Used a couple of US recipes recently and most of the ingredients are in cups, or spoons, not by weight. This is a nightmare to convert. Do Americans not own scales or something? What's the reason for measuring everything by volume?
On March 30, 1791, the French Academy of Sciences defined the length of a meter. Before this date, there were two definitions to this measure of length: The first was based on the length of a pendulum and the second was based on a fraction of the length of a half-meridian, or line of longitude. The French Academy chose the meridian definition. This defined one meter as one ten-millionth of the distance from the Equator to the North Pole.
The meter is the basic unit of distance in the International System of Units (SI), the world’s standardized system of measurement. Since the 1960s, all countries have adopted or legally recognized the SI. As a universal standard of measure, the meter helped ease the exchange of commerce and scientific data.
However, the definition of a meter has changed since 1791. In 1983, the meter got its current definition. The meter is defined as the length of the path travelled by light in a vacuumduring a time interval of 1/299,792,458 of a second.
The meter was never to do with metal, and every metric definition is scientifically found, not based off of someone’s foot.
And than what happens when it’s destroyed? You don’t have anything to verify it with, and using a rulered rule to rule will lead to progressively larger deviations from the true original.
This isn't any different from metric systems. If all meter sticks are destroyed, then what do you do? Build everything up again to be able to measure the distance travelled by light in a vacuum in 1/299,792,458 seconds. The procedure would be exactly the same for feet, except you measure the distance travelled in 0.3048/299,792,458 seconds.
A fraction of the Earth's diameter isn't a sound scientific reasoning to define a length. And after that, the definition reverted back to a similar definition of a foot, a fixed length of an item, similar to a foot.
The two main benefits of the metric system are the decimalized behavior of its units and that the scientific community adopted it early, creating additional units from the standard and allowing for greater precision of the initially defined units over time.
However, the value in the meter being its length is the same as everyone agreeing the Prime Meridian goes through Greenwich, UK; it is because everyone agrees to it.