When the pans contain exactly the same mass the beam is in balance. ... You can place an object in one pan and standard weights in the other to find what the object weighs. Here balance scales are used to show that the box "x" has a mass of 4
a balances measure mass, while scales measure weight. So if you bring a balance and a scale to the moon, the balance will accurately give you the mass of, say, a moon rock, whereas the scale will be affected by the gravity. A balance determines mass by balancing an unknown mass against a known mass.
