Unit 1 : Activity 1 : Sunrise, Sunset, Star-rise, Star-set : Crescent Venus : The Wanderers in our Sky : Unit Exam









Unit 1: 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 EveningStar.

Brief summary of Unit One:

Topics we have covered include rising and setting of the Sun and stars, the phases of Venus, the apparent motions of the planets against the background stars, and synodic versus sidereal periods of the planets.

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

You observe a given star rise at a certain angle with respect to the horizon from your hometown in January. Two months later, will the star rise with the same angle to the horizon? Will it rise at the same time?

Practice Question Two

Over one night you will see Mars move East relative to the background stars (prograde), then West (retrograde), then East again (prograde). True or False? Explain.

 

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

You will get instant feedback on your score on Quiz One (and your instructor will also be informed of your score). If your score is OK, you may proceed directly to the Essay Question One 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

Suppose you observe Mars at midnight, and it is due South from where you are. Which of the following statements is or are false, and what is wrong with the false statement(s)?
A. Mars is exhibiting retrograde motion around the date of your observation.
B. Mars would appear as a crescent if viewed through a telescope at this time.
C. Mars is farther from the earth at the time of your observation than it usually or on average is.
Note: It is not enough to say "the statement is false"; you need to explain what would be needed to make it correct.

An example of how to answer this kind of question is:
The moon appears to us as a circle with a dark crescent reducing the bright part to less than a full circular disk. That means that the shadow of the Earth is covering a little less than half of its surface. Good answers: The statement cannot be true because a circular shadow cannot produce the bright gibbous appearance.The statement is not true because at this phase the Earth, Moon and Sun are not lined up.

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