1. The name of the CalTech professor who begins the video is Dr. Mike Brown.
2. What famous scientist developed the Law of Gravity that the video is about? Isaac Newton.
3. The law of gravity helps explain the orbits of planets, stars, and galaxies. It also helps explain why objects fall to the earth.
4. What might have happened to Newton if he had not returned to his family’s farm? He might not have had the time or inspiration to develop his theories on gravity and motion.
5. What event did this remind him of? An apple falling from a tree.
6. How was the Earth’s gravity interacting? It was pulling the apple downward toward the center of the Earth.
7. The principle of the pendulum was used to measure time.
8. How old was Newton? 23 years old.
9. Who named the words that grew into the scientific revolution? Sir Isaac Newton.
10. Where were these ideas from? From his observations and experiments during his time at his family’s farm.
11. What was similar about the Ptolemaic and Copernican systems? Both attempted to explain the motion of celestial bodies, though they differed in their models (geocentric vs. heliocentric).
12. When is this seen in the Copernican system? When planets appear to move backward (retrograde motion) due to relative positions and motions of Earth and other planets.
13. What were Galileo’s findings on inertia? He found that an object in motion tends to stay in motion unless acted upon by an external force.
14. Galileo’s laws explained motion on the Earth. Where have been explored earlier above and beyond the Earth? In space, particularly with planetary motion.
15. What were his three laws?
- First Law (Law of Inertia): An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
- Second Law: The acceleration of an object depends on the mass of the object and the amount of force applied (F = ma).
- Third Law: For every action, there is an equal and opposite reaction.
16. What is the equation for Newton’s Law of Gravity? F = G * (m1 * m2) / r²
17. What is the acceleration of gravity equal to? Approximately 9.8 m/s² on Earth’s surface.
18. Why does the acceleration of the apple toward the Earth depend on the mass of the apple? It doesn’t — the acceleration due to gravity is independent of the mass of the falling object (in the absence of air resistance), as shown by Galileo and confirmed by Newton.
19. How does the acceleration of gravity on the Moon compare to the acceleration of gravity on the Earth? The acceleration of gravity on the Moon is about 1/6th that of Earth’s, or approximately 1.63 m/s².
Parent Tip: Review the logic above to help your child master the concept of mechanical universe worksheet.
