1. 1.3 Measurement Scientists work with very large or very small numbers
Scientific notation uses a shortcut to avoid writing out all the zeros
Scientific notation is a way of expressing a value as a product of a number between 1 and 10 and a power of 10
e.g. 3 x 108

2. International System of Units (SI)
There are 7 metric units known as base units:
meter (m) – length
kilogram (kg) – mass
kelvin (K) – temperature
second (s) – time
mole (mol) – amount of a substance
ampere (A) – electric current
candela (cd) – luminous intensity

3. Derived Units Derived units are made from combinations of base units.
Density is a derived unit
e.g. Density = mass ÷ volume

4. Writing Quantities Quantities are seldom convenient to write out
A more compact way is to use a metric prefix
A prefix indicates how many times a unit should be multiplied or divided by 10

5. Precision Precision is an assessment of how exact a measurement is.
Significant figures are all the digits that are known in a measurement, plus the last digit that is estimated.
The fewer the significant figures, the less precise the measurement is.
A calculated answer is limited by the least precise measurement used in the calculation
Accuracy is the closeness of a measurement to the actual value of what is being assessed.