Measurement and Sci Notation

A quantitative observation is called a measurement and consists of a number and a unit.

Very large or very small numbers are conveniently expressed by using scientific notation.

• The number is expressed as a number between 1 and 10 multi-
  plied by 10 and raised to a power.

Units provide a scale on which to represent the results of a measurement. There are three commonly used unit systems.

• English

• Metric (uses prefixes to change the size of the unit)

• SI (uses prefixes to change the size of the unit)

All measurements have some uncertainty, which is reflected by
the number of significant figures used to express the number.

Rules exist for rounding off to the correct number of significant figures in a calculated result.

We can convert from one system of units to another by a method called dimensional analysis using conversion factors.

Conversion factors are built from an equivalence statement, which shows the relationship between the units in different systems.

Density represents the amount of matter present in a given
volume