A triple beam balance accurately measures mass; however, often a scale that measures weight is used, and the mass is inferred. Mass is the measurement of the amount of matter present in an object. Weight is the measurement of how the mass is affected by the present gravitational force.
A triple beam balance measures mass because the balance compares an object to an object with a known mass. The gravitational force present does not alter the measurement because both the object and reference object are affected by the force equally. Digital scales are typically used in research because of their precision, even though the property measured is actually weight.