What does unit conversion involve?

Unit conversion specifically refers to the process of changing from one measurement to another within the same physical quality, such as converting inches to centimeters or pounds to kilograms. This process is vital in many fields, including instrumentation, as it ensures accurate communication of measurements that can vary in their unit representation. Understanding how to convert between different units of the same quantity enables practitioners to interpret data correctly and perform calculations using consistent units.

The other options describe different processes that are not limited to unit conversion. Changing from one physical quality to another implies a transformation between different types of measurements (e.g., temperature to pressure), which is beyond the scope of unit conversion. Changing units based on weight is a more specific case of unit conversion but does not encompass all unit conversions. Changing scale sizes might relate to resizing or altering the representation of data but also does not specifically address unit conversion in the context of changing measurements.