This criterion of gear selection is used in countries which have adopted the metric system and is intended to standardize gear selection. To define a gear's module, the pitch diameter (the teeth ...

In the meantime, a new system of weights and measures, developed by French scientists following the Revolution of 1789, gained increasing international use. This metric system had as its fundamental ...

NARRATOR: The metric system is a way of measuring things. So with length, the metric measurements are millimetres, centimetres, metres and kilometres. A stamp, would be measured in millimetres.

Here’s a good trivia question: What are the only 3 countries in the world that do not use the metric system? Everybody knows the good ol’ hard headed USA is in there, but the other two? How about ...

No such simple relations existed in standard units of weight and measure among units of length (inches, feet, yards, miles) or among units of length, volume and weight. In other words, the French ...