Unit 2 : Activity 2 : Ptolemaic Model : Copernican Model : Brahe : Kepler : Galileo : Newton : Unit Exam

Unit 2: End of Unit Exam

This assignment consists of four parts. The first is a review with a couple of practice questions linked directly to their answers. The second is a short quiz that you take using Blackboard. It will be instantly scored for you by Blackboard; you only get one chance to take it, however, so be sure you are ready! The third part is an essay question. The question appears below; when you are ready to answer it, log on to Blackboard and submit your essay. Finally, for each unit, you should log on to Blackboard and contribute a question, an answer, or a comment to one of the posted topics. If you would like to introduce a new topic instead of contributing to an existing thread, please send your topic idea to your instructor. If you find the material in this unit challenging, you might want to start with the "discussion" part of the assignment in order to get some help with some of the ideas.

To use Blackboard you will need to be signed up as a student in the course. That means that first you must enroll for credit and then you can login to Blackboard. The instructor will verify that you are enrolled in the course and verify your enrollment in NorthStar.

Brief summary of Unit Two:

This unit covers about 2000 years of the history of astronomical theories about the geometry and dynamics of the Solar System. Topics we have covered include the Aristotelian/Ptolemaic model, the Copernican model, Brahe's model and observations, Kepler's Laws of Planetary motion, Galileo's observations, and Newton's Laws.

Before you go to the quiz, see how you do on these two questions. If you have trouble, you might want to review the unit, send a question to the discussion group, or seek help from the instructor.

Practice Question One

Ptolemy was motivated to produce his model of the Solar System by carefully considering the forces between the Earth, Sun, Moon, and the planets. True or False? Explain.

Practice Question Two

Consider two hypothetical planetary systems, each with only two planets. They are identical except the following. For one system the two planets orbit in perfect circles. For the other, the average sizes of the orbits are the same, but they are more elliptical in shape? How do the periods compare? Are the more elliptical orbit periods relatively longer, shorter, or the same as/than the circular orbits.


When you are ready, login to Blackboard and take Quiz Two.

You will get instant feedback on your score on Quiz Two (and your instructor will also be informed of your score). If your score is OK, you may proceed directly to the Essay Question Two on Blackboard. Otherwise, you might want to look at what you missed, ask your instructor about questions you missed, or review relevant parts of the unit.

Essay Question

Which of the following observations proves that the Earth goes around the Sun and not vice versa? Why were the other observations important discoveries that helped persuade people that the Earth does go around the Sun, along with all the other planets?
A. Phases of Venus.
B. Moons of Jupiter.
C. Sunspots and mountains on the Moon.
D. Stellar parallax.
E. Retrograde motion..

Don't forget to contribute to the discussion on Blackboard on one of the topics in this unit!