but not investigated their cause.

Research has shown that many students have deep-seated misconceptions about light and lighting. What happens when yellow light shines on a blue car in a dark parking lot? Can you see a mirror or a bicycle reflector in a completely darkened room? Does light from a given source travel further at night than during the daytime? This activity is useful for dealing with such questions.

What the Students Will Do

Doing the Activity

1. Go outdoors in front of your house during the evening, and look at your block or the area visible from your home. Make a diagram of your block (or area).

2. Observe all the lights — the lights at your house, at your neighbors' houses, on the street, and any others visible to you. Note every one of the them by recording each light's approximate location on your diagram, record what kind of light it is (porch light, security light, street light, decorative yard light, flood light illuminating a tree, etc.), and try to identify the type of lamp. Mercury vapor lamps are a coldish white. High-pressure sodium lamps are pinkish or amber. Low-pressure sodium lamps are bright yellow. Incandescent lamps are a yellowish white.

3. [Optional] Use a spectroscope or diffraction grating to analyze the spectrum and identify the type of lamps you observe (as in Activity 2).

4. Note the following about the lights you observe:


The evaluation should be based on the reports kept by the students, including their ability to record and fully describe the light sources in their neighborhoods.


The students will become aware of the different types of lighting in their neighborhoods and how well each type of light does its job.

Koyaanisqatsi — Life Out of Balance

The Hopi Indians have a fine word, one that does not exist in English or any other language. It expresses a concept that is so evident in the modern world. It is koyaanisqatsi. One translation is "life out of balance." Others are "crazy life,"  or "life in turmoil," or "life disintegrating," or "a state of life that calls for another way of living."

Descriptions often make better definitions. One such is "A Los Angeles freeway at 4:00 p.m. on a Friday afternoon." Light pollution is another. The environmental problems we all live with, and which are growing daily, are all excellent examples of koyaanisqatsi.

An Example: The Light Pollution Project in the Schools in Greece

Margarita Metaxa

Arsakeio School of Athens and National Observatory of Athens

The light pollution project in the schools of Greece has been organized through the Greek Ministry of Education and Religion, with funding and support from the "Action III" initiative of the European Community. It began in 1997 and will culminate with a major symposium in Athens on 7-9 May 1999. The project was proposed by the Astrolaboratory of the Second Lyceum of the Arsakeio School of Athens (one of a family of high schools operated by a non-profit organization in Greece), in partnership with two other schools — one in Ioannina, Greece, and one in Manchester, U.K.

The objectives of the project are: (1) to familiarize students (and teachers!) with the scientific and technical aspects of light pollution through a study of astronomy, physics, computer science, and related topics; (2) to expose the students to the cultural and social dimensions of light pollution; and (3) to encourage students to understand and appreciate the effects of light pollution on their heritage and environment.

For maximum effectiveness, the students work in four groups:

The students who participate in this project receive valuable experience working and collaborating in groups and in taking initiatives, which will enable them to become active decision-makers in the future.

In addition to the three partner schools, a total of 40 schools — 32 in Greece and 8 from abroad, with 76 teachers and 690 students — have joined the project. In 18 Greek cities, local light pollution centers have been organized. These promote efficient, effective lighting in their local areas. In the city of Tarrega, Spain, a light pollution by-law has been passed as a result of the project. Many other organizations and individuals have contributed to the success of the project: the scientific advisory committee, the International Dark-Sky Association, the lighting companies Siemens and Philips Hellas SA, the municipalities in Greece which co-operated with the project, and the individuals who prepared scientific information for the project's web pages.

Much has been learned from the project already. Obviously, light and air pollution have robbed our towns and cities, both large and small, of the beauty of the night sky. Even so, most students, teachers, and the general public are totally unaware of the important and impressive environmental issue of light pollution. The strategy of having students work in four groups has proven to be very effective, as demonstrated by the excellent presentations and posters which were given at meetings held in Athens, Crete, and Manchester at the end of the project's first year.

In addition to the observatories, universities, lighting companies, schools, municipalities, and scientific and educational organizations who are already co-operating with the project, others are welcome to join. The best way to find out more and to register is through the project's web site at



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