Understanding the Evolution of the 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 standardized the meter in the 18th century, initially defining it as a fraction of Earth's circumference. A platinum bar was created as the Meter of the Archives, but issues with temperature and material stability led to further refinements. In 1960, the meter was redefined using the wavelength of light from krypton-86. 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 is the meter primarily used as in the International System of Units?

• A unit of temperature

• A unit of mass

• A unit of length

• A unit of time

Which method was initially considered but rejected for defining the meter due to variations in gravity?

• Using the length of a forearm

• Using the length of a pendulum

• Using the length of a foot

• Using the length of a yard

What material was the Meter of the Archives made from?

• Platinum

• Silver

• Gold

• Iron

What was the purpose of the Treaty of the Meter signed in 1875?

• To create a universal currency

• To establish a new unit of time

• To standardize the meter internationally

• To define the kilogram

What metals were used to make the International Prototype Meter?

• Copper and tin

• Platinum and iridium

• Aluminum and steel

• Gold and silver

Why was light considered a better basis for defining the meter?

• It is more colorful

• It is more fundamental and universal

• It is easier to measure

• It is cheaper to use

Which element's light emission was used in the 1960 redefinition of the meter?

• Helium

• Neon

• Krypton

• Argon

What is the current definition of the meter based on?

• The length of a pendulum

• The distance from the Equator to the North Pole

• The speed of light in a vacuum

• The wavelength of krypton-86

How is the speed of light in a vacuum described in terms of its constancy?

• It is a constant, regardless of reference frame

• It varies with temperature

• It depends on the medium

• It changes with pressure

What is the significance of the 1983 redefinition of the meter?

• It linked the meter to a fundamental universal constant

• It made the meter longer

• It made the meter shorter

• It was based on a new metal alloy