Here's why:
* Direct Comparison: A triple-beam balance directly compares the unknown mass of the rock to known standard masses (the weights on the beams).
* Indirect Measurement: Indirect measurement involves using a formula or relationship to calculate the unknown quantity. Examples include using a ruler to measure length and then calculating volume using the formula for the shape of the object.
The triple-beam balance doesn't rely on formulas or relationships. It directly compares the rock's weight to the known weights on the beams to determine its mass.
