What does a triple beam balance measure
Formal Laboratory: Measuring mass in orbit.
To use an inertial balance to measure mass. First, you will "calibrate" the balance using known masses, then use the balance to find the mass of "unknown" objects.
"Mass: The quantity of matter in a body. More specifically, it is a measure of the inertia or "laziness" that a body exhibits in response to any effort made to start it, stop it, or change in any way its state of motion."
(Hewitt, Paul, Conceptual Physics, Second Edition, 1992, p. 32)
Scientists measure things. A scientific question to ask is "This definition of mass is very nice, but what does it say about measuring mass?" There are several ways to measure mass - a triple-beam (or electronic) balance measures mass, for instance. The triple-beam balance has a couple of disadvantages, however. First, it is difficult to see how the measurement you make on a balance correlates to the definition of mass given above, and the triple-beam balance won't work where there is no gravity. In this lab we will measure mass by utalizing its true nature, that of resisting any change
in its state of motion.
If mass measures the "laziness" of an object in response to efforts made to change its velocity, it makes sense that you should be able to measure mass by making an effort to change the velocity of an object and recording its "laziness". This is what an inertial balance does. Two strips of spring steel apply a constant amount of "effort" in order to vibrate a pan back and forth. (A vibration involves speeding up, slowing down, and changing direction (all 3 ways to accelerate), so the state of motion of the object is certainly changed.) If the object can be vibrated back and forth easily, it is not "lazy" - in other words, it does not have much mass. Objects that vibrate slowly have a large mass.
By measuring how fast known masses vibrate on the inertial balance, you can construct a graph that "calibrates" the balance - that is, if you know how quickly an unknown mass vibrates you can use the graph to determine its mass.
You will want to measure one period of oscillation, back and forth.Source: shsphysics.org