EXPERIMENT 1

SOLIDS IN THE AIR

THINGS YOU NEED: Large coffee can. Shiny white cardboard or paper 10 inches by 20 inches. Petroleum jelly (such as Vaseline) asking or mending tape. Wood pole 4 feet long. Wood base 1½ feet by 1½ feet.

According to the U.S. Environmental Protection Agency, millions and millions of tons of man-made waste products are released into the air each year in this country. The main ingredients in these waste products are carbon monoxide, sulfur and nitrogen gases, hydrocarbons, and very small solid and liquid particles.

Now of this huge amount released, probably around a third of it falls back to the earth. Some of it is visible as dust, ash, and smoke.

Technicians need special equipment to measure and study this fallout. But you can still get a general impression of how much dirt is in the air in your area by doing this simple two- part experiment. The first part concerns the amount of dirt that settles from the air. The second part concerns the direction from which the wind is bringing that dirt.

In part one, the coffee can is positioned on a stand with the open end facing upward. The sides of the can and the height of the stand will help to keep out the ground dust. After assem-