Why is, say, 20lb. paper called 20lb. paper?

Yep,

The second answer is correct.

Have a look here for more details.

http://www.theofficeguide.com/copy-paper/

There are also grades of smootheness and whiteness etc.

Paper can also be classified by how it is affected by humidity.

Who would have thought paper could be so interesting ?

(Well maybe it is'nt)

That could probably paintings, so long as the charcoal was once buried deep adequate that it could no longer decompose or in any other case oxidize, and become re-published. However, that's a ways, a ways, a ways from essentially the most rate-amazing or intelligent technique to minimize atmospheric CO2, specially on account that the charcoal in query was once all set, packaged, and transported to the client, utilising a abundant volume of fossil fuels or vigor derived from fossil fuels alongside the way in which. Biochar, then again (that is the identical common idea, however performed substantially extra sensibly and rate-easily) may be very promising. You must seem it up. edit: no longer an informed, I is also fallacious approximately how most probably charcoal is to oxidize within the absence of fireside. And biochar has advantages *except* sequestering carbon.

Ok I work in a corragator plant. And deal with rolls of paper of many different weights of paper. So this is how the paper industry comes up with this number 22lbs. Its how much a 1000 sq feet of that paper weighs. And to put a 1000 sq feet in perspective is a area of 32 x 32 feet. So if a 1000 sq feet of a paper weighs 33 lbs it will be called 32 lbs.

I believe it's the weight in pounds of a ream (500 pages)