EXPERIMENT 4

AN ELECTRICAL SMOKE TRAP

THINGS YOU NEED: Wood base 6 inches by 6 inches. Wood support 14 inches long. Cardboard tube 1½ inches in diameter and 1 foot long (such as from a roll of paper towels). Aluminum foil 6 inches by 6 inches. 2 toothpicks. Fresh &volt lantern battery. 9 feet of bell or hook-up wire. Knife switch. Type F-7996 induction coil or Ford Model “T” spark coil.*

One way that some industrial firms have been fighting airpollution is through the use of electrostatic precipitators. These devices capture smoke, dust, and liquid particles before they have a chance to go up the chimney into the atmosphere.

In general, electrostatic precipitators work as follows: Onthe way to the chimney, smoke and other wastes are channeledpast wires and plates that are oppositely charged at highvoltage. The particles receive a negative charge from the wires.

As a result, they are attracted to the positively charged plates. This action not only keeps pollution down, but it recovers useful by-products too.

Electric utility companies have been using such devices for decades. In fact, the first full-scale application of an electrostatic precipitator in the U.S. was made by The Detroit Edison Company in 1923. That was only a few years after its development, in 1910, by an American chemist named Frederick Gardner Cottrell.

For the F-7996 coil: Pontiac Coil, Inc., 5385 Perry Dr., Waterford, MI 48329 (phone 1-313-674-0456). For the Ford coil: Class-Tech Corp., 1400 Arboretum Blvd., Victoria, MN 55386 (phone l-800-874-9981). Each coil costs $30 postpaid. Mention that you are a student.>