The air moves around the ball to create a pocket around the ball of low pressure air.
http://littleshop.physics.colostate.edu/onlineexperiments/Bernoulli.html
To illustrate the change in water surface tension when a detergent is added.
http://129.93.84.115/Chemistry/DoChem/DoChem068.html
Test the buoyancy of an aluminum foil boat and an aluminum foil ball.
http://www.tryscience.org/experiments/experiments_boats_athome.html