# Physics Skills Mini-Lessons: Metric Prefixes

The Metric System (SI) is the measurement system used in science and technology around the world. Though the US juggles both the US Customary System and the Metric System, we will focus on the Metric System only in future Finding Physics lessons. In order to use the Metric System, you need to be familiar with the prefixes that can be connected to the base unit for measurement.

The first mini-lesson introduces the concept of prefixes and why they exist at all. It reviews common base units, both fundamental and derived, that are used with these prefixes. The need for prefixes arises when it is required to measure things that are incredibly large or small compared to the base unit. Though memorization of all prefixes is typically not required in an introductory physics class, knowing how to read a prefix chart is required. This lesson shows how to create a conversion factor from a standard prefix chart.

The second mini-lesson takes the conversion factor that was created from the prefix chart and uses it in dimensional analysis. Dimensional analysis is when you convert from one unit to another by multiplying the original quantity by a factor of 1. What is this factor of 1? It is the conversion factor that was created from the prefix chart.

Dimensional analysis is often used to convert from a base unit to a prefix or from a prefix to a base unit. When using equations in physics, all quantities must be in their base unit, except mass which must be in its fundamental unit of kilogram. See examples of dimensional analysis in this video to familiarize yourself with conversions using metric prefixes.

Want more practice with metric prefixes? Then sign up for the __Physics Skills Summer Series__ or other workshops including this content. Want one-on-one attention? Then sign up for a __tutoring session__ that focuses on metric prefixes.

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