Physical amounts in science are described in units of the metric or international units system (SI).
Some of the key units include volume liter (L), length meter (m), gram (g), weight kilogram (kg), temperature degree Celsius (°C) and Kelvin (K), and time second units.
A prefix located before a metric or SI device changes the unit's size by 10.
The relationship between two units, measuring identical volume, length, weight, or time, shows equal equality.
Conversion factors are helpful if a quantity in one unit is changed to a quantity in another one.