Demonstration of Bernoulli's

Have a look at the movie of the ball in the air stream by clicking in the diagram below.. Suggest why the ball hovers at the same height all the time? Identify where the low and high pressures around the ball are located. Identify all the forces acting on the ball and mention how they balance each other.
The ball will oscillate from side to side as one side moves across the fast flowing air and is pushed back as shown below.

Explanation of how a sphere can be trapped in an air stream. Click to see a 400kb movie of this phenomenon.
Bernoulli was a French scientist who observed that when air flowed quickly past an object it created an area of low pressure. He tested his theory and came up with the law stating that “Fast flowing air creates areas of low pressure while slow flowing air creates high pressure”. This law can be observed in action in the movie above. The air flowing over the curved surfaces of the ball creates areas of relative low and high pressures. High pressures push the ball into the relative low pressure.