The history of the Metric System in 7 minutes

Summary

The video traces the fascinating evolution of measurement systems, from the use of human body parts like the forearm and waist in ancient times to the creation of the metric system during the French Revolution. It details the struggles of early scientists who defined the meter and kilogram, leading to the establishment of a global standard. The story highlights how measurements have been refined over time, culminating in the International System of Units (SI) based on unchanging constants of the universe, which is now widely adopted across the scientific and professional world.

Takeaways

• 😀 Ancient measuring tools were primarily based on human body parts, like the Cubit used by the Egyptians, which was the length of the Pharaoh's forearm.
• 😀 Various early units of measurement were based on arbitrary metrics, such as the yard (man's waist), the pound (Libra), and the mile (Roman soldier's paces).
• 😀 Local variations of measurement systems across Europe, such as 250,000 unique units in France, caused confusion and inconsistency in the use of measurements.
• 😀 The French Revolution played a key role in standardizing measurements, leading to the creation of a new system of measurement in 1790.
• 😀 The meter was defined as 1/10,000,000th of the distance from the North Pole to the Equator, though early measurements were imprecise.
• 😀 Pierre McCain and Jean-Baptiste Stelarm worked for seven years to measure a segment of the Earth's meridian to define the meter accurately.
• 😀 A small error in McCain's calculations led to the meter being slightly shorter than intended, affecting the original polar circumference of the Earth measurement.
• 😀 The kilogram was originally defined by the mass of a cube of water measuring 10 centimeters per side, using a prototype kept in French archives.
• 😀 The metric system was adopted in France by law in 1795 and gradually spread across Europe and the world, particularly through colonial influence.
• 😀 The metric system went through further revisions, eventually being tied to constants of nature, such as the speed of light, to ensure precision and consistency.

Q & A

What were some of the earliest measuring tools used by ancient civilizations?

The earliest measuring tools were essentially human body parts, such as hands, arms, and feet. They were not very precise, but worked well for basic tasks like building houses or fences.

How did the ancient Egyptians standardize measurements for building projects?

The ancient Egyptians used the 'Cubit', a unit based on the length of the Pharaoh's forearm, specifically the royal forearm. They created measuring rods from this standard to ensure consistency in building projects like cities and pyramids.

How were other units of measurement derived across various ancient civilizations?

Other units were often derived from arbitrary sources such as farming or the human body. For example, the yard was based on a man’s waist, the pound was initially defined as 5076 English grains, and the mile was defined as 1000 paces of a Roman soldier.

What was the issue with measurements across different regions in Europe before standardization?

Measurements varied widely from city to city, with different values for the same unit. For example, France had 800 different units of measurement, and each had hundreds of variations, leading to a system of 250,000 unique units.

What prompted the French Revolutionaries to standardize measurements?

During the French Revolution, the goal was to revolutionize society and eliminate arbitrary systems. The revolutionaries sought a universal standard for measurements to replace the inconsistent and confusing regional systems.

What is the origin of the modern meter, and how was it initially defined?

In 1790, French revolutionaries appointed a group of scientists to define a new measurement. The meter was defined as one ten-millionth of the distance from the North Pole to the Equator, though the exact measurement was not fully accurate at the time.

Who were Pierre McCain and Jean-Baptiste Stelmarm, and what role did they play in defining the meter?

Pierre McCain and Jean-Baptiste Stelmarm were tasked with measuring a section of France to calculate the meter. Their work involved triangulation using repeating circles to determine the distance accurately.

Why did the initial definition of the meter end up being slightly inaccurate?

McCain made a small error related to the latitude of a city, which caused the calculated meter to be 0.02 shorter than it should have been. Despite this, the slightly inaccurate meter was adopted for further measurements.

What led to the creation of the International Bureau of Weights and Measures in 1975?

As more countries adopted the meter, discrepancies arose due to wear and tear on physical meter bars. To resolve this, the International Bureau of Weights and Measures was established to create a global standard for measurement.

How did the redefinition of units in 1960 impact the metric system?

In 1960, the International System of Units (SI) was introduced, redefining units based on constants like the speed of light and cesium radiation frequency. This eliminated reliance on physical standards like the meter bar, offering greater consistency.