What is the need for SI system of units?

You may already know that different parts of the world had a different system of units in the past. That is the CGS, FPS, and MKS system. But then the SI system of units was made standard in the world. We want you to think why that happened.

SI system of units

The seven base units from SI, from Wikipedia

Present situation

We were not entirely correct when we used “in the past” in the first sentence of this post. Even now different countries of the world use different system of units. The most famous country is the USA. They use the FPS system and if you come across any American TV shows, then you will hear the words pounds, feet, inches, ounces, etc. thrown around. That is because they use those units in their day to day life. But we, in India, use meter, centimeter, grams and kilograms.

Why SI then?

If this is the current state, then why is the SI system made standard in our world?

Think of this: In the past, the world was not as inter-connected as it is now. Different countries had their own independent scientists working on research. And based on where the scientists were, they used those system and came up upon different theories and experiments that were correct! Different units does make the underlying theory or experiment invalid. The problem arose when these scientists would publish papers based on their results.

A scientist from USA may publish his paper using the FPS system and it would be fine and completely understood in the USA. But once other scientists all over the world want to read that published paper, then they will have the difficulty of conversion of units. Instead of focusing on the work and new theory, the scientists would be perpetually stuck making simple calculations converting units. Similarly, if an Indian scientist publish a paper with her own theory using the MKS system, then her theory will be easily read in all the countries where MKS system is used. But once the American come across the paper, then they will have the same difficulty reading the paper by Indian scientist.

For this reason, it is recommended to use the International System of Units (SI) when you are dealing with anything academic or scientific. Though people in their day to day life continue to use whatever they have been using from the past and it will be a slow process to get everyone in the world to use one system of units.


The initiative to make a standard system of units began in 1948 but was accepted in 1960! The main problem was the CGS system.

Read more by clicking here.

Now that you know the need for one standard system of units, what do you think should be the case? Is it better to have one standard system or multiple systems depending on countries?

Stay curious.

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1 Response

  1. December 17, 2016

    […] And so, in 1983 the new definition of one metre was adopted. the 299,792,458 is the speed of light in vacuum in one second. This precise definition gives even better global standard with which every scientist can study. Now, different people in different areas do not have to find some stick with which to measure things to study. We have discussed this issue with measurement in our blog post here. […]

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