The SI System (Units) of Measurement

Key points

The fundamental units of the SI system are: ampere, Kelvin, kilogram, meter, mole, and second (along with candela which is not needed for IB Physics)
- Always convert to these units.
Numbers that are very big or very small can be expressed in powers of 10 (scientific notation)
- Become familiar with the corresponding metric prefixes.

There are seven fundamental units of the SI system, six of which are used for the IB.
- Luminous Intensity is measured in candela (cd) but is not used in the IB curriculum
Whenever working with any relevant quantities, convert all given values to these units.

Small or large quantities can be expressed in terms of units that are related to the basic ones by powers of 10
- This is known as scientific notation
Each power has a prefix associated with it shown to the table on the left.
- mirco, milli, Kilo, etc. are known as metric prefixes.
  - Become familiar with their names, symbols, and corresponding powers.
Expressing a quantity as a plain power of 10 gives what is called the order of magnitude of that quantity
- This can be used to find the ratio between two different quantities

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