Lesson 2: Converting Between SI Units - The SI System Units

   Constructing Knowledge

Earlier in this Unit, you were introduced to linear measurement units used in the SI system. The SI system also includes units for mass (kilograms), and capacity (litres), among others. Prefixes are used to represent different sized units. The prefixes are related by powers of 10. For example, kilometres and centimetres are both derived from the base unit metre. A kilometre is 1000 (103) times longer than a metre, and a centimetre is 100 (102) times shorter than a metre.

The table below shows some commonly used prefixes and how they are related to the base units. The conversion factor shows how many of that unit make up the base unit. For example, there are 0.001 kilometres in a metre.

SI Prefix Table
Prefix Conversion Factor Length Volume Mass
kilo 0.001 kilometre (km) kilolitre (kL) kilogram (kg)
hecto 0.01 hectometre (hm) hectolitre (hL) hectogram (hg)
deca 0.1 decametre (dam) decalitre (daL) decagram (dag)
Base Unit 1 metre (m) litre (L) gram (g)
deci 10 decimetre (dm) decilitre (dL) decigram (dg)
centi 100 centimetre (cm) centilitre (cL) centigram (cg)
milli 1 000 millimetre (mm) millilitre (mL) milligram (mg)



2014 © Alberta Distance Learning Centre