Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Air Rush Through Narrow Space 

Name: Low
Status: student
Grade: 9-12
Country: US
Date: Winter 2011-2012
Question:
Why does air tend to rush in a narrow corridor or a door?


Replies:
Hi Low,

Like the Venturi of a carburetor of the older cars where the air rushes through a narrow passage, the pressure is higher.

This is related to the relationship that Pressure = Force / Area. The cross section of the narrow passage has a smaller area. If we assume the force of the air is constant, then the relationship follows that the pressure is higher.

That's the essence of why the air rushes.

-Alex Viray

There is a simple "general" answer; however, the details may be much more complicated. Air will "rush", that is flow, from a region of high pressure to a region of low pressure. That is the easy part, always true. The more difficult part is why in any given set of conditions there is a pressure difference from one place to the other. It can be a temperature difference, a secondary flow of air -- for example a gust of wind -- and many other possible causes. But the common factor is a pressure difference that will tend to equalize causing the rush of air.

Vince Calder


Click here to return to the Engineering Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory