Physical Science

Physical science is a broad subject. We cannot cover it all. Besides, science is boring. So, we use natural phenomena and man-made devices as tools to discuss some topics in physical science.

(1)  Is the earth stationary or moving (e.g., rotating and/or orbiting)?  There are two theories and people coined two names for them: "geocentrism" and "heliocentrism." How do we know which theory is right? You can click on the following link to learn more about why people believe in these theories:  Geocentrism and Heliocentrism.

(2)

(to be continued)