PHY 171 - Chapter I - Version B - Model, Theories and Laws

Scientific laws are descriptive. This means they

Copernicus theorized that earth goes around the sun because "retrograde motion of Mars" could not be explained otherwise

A theory cannot be proven 100 percent.

For less general statements, the term "principle" is used rather than law.

You can be 100 % certain that your physics professor today is the same professor you saw last week but not his clone

Discovery of a new particle requires confidence of at least 99.99994 percent.

Which is high precision and high accuracy ?

No measurement is exact; there is always some uncertainty due to limited accuracy and difficulty reading results.

To be called "law", a statement must be found experimentallty valid over a wide range of phenomena

In social science, confidence of 95 percent may be considered significant. In physical science it is usually higher.

Aristotle believed that sun goes around the earth because his observation and testing supported the idea

Which way might you use to estimate the radius of the earth ?

Which one is better ? A model or a theory.

It should not be assumed that theory is completely "proved" by testing because

One important aspect of science is observation of events which includes design and carrying out experiments.

which is high precision but low accuracy

Which is low precision and high accuracy ?

Which of the following are True ?

The principal aim of all sciences, including physics, is generally to search for order in our observations of the world.

Science requires testing of its ideas to see if their predictions are borne out by experiment.

A model is relatively simple and provides structural similarity to the phenomenon being studied

History of science tells us that long-held theories can be replaced by new ones

A theory is broader, more detailed than model, and gives quantitatively testable predictions, often with great precision