Bernoulli's Cheese Ball 

Material: 

bendable soda straw 

round cheese ball (Cheetos or Planters snack product) for each participant

  

 

Future Quicktime Movie and photos of the demo to go here!

Procedure:

Special Directions: 

Reverse the straw, putting the non-bendable tip in your mouth. Bend the straw upward, hold the cheese ball about 1" above the straw tip, and blow. The cheese ball will remain suspended above the straw for as long as you can blow. 

 

Safety Concerns: 

Plenty of straws to go around and extra cheese balls for eating will discourage students from using one another's straw or eating cheese balls that have fallen on the floor. 

Questions:

Can you "hold" a cheese ball in the air without touching it? 

Where does the cheese ball "ride"? Why? 

 

Science Concept: 

This demo is an illustration of Bernoulli's Principal where air pressure decreases as the speed of the gas increases. Air pressure over the top of the cheese ball begins at the top of the atmosphere as it presses down upon the layers or air below (approximately 15 pounds per square inch at sea level). As your fast moving breath blows up through the straw, it causes the air beneath the cheese ball to move faster and thus reduces the air pressure below the cheese ball. So greater air pressure above is pressing down on the cheese ball and reduced pressure below is giving it a lift, thus the cheese ball remains stable just above the straw (until you run out of breath). 

Physical Menu

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