Physics Lournal

1.1 The Nature of Physics

Physics can be considered an experimental science: Physicists make observations of natural phenomena, and try to find patterns that relate to these phenomena, and these patterns are referred to as physical theories, and when they are very well established, they are called physical laws or physical principles.

The Meaning of Theory: A theory is more than a random thought, or hypothesis, rather, a theory is an explanation of some phenomena based on observations and fundamental principles.

To develop a physical theory, physicists must learn how to ask the necessary questions, and design experiments which will provide data, from which appropriate conclusions can be drawn, which represent the answer(s) to the original questions.

Legend has it that Galileo Galilei dropped light and heavy objects off of the Leaning Tower of Pisa to see if the rate at which they fell was different From examining the results of this experiment, he inductively concluded that the rates of acceleration of falling objects was independent of their weight.

The development of such physical theories as Galileo's is no straightforward process, and often takes the wrong directions, and unnecessary pit stops, and the discarding of less accurate theories in exchange for more robust ones: physics is not just a collection of facts and principles, it is the process by which general principles that describe natural phenomena are generated.

Also, no such theory is treated as the final truth, as there is always a possibility that new observations will require the revision of theory, or replacement entirely: we can disprove a theory with contradictory observations, but we can never prove that a theory will account for every possible observation.

Consider Galileo's theory with a bit more specification, such as dropping a feather and a cannonball, which certainly do not fall at the same rates.

This is not an indication that Galileo's discoveries were incorrect, but rather that the theory he used to explain them were incomplete: His theory is correct in a vacuum, which eliminates the effects of air resistance on falling objects.

What this means is that Galileo's theory has a range of validity: it applies only to objects for which the force of air resistance is less than the weight.

Referenced in

Units, Physical Quantities & Vectors

1.1 The Nature of Physics

1.3 Standards and Units

As stated in section 1.1, Physics is an experimental science. Experiments require measurement of some sort, and we usually use numbers to describe the output of a measurement.

1.1 The Nature of Physics