The Metric System describes units of measurement including Celsius for temperature, grams for mass, and liters for volume. It also outlines metric prefixes like kilo for 1000 and milli for 0.001 that are used to modify metric units of distance, mass and volume. While weight depends on gravity, mass is a measure that does not change and is quantified using grams. A mnemonic is provided to help recall the metric prefixes used to convert between metric units of measurement.