How do we do it? Volume.

Here's another fun exercise from this evening class on the science, nature, and philosophy of time that I'm taking. (The instructor attributes this to Nobel prize winning physicist Kip Thorne's 1994 book Black Holes & Time Warps.)

Get three meter sticks: that's a measuring stick like a yard stick, but it's one meter long, it's divided up into one hundred centimeters, and every centimeter is divided up into ten millimeters.

Lay the first stick down on the table. There are one thousand (1,000 or 10³) linear millimeters along the length defined by that stick.

Lay the second stick down on the table at a ninety degree angle to the first so that their corners touch. There are one million (1,000,000 or 10⁶) square millimeters in the area bordered by those two sticks.

Lay the third stick orthogonally so that it stands straight up from the table and its corner touches the corners of the first two sticks. There are one billion (1,000,000,000 or 10⁹) cubic millimeters in the volume bordered by those three sticks.

See, you thought a billion was big, didn't you? But here we are, with a billion easily measurable things just in the space on the table right in front of us.

(I was forced - FORCED, I tell you - to order three inexpensive wooden meter sticks from Amazon just so I can do this in real-life.)