College of Liberal Arts & Sciences
2C20.23 - Coanda Effect - Bernoulli Bags
Code Number:
2C20.23
Demo Title:
Coanda Effect - Bernoulli Bags
Condition:
Good
Principle:
Bernoulli's Principle
Area of Study:
Heat & Fluids
Equipment:
8 foot Bernoulli Bag.
Procedure:
The bags come with both ends open. Tie one end closed and then ask a member of the class to try to blow up the bag with one breath. If they insert their mouth into the opening of the bag they will not be able to do so. However, if they blow into the bag from a distance of 1 foot from the opening they can easily blow up the bag with one breath.
A cool variation of this is to use a cardboard tube and soap bubble solution. Have the largest students see who can blow the biggest bubble by blowing directly into the tube. Then show that the smallest child can beat this if they hold the tube about 4 inches from their mouth when they blow into the tube.
Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist. The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose. The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources. Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks. These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage. Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.