To help clear up any confusion when I talk about the “efficiency” or “efficiency score” of the bridges I build. This is a mathematical equation to determine how well a bridge performed.
Simply take the mass that the bridge held, and divide that by the mass of the bridge.
________ = Efficiency
Mass of bridge
Some confusion comes up when I weigh the bridge in grams while add weight to the bridge in pounds. These units do not have the same base, and cannot be divided against each other. I usually convert pounds to kilograms (1kg = 2.2 pounds) and then multiply the number of kilograms by 1000 to get grams.
So if my bridge held 54 pounds, I would convert that to kilograms. 54 pounds equals 24.54 kilograms. That equals 24540 grams.
To get the efficiency, I take 24540 and divide that by the mass of the bridge, which was, say, 33 grams. The efficiency score is then 744.