The Funnel and the Ball
Author(s): Aldo-Rafael Cos and Stacie Bailey
Discrepant Event - Teacher's Guide
SED 695B; Fall 2005

 
 
Detailed Explanation of Discrepant Event

Principles illustrated

  • The Bernoulli's principle states that differences in air pressure create lift.
 When fast moving air is present inside the funnel, it creates low pressure. The faster the air, the lower the pressure. That means that there is higher pressure outside the funnel. This higher pressure is what sucks the ball up the funnel and keeps it there. This difference in air pressure created by a speed differential is known as Bernoulli's principle.

Standards

  • 8th grade - Unbalanced forces cause changes in velocity.
 

Questioning Script

Prior knowledge & experience: Pushing objects results in the objects moving in the direction one pushes.

Root question: Why is the ball sucked up the tube when you blow through the tube?

Target response:

Common Misconceptions: Normally, when you blow on objects, the object moves in the direction you are blowing.

 
   

References & Links:

Science Inquiry