If I asked you to show me how long a inch is, what would you do? How about a yard? I first learned the measurement of a yard from my mom, measuring out rope for a game of tug-of-war. It is the approximate distance from your finger tips to the center of your body and that was how I have measured out approximate lengths since. This is how the majority of measurements came about in our English system today, by standardizing the approximate measurements previously used to enable fair trading (usually by accepting the length of the reigning monarch's foot).
But I want to talk about the Ancient Hebrew system of measuring length instead. In this time, the measurements started out as approximations of the length of certain body parts, and again were standardized to be used by the entire nation. Distances longer than an "reed" (approx. 9 feet) were measured by the number of paces or the days that it took to journey there. Distances did not become standard until the Greek and Roman influence of later centuries. The measurements that were used were rarely taught, just accepted as commonplace and that everyone understood what was meant by them. I mean, really, how could you tell a fishing story without indicating the length of your fish and exclaiming that it is 4 feet long! Idiocy
A cubit is the

basic unit of measurement in the Hebrew system, and is the approximate length from fingertips to elbow. In the culture there became two standardized measurements, the common cubit and the long cubit which measured 17.5 inches and 21.5 inches respectively. A handsbreadth was another, measuring the length of the palm across the base of the fingers (approx. 4 inches). In Ezekiel's time (600 BC) the measurements of the future temple were given mainly in "reeds" which was a length of wood cut to the length of six long cubits, or approximately 9 feet.
For me personally, I enjoy the logically metric system. I guess I really am a science nerd. :-)