What is metric

"My height is 180 cm, and my weight is 70 kg."
"Now it is 15°C here, and the maximum is 25°C."

Words like these said by everyone all contain such units: m, kg, °C, etc. As we all know, these units belong to SI, which is the modern form of the metric system. But do you know what metric system is? And how the metric system was created and developed?

The metric system is an internationally agreed decimal system of measurement that was originally based on the mètre des Archives and the kilogramme des Archives introduced by the French First Republic in 1799. Now it's used everywhere in the world.

The metric system was first developed during the French Revolution to replace the various measures used at that time. On the eve of the French Revolution, France had an estimated quarter of a million different units of measurement. In many cases the value of a unit differed from town to town and even from trade to trade even though they might have the same name. While certain standards, such as the pied du roi (the King's foot) had a degree of pre-eminence and were used by savants (scientists), many traders used their own measuring devices. This gave scope for fraud and hindered commerce and industry.  So People needed to take measures to replace this confusion with a radical new system with fixed values.

The first practical implementation of the new system was the system implemented by French Revolutionaries towards the end of the 18th century. Its key features were that:

• It was decimal in nature.
• It derived its unit sizes from nature.
• Units that have different dimensions are related to each other in a rational manner.
• Prefixes are used to denote multiples and sub-multiples of its units.

These features had already been explored and expounded by various scholars and academics in the two centuries prior to the new system being implemented.

Between 1795 and 1800, during the French Revolution, and with the backing of Louis XVI, the system of weights and measures was totally reformed. The new system of measures had a rational mathematical basis and was part of the radical effort to sweep away old traditions and conventions and replace them with something new and better.  The French philosopher, the Marquis de Condorcet, who was one of those entrusted by Louis XVI to overhaul the system of measurement, characterized the new system as "for all people for all time".

The key units of the republican measures system were:

• The mètre - the unit of length, defined as one ten-millionth of the distance between the North Pole and the equator on the meridian passing through Paris.
• The are - for land area, defined as the area of a square with sides of length 10 metres
• The stère - for volume (particularly of stacked  firewood), defined as 1 cubic metre
• The litre - for dry and liquid volume, defined as the volume of a cube with sides of one-tenth of a metre
• The gramme - for weight, defined as the weight of a cube of pure water with sides of one-hundredth of a metre and at the temperature of melting ice.

From the beginning, French people were not used to the new decimal system. Until 1840 France reinstated the decimal system and called it "metric system".

The metric system developed as the understanding of science and in measuring techniques has advanced. In 1875 the Convention of the metre was signed and control of the metric system passed from France to a trio of inter-government organizations headed by the CGPM and based in Sèvres, France. In 1960, at the 11th conference of the CGPM, the metric system was overhauled and the resultant system named "The International System of Units (SI)". The driving force behind the metric system was the need for a single, rational and universal system of weights and measures that could be used world-wide.

Here are some SI units in our everyday life:

Length: m

Mass: kg

Time: s

Temperature: °C

Potential difference: V

Energy: J

Power: W

Pressure: Pa

In this blog, we talked about what metric system is, and how the metric system was created and developed. In the next blog we will talk about SI (International System of Units).

Preface - Why Metricize

As is known to all, measurement plays an important role in the entire human history. No one can live without measurement. From the very beginning, people knew whether the object is long or short, large or small, heavy or light, hot or cold, etc. by comparing and feeling. But sometimes comparing and feeling were unreliable, so people used their body parts (finger, hand, foot, etc.) or other objects as the standard, and then used it to compare with other subjects. This was the origin of the units of measurement.

With the development of human society, Units of measurement were developing as well, which made people measuring more accurately. However, Units of measurement varied from country to country. For instance, People in East Asia were using the traditional system (Chinese in origin), and people in the UK or its colony were using imperial system. The disunity of units brought inconvenience to international communication, so people wanted to create a new system of units which can be used all over the world.

The first practical realization of the united system of units came in 1799, during the French Revolution, when the existing system of measure, which had fallen into disrepute, was temporarily replaced by a decimal system based on the kilogramme and the metre. In 1837 the decimal system was adopted by France, and also during the first half of the 19th century was adopted by the scientific community. 

In 1875 seventeen countries signed the Conventions of the metre, and the new system is officially called metric system. The signing of the Conventions of the metre is the symbol for the start of the unity of units. With more and more country added the Conventions of the metre, in 1960 the CGPM launched the International System of Units (SI), which means the metric system is used worldwide. The unity of units made it convenient for international communication.

However, there are still some people who are not aware of the meaning of the unity of units. They still stick to a different system of units (e.g. imperial system) in international communication, especially on the Internet, which made people from different countries/regions confused. These people only think about themselves, without considering others. Not only does these people bring inconvenience to others, but also what they are doing is equal to turning the clock back, which is useless. Internet belongs to everyone in the world, not belongs to a specific country/region. People should follow the international practice on it. So I am using the blog to let them get metricized. Getting metricized is very easy. It does not take too much; all you need is trying to go metric in your life, studying and work, etc.

Now let us follow my posts and try to get metricized in your life!

(Note: comments need metricizing as well!)