Chapter 3 Quiz: Olivia Ward

1. How did Copernicus, Tycho, and Kepler challenge the Earth centered model?

Copernicus proposed the Sun-centered model and used the model to determine the layout of the solar system. The model used circular orbits. Tycho compiled the most accurate measurements of the planet positions but still thought the Earth was the center of the solar system but recognized that the other planets go around the Sun. Kepler discovered that planets do not have circular orbits, and instead of ellipse shaped orbits.

2. What are Kepler's three laws of planetary motion?

The first law is that the orbit of each planet around the Sun is an ellipse instead of the originally thought of circular orbit. The Sun is a focus of the ellipse. The second law is as a planet moves around its orbit, it sweeps out equal areas in equal times. A planet travels faster when it's closer to the Sun and slower when it's farther away.

3. How did Galileo solidify the Copernican revolution?

Galileo overcame three major issues of the Copernican view. His experiments proved that objects in air would stay moving with Earth and that they will stay in motion until a force acts to slow them down. He saw spots on the Sun as well as mountains and valleys on the Moon, which disproved the idea of heavenly perfection. It was also proven that the stars were further than originally thought and that not all objects orbit Earth.

4. How can we distinguish science from non-science?

 Not all knowledge comes from science. Science is based on the proposition and testing of a hypothesis which observes natural causes. Scientific experiments can only progress from the creation and testing of models. The hypothesis cannot be based on the supernatural.

5. What is scientific theory?

A scientific theory must explain a wide variety of observations, be supported by a largely compelling body of evidence, and not fail any tests of validity.

6. What does the universe look like from Earth?

 From Earth, we can see half of the celestial sphere which allows us to see different parts of the universe. The universe has over 2,000 stars and 88 constellations which can be seen at different times of the year.

7. Why was planetary motion so hard to explain?

Planetary motion was so hard to explain because of retrograde, which means the planets are moving backwards. Planets typically move eastward but occasionally move westward.

8. Why did the ancient Greeks reject the real explanation of planetary motion?
   
   The ancient Greeks rejected the real explanation of planetary motion because they believed that the Earth was the center of the universe and that the heavens were perfect, which only allowed objects to travel in perfect circles.
   
   
9. In what ways do all humans use scientific thinking?

All humans use scientific thinking in their day to day observations and do simple trial-and-error experiments to develop upon these observations. Scientific observations unintentionally begin at a young age, especially for children observing the force of gravity.

10. How did astronomical observations benefit ancient societies?
    
    Ancient societies were able to keep track of time throughout the day as well as the seasons which allowed for agricultural practices and religious events that accompanied a particular season to take place. Navigation was also highly based on the stars.