Why's a Meter a Meter?

The video explains the evolution of the meter as a unit of length. Initially, various units like the cubit and yard were used. The French Academy of Sciences aimed to standardize measurements, leading to the meter being defined as a fraction of Earth's circumference. A platinum bar was created as a standard, but it had limitations. In 1960, the meter was redefined using krypton-86 light wavelengths. Finally, in 1983, it was redefined as the distance light travels in a vacuum in 1/299,792,458 of a second, based on the constant speed of light.

What was one of the initial ideas for defining the meter that was ultimately not adopted?

• The length of a pendulum that swings in one second

• The distance from the equator to the South Pole

• The length of a human forearm

• The height of the Eiffel Tower

Why was platinum chosen for the original meter bar?

• It does not rust easily

• It is the hardest metal available

• It is cheaper than other metals

• It is the most abundant metal

What was the main reason for redefining the meter using light wavelengths?

• Light is more colorful

• Light is cheaper to produce

• Light is a universal constant

• Light is easier to measure than metal bars

Which element's light wavelength was used in the 1960 definition of the meter?

• Krypton-86

• Helium

• Neon

• Argon

How is the meter currently defined?

• As the wavelength of helium light

• As the length of a platinum-iridium bar

• As the distance light travels in a vacuum in a specific fraction of a second

• As the distance from the equator to the North Pole