The floating ball demo is an economical way to introduce students to Bernoulli's law.
The styrofoam ball will fly up with the air from the persons breath until it reaches a point of balance â this is where the force of gravity (which pushes the ball down) is equal to the force of the air (which is pushing the ball up).
The styrofoam ball stays within the column of air because of air pressure. The air coming from the tube is moving faster than the air around it, and this means that it also has a lower air pressure than the air around it. (We know this thanks to our old friend Bernoulli, who discovered this relationship back in the 1700âs). So the ball is kept within the column of lower air pressure because of the higher-pressure air surrounding it.