CJC Astronomy I

1. CJC Astronomy I

2. Some Course Basics • Instructor - Dr. Wayne Keith • Contact info: • Office Hours • McM Science 110C • MWF: 9 – 11 am • T: 9 – 10:30 am • R: 2:30 – 5:30 pm • keith.wayne@mcm.edu • http://www.mcm.edu/~keith.wayne • (325) 793-3874

3. Some Course Basics • Textbook: • Pathways to Astronomy, by Schneider and Arny • The textbook is required! • I know it’s expensive, but we’ll use it.

4. Some Course Basics • Lecture: • Monday & Wednesday • 5:00 pm to 6:25 pm • Attendance is required! • No make-up work for missed quizzes. Four daily grades will be dropped automatically. • Attendance will be taken by roll sheets and/or in-class quizzes. • 10% of your grade!

5. Some Course Basics • Daily Grade • Attend class • Bring astronomy-related current events to discuss at the beginning of class. (Something you can turn in as hard-copy, even if it’s hand-written notes about something you saw on TV). • In-class quizzes based on reading assignments and lectures.

6. Some Course Basics • Reading Assignments • I assign these in class, and they’re due by the next class period. • RELAX! They’re usually pretty short. • They’re required! Consider them part of your homework! • Not reading them WILL affect your grade because: • I assume you’ve read them when you come to class. You’ll likely start feeling “lost” if you don’t read them! • I ask questions about them during in-class quizzes! • I ask questions about them on the exams! • Some questions on the online quizzes are related to the reading assignments!

7. Some Course Basics • Homework Questions/Problems • These are your main homeworks for the class! • Details: • Will be announced in class and posted online • Due at the beginning of class on the date indicated • Late work will loose 5% per class period • 10% of your grade!

8. Some Course Basics • TESTS! • Three Term Exams: • Each is 15% of your grade. • Final Exam: • Worth 15% of your grade. • Cumulative (some new material, mostly previous material). • Includes post-test • NO MAKE-UP FOR MISSED TESTS! • Only exceptions: Severe personal illness, or death in immediate family (official documentation required). • Must notify me BEFORE CLASS that you will not be present!

9. Extra Credit • There will be a few opportunities for “extra credit” assignments over the semester. • Most are announced near the end of the semester. • The amount and type of credit varies and will be announced with the assignment.

10. What Grade Will I Get? • Based on past experience, if you miss more than six classes, you’ll fail the course. • If you don’t think you’ll be able to attend class regularly, please drop the course! • I expect everyone to make an effort to do well in this class • You don’t have to be a science major to do well, grades will to a large extent reflect your level of effort in the class.

11. Other Common Questions • Is there math in this class? • Yes. • I’m assuming you know how to add, subtract, multiply, and divide. • I’m assuming you know that in more “advanced” math, letters are frequently used to stand for numbers. • I’m assuming you know how to “solve” a simple equation. • If you don’t know how to do this, please set aside about 30 minutes to come by my office during office hours and let me tutor you on what to do. • We will use powers and logarithms, but I’m not assuming you know or remember how to use these. I’ll review them for you, in class, when we get to them.

12. Other Common Questions • I freeze up when I see math, and I’m sure you can’t help me with that! Can I still pass the class? • If you’re willing to put in the time, I can probably help you more than you think, BUT… • If you study the conceptual (non-math) questions on the test reviews, and learn that material very well, attend classes, and do well on the quizzes, you’re likely to get a B! With some help on the extra credit, you can even still get an A.

13. Introduction: Why Study Astronomy? • For most of you, a science course is a “necessary evil” – you’re required to take one. • Astronomy is one of the coolest sciences to take, because you study things outside of everyday experience! • It’s like taking a break from the “real world” to study the fantastic for a while!

14. Introduction: Why Study Astronomy? • Here are some of the benefits of studying a science: • It improves your problem solving skills. • It improves your critical thinking skills. • Both are related to competence on the job, something employers value. • These skills improve your leadership ability. • Improves your ability to express yourself. • It helps guard against “being taken” by a pseudoscientific scam! (The world is filled with these.)

15. Introduction: Why Study Astronomy? • You’d probably be surprised just how many people find astronomy interesting in small doses. • You’ll learn about the sky and the constellations. • You’ll learn about LOTS of other cool things, like: • How the sun will KILL US ALL! • Exploding stars! • Exploding galaxies! • Black Holes! • And much more!

16. First Quiz! • Take the pretest (not graded) • On the back page, write a short statement about yourself. Suggested topics are listed, but are not required. • Your name (at least) must be legible for you to receive credit.

17. The Scientific Method • Astronomy is a physical science. • Astronomers use the scientific method to answer questions about objects found in outer space. • What is the scientific method? How does it work?

18. How Do We Gain Knowledge? • Two basic methods: • Revelation • Experimentation

19. Revelation: Somebody gives us the information. Believe or disbelieve information based on our opinion of the validity of the source. Very common. Examples: College Lecture Course A Religious Text Experimentation: We gather the information ourselves. Believe or disbelieve based on our opinion of the validity of the data. Examples: The Scientific Method Comparative Shopping Revelation vs. Experimentation

20. Examples • “Careful! Hot!” • Revelation: warning from parent. • Information gained: the object is hot. Touching it will hurt. • Possible conclusions: • Mom/Dad is wrong (invalid source); go ahead and touch. • Mom/Dad is right; don’t touch.

21. Examples • “OUCH!” • Experimentation: You touch the hot object yourself. • Information gained: Object is hot. Touching it hurt. • Conclusions: • Data are valid – object is hot. • Don’t touch again!

22. The Basic Idea… • When you find out something by learning it from someone else, that’s revelation. • When you find out something by figuring it out for yourself, that’s experimentation.

