After the testing this week, 4th graders entered the science classroom to floating ping-pong balls. The kids asked, “What’s going on here?” Mrs. Brindley explained that  the floating ping-pong ball is a wonderful example of  Bernoulli’s principle. Bernoulli, an 18th-century Swiss mathematician, discovered something quite unusual about moving air. He found that the faster air flows over the surface of something, the less the air pushes on that surface (and so the lower its pressure). The fact that airplanes can fly can be explained by Bernoulli’s principle!