Why do you use metric units in science?

Answer 1

There are several advantages. Some of them are:

1. They are internationally agreed as standard. Not like a gallon which can mean one amount in the US and another in the UK.

2. Orders of magnitude for the same measure are related by simple decimal conversions and only a handful of prefices are required (although there are a lot more). By way of contrast, the Imperial system uses:

• 2 pints in a quart
• 3 feet in a yard
• 4 quarts in a gallon
• 6 feet in a fathom
• 8 furlongs in a mile
• 9 square feet in a square yard
• 12 inches in a foot
• 14 pounds in a stone
• 16 ounces in a pound

and so on, and on and on. The decimal structure also makes it very simple to use scientific notation for small and large quantities.

3. It is used by most people in the world. The main recalcitrant countries are USA, Liberia and Myanmar. Even in the US, scientists normally use SI. When they don't they have disasters like the one that trashed NASA's Mars Climate Orbiter!

4. There are many simple relations from measures for one characteristic to another. For example, the SI unit of length is 1 metre. 100 square metres = 1 are, the unit for area. 1 cubic metre = 1000 litres, the unit for volume.