23. The Scientific Method • The Scientific Method is a way of answering questions through experimentation. • First Step: Ask a question you want answered (in science, it is typically a question about nature.)

24. The Scientific Method • Step Two: Design and conduct experiments related to the question. Collect the resulting data.

25. The Scientific Method • Step Three: Use the data to formulate a hypothesis. • Hypothesis: In science, a statement of how something is believed to work.

26. The Scientific Method • Hypothesis must be falsifiable! • Must make a prediction that can actually be tested through further experiments! • Step Four: Use hypothesis to make predictions, and conduct experiments to test predictions. • Experiments match predictions, hypothesis is upheld. • Experiments don’t match predictions, hypothesis must be modified or discarded. • Modifying hypothesis based on data is a return toStep Two. So process is ongoing.

27. Summary of Steps 1. Ask a Question 2. Gather Data About The Question 3. Formulate a Hypothesis using the Data 4. See if predictions from Hypothesis match results from further experiments (i.e. collect more data).

28. The Scientific Method • Always possible future data could contradict hypothesis – no hypothesis is ever final. • Science can’t prove what is true! It can only prove what is false! • Intelligent skepticism is very important.

29. A hypothesis that can, in principle, be explained with a mathematical relation is a scientific law. A collection of hypotheses that attempt to explain a natural phenomenon is a scientific theory. Theories vs. Laws

30. Laws Were Made To Be Broken! • Hypothesis: The pressure in a gas is proportional to the temperature of the gas divided by the volume the gas takes up. • Called the Ideal Gas Law, and is a law because it can be expressed mathematically: (Pressure) = (constant) x (temperature) / (volume) or PV = nRT

31. Laws Were Made To Be Broken! • Experiments show that if you plug in temperatures and volumes, the pressures only match reality for high temperatures and low densities (little gas in a large volume)! • The Ideal Gas Law is not accurate for gasses at low temperatures or at high densities. Yet still referred to as a scientific law!

32. The Scientific Method At Work • Step 1: Formulate A Question • Why does the sun shine? • Step 2: Design and Experiment / Make Observations • What else gives off light and heat? • Fire!

33. The Scientific Method At Work • Step 3: Formulate A Hypothesis • The sun is made from wood. It shines because it is on fire.

34. The Scientific Method At Work • Step 4: Collect more data and compare to hypothesis. • By observing the sun we can find out more things about it. • It puts out as much light as a 400,000,000,000,000,000,000,000,000 watt light bulb. • By observing fires we could find out that to put out this much light, we would have to burn 73 million trillion pounds of wood each second.

35. The Scientific Method At Work • The sun “weighs” 6 million trillion trillion pounds. • 73 million trillion pounds of the sun would have to “burn” each second to produce all the sunlight we see… • The sun will “burn out” in about 2,000 years.

36. The Scientific Method At Work • This creates a problem. • 2,000 years ago was the height of the Roman Empire – we know the sun was putting out light then (observation based on literature from back then). • If our hypothesis is true, the sun would have burned out a long time ago! • The hypothesis isn’t correct!

37. What Do We Do Now? • Now we need to make more observations to come up with a new hypothesis. • And the process begins again. And keeps going. • After hundreds of years of this process • Here’s what we’ve eliminated: • The sun is made mostly of: Oil, Coal, Methane, Calcium • The sun’s energy comes from: Chemical Reactions, Gravitational Contraction. • And here’s where we are (the current hypothesis): • The sun is made of hydrogen and helium. • It shines because of a nuclear fusion reaction happening at its core.

38. Pseudoscience • What if I’d “fixed” my failed hypothesis by doing this: • New Hypothesis: The sun is made of a special type of wood that burns 10,000 times brighter and 10,000 times slower than “earth wood.” • Now the sun will take billions of years to “burn up” so everything is fine.

39. Pseudoscience • Currently, that hypothesis is (nearly) impossible to test – we can’t land a probe on the sun and test it. • Our hypothesis is now pseudoscience. • We have forced the scientific method to give us the answer we want. • We have ignored any evidence that disagrees with our idea.

40. Occam’s Razor • The principle of OCCAM’S RAZOR: • When you have two competing theories that both explain something equally well, the simpler theory will usually be the correct one.

41. More on Pseudoscience • Modifying a hypothesis based on new observations = The Scientific Method • Ignoring or manipulating observations to fit a hypothesis = Pseudoscience

42. Common Examples of Pseudoscience • ASTROLOGY • Just some of the evidence against it: • Compatible-sign marriages have the same divorce rate as the general population. • Astrologers didn’t predict the dwarf planet Eris. • Sun and moon given same “weight” as planets.

43. Common Examples of Pseudoscience • “Face on Mars” • Later observations by Mars Global Surveyor show it’s just a mountain range • “Moon hoax” hoax • Uses a multitude of easily-debunked “evidence” to try to show humans didn’t go to the moon.

44. Common Examples of Pseudoscience • Read about these and many others in depth on Phil Plait’s “Bad Astronomy” web site: www.badastronomy.com (don’t let its educational value fool you, it’s really quite entertaining!)

45. The Ongoing Process • Most of what you’ll learn in this course you’ll hear from me (Knowledge gained by revelation)… • BUT most of what I’m telling you has been deduced using the process we’ve talked about today (Knowledge gained by experimentation).

46. Announcements • Please note that the lab WILL meet this week, after class Wednesday. • There is no lab manual, handouts will be provided for the labs.

47. For Next time • Read Units 1 and 2 (calm down, it’s only 15 pages). • Homework 1 – Due Monday January 29 • Unit 1: Review Questions 2 and 3, Test yourself 1 • Unit 2: Problem 3, Test yourself 1 • Unit 5: Problem 1, Test yourself 1 • Unit 6: Problem 1, Test yourself 1 and 3