1. Motion Scientists

2. Aristotle Aristotle: Greece- 335-325 B.C. What he said people believed because he was well educated

3. Aristotle Gravity: heavier objects fall faster than light objects Experiment: Dropped rock and feather at the same time, the rock hit the ground first Motion: objects only move if you push/pull them, and objects only stop if you stop pushing/pulling them (*did not mention outside forces) His ideas lasted for about 2000 years = BIG DEAL! That is a LONG time to be considered correct

4. Galileo Italy- early 1600s “Renaissance Man” – good at many things Challenged Aristotle’s ideas

5. Galileo Gravity: objects fall at the same rate regardless of mass Experiment: dropped a 3 pound cannon ball and a 5 pound cannon ball from the same height (Tower of Pisa) at the same time, and both hit the ground at the same time This experiment shows the opposite of Aristotle’s idea

6. Galileo Motion: objects in motion stay moving until an “invisible force” or another object stops them (“invisible forces”  friction!) NOTICE: this concept is like Newton’s 1 st Law Galileo is credited with idea of “inertia” Inertia is the resistance to a change in motion

7. Aristotle & Galileo NOTICE: At this point, neither person has mentioned air resistance!

8. Newton England, late 1600s Was Galileo’s student, so used Galileo’s ideas and added to them Combined Aristotle and Galileo’s ideas

9. Newton Gravity: – Objects fall at the same rate regardless of mass, in the absence of air resistance Motion: 3 Laws 1.Law of inertia (object in motion stays in motion, object at rest stays at rest, until outside force) 2.Force = mass x acceleration **need more force to move a larger mass! 3.For every action, there is an equal and opposite reaction