Here'ssomething you don't see every day: 2,000 pingpong balls and 30 middle-school teachers floating around in zerogravity.

Thisweightless snapshot was taken in the skies aboveCincinnati/Northern Kentucky International Airport, to capture a momentwhenteachers were demonstrating Newton'slawsof motion for their students. [Photo: 2000 ping pongballs in zerogravity.]

Therecent zero gravity jaunt was part the WeightlessFlights of Discovery program, an effort to engage middle-schoolstudents inscience and math. Weightless Flights, in its fifth year, is led byaerospaceand defense firm Northrop Grumman.

Theteachers and ping pong balls achieved weightlessnessaboard a specially modified Boeing 727 operated by the ZeroGravity Corporation. After reaching a cruising altitude of24,000 feet(7,273 meters), the jet flies in a parabolic motion. It climbs at a45-degreeangle to 34,000 feet (10,303 meters), then levels off, flying in agentle arcfor 20 to 30 seconds.

Duringthis part of the flight, the centrifugal forceexerted on the plane and its passengers cancels out the force ofgravity, andping pong balls are free to float. Then the plane dives to theparabola'strough, where it can begin another climb, starting the process overagain.

TypicalZero Gravity outings complete 12 to 15 parabolasduring a flight, according to the company's website, delivering up to 8minutesof weightlessnessduringa 1- or 2-hour flight.

Aftertheir Sept. 14 trip, teachers planned to return totheir classrooms to discuss their experience ? and Newton's laws ? withtheirstudents. The kids may be jealous they didn't get a taste of zerogravity forthemselves, but at least they didn't have to help clean up all thoseping pongballs.