My wife looks at computers like buildings.

"A room is like kilo. That's one thousand. That's like the number of things in a small picture."

So far, so good. A small photo might be 2000 bytes or 2 kb in a email format or a fast-loading logo on a web site.

"If I take a really complicated photo, that's like a hotel with one thousand rooms. It becomes mega. That's a million of those pieces."

Great analogy. Some of these 5-megapixel cameras create photos that are 2000 kilobytes or 2 million bytes or 2 megabytes.

"So I guess Giga must be REALLY big, so it's like a city of hotels or skyscrapers."

Well done! A gigabyte is indeed one thousand megabytes or one thousand times one million. A DVD with 4 Gigs (4000 megabytes) can store 200 short videos from a cruise. Or 2000 photos that are 2 megabytes each. And that should be enough space for this traveler's videos! I'd have to take 250 cruises to reach a terabyte of videos.

As a math teacher, I look for these sorts of scales to show my students that girls can do math, too. Being able to talk "computer" means more than saying "Here's a hard drive and it's connected to a CPU." It also means knowing the scale of speed (kilohertz or megahertz?) and size of storage (megabytes or gigabytes?). It means room - skyscraper - city, the way my wife is starting to see the world of kilo - mega - giga. And a world with a thousand cities (tera) certainly will need to cover La Tierra (which is a way of thinking about one trillion).

What's after that? It's the fifth in the series, so it's like "penta"... but it's called "peta": I'm not ready for a petabyte of space!
The following measurements come from http://www.cleavebooks.co.uk/dictunit/notesp.htm

peta P = 10^15 = 1 000 000 000 000 000 (quadrillion)
tera T = 10^12 = 1 000 000 000 000 (trillion)
giga G = 10^9 = 1 000 000 000 (billion)
mega M = 10^6 = 1 000 000
kilo k = 10^3 = 1 000

deci d = 10^-1 = 0.1
centi c = 10^-2 = 0.01
milli m = 10^-3 = 0.001
micro µ = 10^-6 = 0.000 001 (one-millionth)
nano n = 10^-9 = 0.000 000 001 (one-billionth)
pico p = 10^-12 = 0.000 000 000 001 (one-trillionth)

Steve McCrea
http://www.kilomegagiga.com
http://www.roadlovers.com Comfort travel