An introduction to physical quantities and units of measure. This video explains the need for units in physics and gives an example of what can happen when scientists use the wrong units. Additionally the International System of Units is introduced as well as some SI Prefixes.
A common mistake of a beginning physics student is the confusion of physical quantities and units of measure. Physical quantities are any of the characteristics of objects in nature that can be measured. Units of measure are the basic standards of measurement used to measure a physical quantity. Different physical quantities are measured with different units of measure. For example, you wouldn’t measure your weight using seconds!