Points and Picas are easier to break down. At least that is why I find them easier to use when I need a finer grid. Who wants to work with .7854 of an inch grid? ;^)

It is always easy to go back to inches if you need to because 12 picas make an inch, or 72 points make an inch.

So I hear! :)
And now I need a workbook.

And it is much easier than it was in the old days, when there were 72.27 points to the inch, just to mess things up.

Today, just think of a pica as a sixth of an inch and you will be fine.

You're lucky you're in north america.

The silly US system for measuring pages in inches will be handy if you're planning on using a point/pica grid because these measurements are compatible.

an inch is made up of 6 picas.

each pica is made up of 12 points.

each inch then contains 72 points.

Now, using points to measure the size of type goes back to when they used to have metal type for printing.

The total maximum size of the font (maybe used in a capital M or something) was the entire height of the size. a 12-point 'e' won't be 1/6 of an inch in height, because a lowercase 'e' doesn't take up the full height it could within the character set.

I am stuck here in Canada, and we're 100% metric, save our paper sizes thanks to america. I really really wish we could just have metric paper sizes, they make so much more sense.

Oh well, I guess I'll have to live in a world of measurements *not* based on a base-10 decimal system.

Jennifer, I think that the best is you start to visualize the measurement. You can build a ruler in quark or other app. of your choice. Just change the preferences to the measurement you want (i.e. picas or points) and, by duplicating lines you can make your ruller. 1 pica is 12 points. Make a 12 point square divided in 12 parts, then duplicate it (by the number, don't drag) until it reaches the size you want. Do you follow me? You can include lines thicker or thinner in it as seen in a typical rulers. When you have the artwork done, output to positive film, the result is a transparent ruler. You ruler.
I once confronted myself with this problem, but in my case I need to understand visually what is a inch. Now I know: 72 pts.

After you are done you can call it "The Jennifer Typometer"

Cheers

André

About.com actually has some exercises for working with points and picas (!)... here.

I also found this tutorial on the point system...

This article on "the three Ps" (Picas, Points, and Pixels) also looks interesting.

Ricardo, that's great tutorial. Actually 'show' how you can build you own typometer.

Beautiful!
Practical exercises, thanks so much guys. :)