Nick Kosikowski, age 10, of Dunwoody, Georgia, for his question:

Why do geese fly in a V formation?     

To us, the air seems like a filmy nothing. But flying birds know that it is full of secret twists and turns. They sense how its breezes and rising currents push and pull to help or hinder their flying. Plane designers study these things and streamline aircraft to take advantage of invisible currents. Flying, birds have used these secrets for ages. A flock of flying geese takes advantage of a very complicated V shaped pattern of streaming air.

They help to create it by letting a leader push his or her way through the air. This starts a V shaped pattern of currents fanning out behind. The streaming air makes flying easier for the other geese. But after a while the hard working leader grows tired and drops back in line. Then a volunteer moves up front to push through the air and start the V shaped currents that make flying easier for his friends.