As discussed, the metric unit of mass was originally related to length, with a liter (1000 cm3) of water having a mass of 1 kg. The standard metric unit of volume is the cubic meter (m3) and this volume of water was used to define a larger unit of mass called the metric ton (or tonne, as it is sometimes spelled). A metric ton is equivalent to how many kilograms?

THINKING IT THROUGH. A cubic meter is a relatively large volume and holds a large amount of water (more than a cubic yard; why?).
The key is to find how many cubic volumes measuring 10 cm on a side (liters) are in a cubic meter. A large number would be expected.