Because it relates to more than one branch of knowledge. It combines more than one academic disiplines.
Answer:
Eventually, these individual laws were combined into a single equation—the ideal gas ... We find that temperature and pressure are linearly related, and if the ... then P and T are directly proportional (again, when volume and moles of gas are ... of the variables, and they are more difficult to use in fitting theoretical equations ...
Explanation:
A physical property is any property that is measurable, whose value describes a state of a physical system. The changes in the physical properties of a system can be used to describe its changes between momentary states. Physical properties are often referred to as observables. They are not modal properties.