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Physics/Bernoulli's Principle


Hello Mr. Nelson

I have a question about the Bernoulli's Principle. I'm using this source for a science project:

My question that I do not get is:

1. When air is blown between two objects, why is the air pressure exerted by it lower than the surrounding stationary air?

This page explains it well, and it's a citeable, academic resource.

Basically, all molecules in a fluid share energy evenly.  In very simple terms, if more of their kinetic energy is directed along a surface, less is perpendicular to the surface (causing collisions and pressure).  Therefore, fluids moving along a surface have molecules which have been deflected (on average) to collide with the surface less, and they exert less pressure.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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