Level: K to High School
Time involvement: 5 minutes elementary, longer for H.S.
Materials: Vacuum cleaner pressure outlet and hose and rubber ball. Air pressure will draw the ball into the core of the air stream because of reduced pressure in the stream. Visually amazing as the hose/blower is tipped the ball remains in the airstream up to about 30 degrees off center. Fun for kits to grab the ball out of the airstream or replace it.
Discussion: Known as the Bernoulli Effect, this principle simply states that as air moves faster the pressure will be reduced. This classical Physics principle explains how an airplane wing or a bird wing creates lift. A simple demonstration can be done with a sheet of paper by holding it next to your lower lip and blowing across the top surface. The sheet of paper will immediately rise up into the air stream! The Bernoulli effect is more thoroughly discussed in the companion demonstration: Flying Cups and Bernoulli.
Learn More: The Bernoulli Effect is a complex concept named after Daniel Bernoulli, (1700-1782) a Swiss mathematician. His mathematical predictions are born out in wind tunnel experiments and aircraft designs. Younger students can enjoy the demonstration without the science behind it. Older students can be challenged with the mathematical basis.