how does the metric system work?
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What part of the metric system is it you need explained?
The metric system or the “International System of Units” as it is formally known is a System of units used throughout the world. (The units are also know as **SI-Units** because French abbreviations tend to be backwards compared to English ones.)
It replaced older systems used in Europe where every country and sometimes every large city had their own system of weights and measures. It used to that there were dozen of different types of pounds and feet and everyone’s miles and tons had different amounts of their pounds and feet.
Some of that confusion lives on with for example Gold being measured in different ounces and pounds than other stuff. regular US pounds have 16 regular US ounces but gold is measured in troy pound and troy ounces where there are 12 troy ounce to the troy pound.
Also American tons are different from British imperial tons despite the pounds being the same.
The confusion was quite a lot worse in ages past when every city had their own units, everyone measured things differently and nothing matched up.
During the age of enlightenment and with the background of the french revolution new units were created that should get rid of the confusion of all the old ones.
One important thing is that instead of of going with larger and smaller unit totally disconnected from each other, for every thing that was measured some base unit was created and larger and smaller units were created by adding the same prefixes. all those prefixes were powers of 10 and mostly powers of 1000.
So you did no longer have to memorize how many foot there were in a mile or how many pounds in a hundredweight.
All you needed to know was that kilo- meant thousand and you instantly knew that a kilometer was 1000 meter and a kilogram was 1000 gram and a kilojoule was 1000 joule etc.
This also made conversion between units easier as you did not have to do any actual math.
How many kilometer are 1609 meter?
1.609 km
No math necessary you just need to move the decimal point left or right a bit.
(Time and angles are the exception. There was an attempt to decimalize time and decimal angle measures exist, but we still use a 24 hour day today with each hour having 60 minutes and 60 seconds. Milliseconds however are a thing. similarly circles are divided into 360 degrees and each degree into 60 minutes and each minute of an arc into 60 seconds. tradition won out there)
The other advantage was that you get from one unit to the other by multiplying or dividing by full units.
Power for example is mass times area divided by time cubed.
If you were asked how many pound square inches per cubic fortnight you would need to get a single horsepower, not even people who use those units would be able to easily tell you of the top of their head.
In SI units 1 Watt is simply 1 Kg times a square meter divided by a second cubed.
All commonly used electrical unit like Volt and Ohm etc are actually metric units this way.
Doing any sort of physics math without SI units get unnecessarily complicated very fast.
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