A physical quantity is the property of an object that can be quantified. For instance, the physical quantities are the length of a rod or the mass of a body. Measurement is the act of comparing a physical quantity with its unit. The measurement result is the value of a physical quantity obtained employing measurement. The present SI has seven base quantities: time, length, mass, electric current, thermodynamic temperature, amount of substance, and luminous intensity. A physical quantity is a property of a material or system that can be quantified by measurement. A physical quantity can be expressed as the combination of a numerical value and a unit. Types of data measurement scales: nominal, ordinal, interval, and ratio.