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# Physics/Physics

Question
What is the diameter of air molecule in 30 X 40 X 20 ft room?

If I did this part right, I figured it is 24,000 cubic feet which equals approximately 679.605 cubic meters.

Thank you!

There seem to be two separate questions here.  First, the diameter of an air molecule.  Since molecules are not spherical, that doesn't really apply.  Most molecules in air are diatomic, so shaped a bit like a peanut shell.  The radii of the atoms that make up these molecules are about 0.1 nm (or 10^-10 meters).  http://hypertextbook.com/facts/MichaelPhillip.shtml

That does not depend on the dimensions of the room in which the atoms/molecules are contained in any way, leading to my confusing about you asking the diameter of an air molecule and then giving me numbers which are unrelated.  Are you asking about the volume of the room?  You did that right (though you have a few too many significant figures), if that's what you're asking.  Are you asking about a sphere with the same volume?  The volume of a sphere is given by (4/3)*pi*r^3, meaning that a sphere with r=5.5 m^3 would give you that volume.  But you gave me dimensions of a rectangle, so that makes no sense, either.

Perhaps if you told me why you were asking this I could actually answer the question, because I could rephrase it to be the question you really need answered.

Physics

Volunteer

#### Dr. Stephen O. Nelson

##### Expertise

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.

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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.

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