A Fan in the Air

Words in Use (Lesson 4)

• vapor
• eliminate
• villain
• dense
• utilize
• humid
• theory
• descend
• circulate
• enormous
• predict
• vanish

Read the following passage to see how the new words are used in it.
   
A Fan in the Air
Fog, tiny droplets of water vapor, is the villain of the airports. In an effort to eliminate dense fog from airports, weathermen utilize giant fans, nylon strings, and chemicals dropped from planes or shot upwards from strange machines on the ground. Nothing works as well, though, as a new weapon in the fight against fog: the helicopter. Researchers believe that if warm dry air above the fog could somehow be driven down into the humid blanket of fog, the droplets would evaporate, thus clearing the air. In a recent experiment to test their theory the researchers had a helicopter descend into the fog above barely visible* Smith Mountain Airport near Roanoke, Virginia. The blades of the helicopter caused the air to circulate downwards and an enormous hole in the clouds opened above the airport. Weathermen predict that with larger, more expensive* helicopters they will be able to make the thickest fog vanish.