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=== Physics in Antiquity ===

=== Physics in Antiquity ===

Ancient [[Greek]] scholars, such as [[Democritus]] and [[Aristotle]], thought of the material [[universe]] as being composed four different [[elements]]--[[earth]], [[air]], [[fire]], and [[water]].  Motion and interactions between objects were explained by the concept of a "natural state" for each element.  Bodies tended to move towards their natural state, and remained motionless when they attained it.  For example, a rock fell to the ground after being tossed in the air because it was composed mostly of earth; as such, it moved toward its natural state at the center of the Earth as much as it was able.  Democritus proposed that matter was made of indivisible atoms. The Greeks also made advances in [[astronomy]]; Aristotle showed that the Earth was round;  [[Ptolemy]] developed a [[Geocentric theory|geocentric]] (Earth-centered) model of the solar system; and Aristarchus developed a [[heliocentric]] (Sun-centered) model.

[[Ancient Greece|Ancient Greek]] scholars, such as [[Democritus]] and [[Aristotle]], thought of the material [[universe]] as being composed four different [[elements]]--[[earth]], [[air]], [[fire]], and [[water]].  Motion and interactions between objects were explained by the concept of a "natural state" for each element.  Bodies tended to move towards their natural state, and remained motionless when they attained it.  For example, a rock fell to the ground after being tossed in the air because it was composed mostly of earth; as such, it moved toward its natural state at the center of the Earth as much as it was able.  Democritus proposed that matter was made of indivisible atoms. The Greeks also made advances in [[astronomy]]; Aristotle showed that the Earth was round;  [[Ptolemy]] developed a [[Geocentric theory|geocentric]] (Earth-centered) model of the solar system; and Aristarchus developed a [[heliocentric]] (Sun-centered) model.

=== Medieval Advances ===

=== Medieval Advances ===