Okay, how many Pounds per Square Inch does lead 'weigh', since that seems to be your measurement unit of choice?
Right. So let's put this block of lead and our scales in an airtight container, and remove all the air. How much does our lead block weigh now?
Suppose we instead had a sealed container full of air. Would it weigh more than a sealed container with nothing in it?
The air in the container is still adding pressure to the scale.
Ok, you know what?
I have better things to do than argue with you about air.
Have it your way, genius - I honestly don't give a damn.
Pounds per square inch is a measurement of _pressure_.
What are you asking for, knowledgekeeper? Its weight per unit volume at standard pressure and temperature (eg, water weighs 1 gram per cubic centimeter at STP), or something else?
How do you measure anything?
You measure it by using the force of it's pressure on an object such as a scale...
Air has a weight, weight is the force felt by an object under gravity: F=ma.
As air is made of particals it clearly has a mass (don't bring light into this).
Therefore it clearly has a weight.
However on earth what most people would think of as wait also factors in bouyancy, ie something would 'weigh' less under water than on land.
So as bouyancy can in effect be considered as the relationship between the mass of intrest and the mass of the surrounding medium. You could say that air is 'weightless' how ever this would be wrong, because the real deffinition of weight is not depended on bouyancy.
Air has a mass of 4.809x10^-26kg
as weight = ma and a on earth is 9.81ms^-2
The weight of air on earth is: 4.72x10^-25 N
...no it's not. Air has weight, just like everything else.
Yes it is, and without pressure, air is weightless.
Alright, how much does lead weigh, ichibanarky?
...which is measured by pressure...
14.7 pounds per square inch
Look up the density of air. You'll get some number in pounds per cubic foot, which tells you how many pounds of air is in a cubic foot of air. That's the definition of density: weight per volume.
And pressure is unrelated. Unless you mean the weight of the 80 mile column of air causing the pressure. I don't think anyone asking this question cares specifically about how much the 80 miles of air above them weighs.
weren't asked for mass.
here is a link to the explanation of the molecular mass of air.