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Astronomy & Astrophysics
Michael Reid

Getting the Most Out ofAST 101/201 Dr. M.A. Reid What's This Guide For? Students in AST 101/201 often ask what they can do to ensure that they get a good mark in the course. The simple answer is that you should try hard and focus on developing good study habits. Our goal in this guide is to explain what “good study habits” are, as pertains specifically to this course. Lectures Let's get this out of the way: traditional lectures are a bad way to learn. Numerous studies have shown that most students retain a pretty tiny fraction of what they hear in lectures, and they don't retain it for long. Worse, the whole format is poor: you sit in chairs, I stand on a stage; you sit quietly, I do all the talking; I decide what's important. If, as Marshall McLuhan said, “the medium is the message”, then the message that traditional lectures send is that you should be passive, accept authority without question, never set your own learning agenda, and never have an original thought. I don't want you to endure traditional lectures. There is, however, the small problem that there are 1350 of you and only one of me. It's hard to make a personal connection with each of you, to grant you all educational autonomy. But, as long as we are stuck with the lecture format, I will try to meet you halfway toward a better way of learning. I will try never to blather on at the front of the room for too long. I ask that you try not to sit passively and write down everything that I say. So what should you do instead? Here are some ideas: Do the readings before class. This will serve two functions: it will remind you that you don't need to spend the lecture scribbling down 'facts'--they're all there for you in the book. It will also get you thinking, help you to find topics that interest you, and get you asking questions. Why not write some of those questions down before you come to class? Why don't we call Pluto a planet any more? Could people survive on Mars? Are we alone in the cosmos? How would I figure any of this stuff out, anyway? Print the notes out beforehand and bring them to class. This will again reassure you that all the 'facts' really are written down. You can add notes here and there if you like, but you don't need to take pages and pages of them. Ask questions. Here's the truth about this course: there is no mundane reason that you need to know any of this stuff. Knowing whether the universe will end in fire or in ice isn't going to get you a job as an accountant. You can safely plan to learn only the things that interest you in this course. That means you should ask questions. I dislike talking about things most of you don't want to know. So tell me what you want to know. Feel free to stop the lecture at any point with a question. And try to be patient when others do the same. Do the clicker quizzes honestly. The clicker quizzes are designed to break the monotony of a lecture and to give you an opportunity to use what you learn so you don't forget it. I have loads of data to show that students who do the clicker quizzes—even if they get them wrong—do better on the final exam than those who don't. Do them. Don't worry if you miss a few here and there. Each one is worth about 0.05% of your final mark, so you can go to the bathroom without asking your friend to cheat for you. Shut your cell phone off. Stay off Twitter. Tell the guy beside you to stop watching YouTube on his laptop. If you don't find the class interesting, ask a question about something that interests you or just leave. Even if you miss a few clicker quizzes, it's not going to have a huge impact on your mark. Let those who want to pay attention do so without hindrance. Record the lecture. Go ahead. If this helps you resist the temptation to sit there and scribble notes all class instead of interacting, then do it. Studying for Tests and Exams Here's the thing: I don't care if you can memorize long lists of facts. We can all do that. Memorizing lists of things is important when you're learning a foreign language, but not when you're learning a science. So skip that whole study strategy—you won't remember facts you 'cram' before the test anyway. When it comes to preparing for tests and exams, I want you to focus on three goals: Developing a general familiarity with the cosmos. As far as facts go, I'd like you to know some important ones. For example, that the Earth orbits the Sun, that the Sun is not 'on fire', that there are eight planets in the solar system and many more dwarf planets, and that the nearest star (beyond the Sun) is hundreds of thousands of times further from us than the Sun itself is. I don't care if you know the diameter of the Earth in kilometers, the exact mass which is converted to energy during the proton- proton chain, or the mass of the Sun to three decimal places. Those are 'factoids'--trivial pieces of information which can be useful, but can also be looked up easily when needed. I will never test you on factoids. Developing your conceptual understanding of the cosmos. Again, I don't care about memorizing facts. I don't want you to finish this class having memorized a lot of things you don't really understand. I want you to transform your understanding. Focus your studying on things you can talk through with your friends. How does the carbon cycle work and why do we care? What's the general overall shape of the solar system and what does this tell us about how it formed? If you wanted to find another Earth somewhere else in the galaxy, how could you do it? Is it even possible? Has anyone done it? These are important concepts. So, keep this golden rule in mind: concepts before facts, and facts before factoids. Try to think in pictures. No, really. You'll kick yourself after the first midterm if you don't heed this message. You'll notice that the lecture notes are full of pictures and diagrams. That's because a whole lot of the work astronomers do consists of taking and interpreting pictures. So pay attention to them! On the tests, you're going to be asked to draw things: the solar system from different perspectives, the relationship between the seasons and the tilt of Earth's axis, the different ways to measure distances in space, and so on. If you can think these things through in pictures, you'll remember them much more easily. But don't worry—we don't expect you to be an artist. Sample Questions Let's consider an example test question. During this course, I will tell you that Earth is more tectonically active than Mars because Earth has a smaller surface-area-to-volume ratio. Having more surface area exposed to space per cubic