Introduction to Physics (PHSX 1010)
Adam Johnston

Course notes:
ARISTOTELIAN PHYSICS

Today's discussion focuses on the natural laws described by Aristotle (384-322 BC).  Often we call this "Aristotelian Physics"; although, it wasn't really "physics" in the same way that we think of physics today.  Aristotle was a philosopher, and was trying to figure out a simple set of rules that the universe abided by.

Basically, Aristotle's physics relied on the idea that different materials had different resting places, and that all materials naturally wanted to be at rest.  The four materials that we can interact with, according to Aristotle, were earth, water, air, and fire.  Things made of earth tended to fall, while items which are hot, such as steam, were said to be made from fire and would rise.  Water items would sit above earth materials, and air would rest above water but below fire.  Thus, the motion of any item could be predicted based upon what it was made from.  Many examples of this are demonstrated in class.

There are some modifications that were made to this idea in order to get a few other details pinned down.  Yet, there were still some problems.  Even though Aristotle's system is quite simple, understandable, and even works in many cases, it does not stand up to experiments and testing.  In his defense, Aristotle was not a scientist, but a philosopher, so he wasn't concerned about such nonsense.  However, when Galileo came along (in the late 1500's and early 1600's A.D.), he would actually put many of Aristotle's ideas to test via experiments.  This gave Galileo the lofty title of "the father of science."  By putting this on his resumé (just kidding), he was able to get a nice academic position in Padua, Italy; though such a title didn't save him from the Inquisition a few years later.

Galileo and his (and our) experiments with motion are topics for next lecture.