meter of rock it contains means that Mars radiates heat into space more efficiently than Earth does and, hence, cools faster. This has all sorts of cool effects: it means that Mars solidified a long time ago (we think), so it doesn't have an internal dynamo and therefore has a very feeble planetary magnetic field. That means it'd be dangerous to live there because you'd be hammered by high-energy solar wind particles. What should you do with this information? First, try to identify the facts. The facts include: Mars is smaller than Earth, Mars has a higher surface-area-to-volume ratio than Earth, Mars cools faster than Earth, and Earth is more tectonically active than Mars. Next, try to pick out the concept which makes sense of the facts. The concept here is that smaller planets cool more efficiently because they have higher surface-area-to-volume ratios. Try to talk the concept through with a friend. Can you think of other situations like this? If I put a bowling ball and a tiny ball-bearing in the oven, heated them to 300 C, then took them out, which one would you prefer to pick up with your bare hand after 30s? Why? Next, identify and plan to ignore the factoids. Factoids would include the exact diameters or exact surface-area-to-volume ratios of the two planets. I didn't bother to mention any factoids in the example, but you'll find them in your text. The nervous student might be tempted to memorize them. Don't bother. Focus on learning how to apply the concept in as many situations as you can. How would you be tested on this concept? Here's a sample conceptual question: 1. Planet X has a larger surface-area-to-volume ratio than planet Y. Which of the following conditions might be caused by this difference? a) Planet X would have prettier birds b) Planet X would have more active volcanoes c) Planet X would have fewer earthquakes d) Planet X would be older To correctly answer this question, you need to know what it means for a planet to have a large surface- area-to-volume ratio. You also need to understand the relationship between this ratio and a planet's level of tectonic activity. Does a higher ratio lead to more volcanoes? Fewer earthquakes? Why? Note that knowing a bunch of factoids won't give you the answer here, because we're not even asking about specific planets. The question is asking you to apply the concept in a general case. This is the kind of learning we are trying to encourage. In this case, if you know a relevant fact—that Earth is more tectonically active than Mars—but not the concept—that this is because Earth has a smaller surface-area-to-volume ratio—you might be able to reason backward to the concept during the exam. On the other hand, you might not! Even if you do manage to reason from the fact to the concept during the exam, you probably won't be confident of your answer. If you only memorized a factoid—the exact diameters of Earth and Mars—you will be totally lost on this question. Here's a question on this topic which are you unlikely to be asked, because it only tests rote memorization: 1. Which of the following planets is most tectonically active? a) Earth b) Mars c) the Sun d) Europa How do you decide which facts to memorize? There is no hard-and-fast rule you can apply. You have to develop a sense for which facts are most essential. Try asking yourself “Does knowing this fact really help me understand the cosmos better?” or “Would not knowing this fact reduce my understanding of the cosmos?” For example, one of our goals is to give you a sense of how big space is. As such, it helps if you know some basic information about the typical sizes of astronomical objects and the typical distances between them. You should know the approximate distance between the Earth and the Sun in some sensible units, such as light-minutes or astronomical units (AU). Knowing this distance in centimeters would be a factoid—it's just some huge number that means nothing to you and does nothing to shape your understanding. How might this fact about the distance between the Earth and the Sun come up in a test question? We might ask something like: 1. How long does light take to go from Earth to the Sun? a) a few light minutes b) a few minutes c) about a year d) a few light years We would not ask: 1. How long does a ray of light take to go from Earth to the Sun? a) 8.1 minutes b) 8.2 minutes c) 8.3 minutes d) 8.4 minutes To answer the first question correctly, you need to know that it takes light a few minutes to get from the Earth to the Sun. This is a generally useful fact. You know that the speed of light is enormous and you will also know, by the end of the course, that the average distance between stars within a galaxy is several light-years. So, knowing that the Earth is a few light-minutes from the Sun tells you that Earth is enormously far from the Sun (thanks to the enormous speed of light), but that we are much, much closer to the Sun than we are to the next nearest star. Knowledge of this original fact helps you to calibrate your mental model of the universe, so it's a useful fact. How to Study You have at least three sources from which to study for this course: the course notes published online, the textbook, and any notes you took in class. Let the course notes be your guide to what is and is not important. We are not going to test you on concepts not covered in class. Here is a good approach to studying for a test: 1. Go through the course notes and make a list of all of the important concepts. Any concept illustrated with a diagram or related to a highlighted word is probably important. 2. Prioritize this list. Which concepts give you the most trouble? 3. Review the sections of the notes pertaining to the concepts you identified as most difficult. Make a written summary of each concept in your own words that you can keep reviewing. 4. Go back to the textbook and read through the sections which explain those difficult concepts. Add to your notes on each concept as needed. 5. For each concept, try to think of a few questions you might be asked which would test your understanding of that concept. Make sure you can answer those questions. 6. Identify any important facts associated with each concept that you think you might need to remember. Abad way to study would be to simply re-read all of the sections of the textbook which appear on the reading list. In so doing, you do not distinguish between important and unimportant concepts, nor concepts you understand well and those you don't. How Will You Know You're Ready for a Test? There are many good ways to assess your level of preparation for the test or exam. They includ
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