CJC Astronomy I

CJC Astronomy ICJC Astronomy I

Some Course BasicsSome Course Basics

Instructor - Dr. Wayne KeithInstructor - Dr. Wayne KeithContact info:Contact info:

Office HoursOffice HoursMcM Science 110CMcM Science 110CMWF: 9 – 11 amMWF: 9 – 11 amT: 9 – 10:30 amT: 9 – 10:30 amR: 2:30 – 5:30 pmR: 2:30 – 5:30 pm

[email protected]://www.mcm.edu/~keith.wayne (325) 793-3874(325) 793-3874


Textbook:Textbook: Pathways to Pathways to

Astronomy, by Astronomy, by Schneider and ArnySchneider and Arny

The textbook is The textbook is required!required!

I know it’s expensive, I know it’s expensive, but we’ll use it.but we’ll use it.

Some Course BasicsSome Course Basics Lecture:Lecture:

Monday & WednesdayMonday & Wednesday 5:00 pm to 6:25 pm5:00 pm to 6:25 pm

Attendance is required!Attendance is required! No make-up work for No make-up work for

missed quizzes. Four missed quizzes. Four daily grades will be daily grades will be dropped automatically.dropped automatically.

Attendance will be taken Attendance will be taken by roll sheets and/or in-by roll sheets and/or in-class quizzes.class quizzes.

10% of your grade!10% of your grade!


Daily GradeDaily Grade Attend classAttend class Bring astronomy-related Bring astronomy-related

current events to discuss current events to discuss at the beginning of class. at the beginning of class. (Something you can turn (Something you can turn in as hard-copy, even if in as hard-copy, even if it’s hand-written notes it’s hand-written notes about something you about something you saw on TV).saw on TV).

In-class quizzes based In-class quizzes based on reading assignments on reading assignments and lectures.and lectures.

Some Course BasicsSome Course Basics Reading AssignmentsReading Assignments I assign these in class, and they’re due by the next class I assign these in class, and they’re due by the next class

period.period. RELAX! They’re usually pretty short.RELAX! They’re usually pretty short. They’re required! Consider them part of your homework!They’re required! Consider them part of your homework!

Not reading them WILL affect your grade because:Not reading them WILL affect your grade because: I assume you’ve read them when you come to class. You’ll I assume you’ve read them when you come to class. You’ll

likely start feeling “lost” if you don’t read them!likely start feeling “lost” if you don’t read them! I ask questions about them during in-class quizzes!I ask questions about them during in-class quizzes! I ask questions about them on the exams!I ask questions about them on the exams! Some questions on the online quizzes are related to the reading Some questions on the online quizzes are related to the reading

assignments!assignments!

Some Course BasicsSome Course Basics Homework Questions/ProblemsHomework Questions/Problems These are your main homeworks for the class!These are your main homeworks for the class! Details:Details:

Will be announced in class and posted onlineWill be announced in class and posted online Due at the beginning of class on the date indicatedDue at the beginning of class on the date indicated

Late work will loose 5% per class periodLate work will loose 5% per class period

10% of your grade!10% of your grade!

Some Course BasicsSome Course Basics TESTS!TESTS! Three Term Exams:Three Term Exams:

Each is 15% of your grade.Each is 15% of your grade.

Final Exam:Final Exam: Worth 15% of your grade.Worth 15% of your grade. Cumulative (some new material, mostly previous material).Cumulative (some new material, mostly previous material). Includes post-testIncludes post-test

NO MAKE-UP FOR MISSED TESTS!NO MAKE-UP FOR MISSED TESTS! Only exceptionsOnly exceptions: Severe personal illness, or death in immediate : Severe personal illness, or death in immediate

family (official documentation required).family (official documentation required). Must notify me BEFORE CLASS that you will not be present!Must notify me BEFORE CLASS that you will not be present!

Extra CreditExtra Credit

There will be a few opportunities for “extra There will be a few opportunities for “extra credit” assignments over the semester.credit” assignments over the semester.

Most are announced near the end of the Most are announced near the end of the semester.semester.

The amount and type of credit varies and The amount and type of credit varies and will be announced with the assignment.will be announced with the assignment.

What Grade Will I Get?What Grade Will I Get?

Based on past experience, if you miss Based on past experience, if you miss more than six classes, you’ll fail the more than six classes, you’ll fail the course.course. If you don’t think you’ll be able to attend class If you don’t think you’ll be able to attend class

regularly, please drop the course!regularly, please drop the course! I expect everyone to make an effort to do well I expect everyone to make an effort to do well

in this classin this classYou don’t have to be a science major to do You don’t have to be a science major to do

well, grades will to a large extent reflect your well, grades will to a large extent reflect your level of effort in the class.level of effort in the class.

Other Common QuestionsOther Common Questions Is there math in this class?Is there math in this class?

Yes.Yes. I’m assuming you know how to add, subtract, multiply, I’m assuming you know how to add, subtract, multiply,

and divide.and divide. I’m assuming you know that in more “advanced” I’m assuming you know that in more “advanced”

math, letters are frequently used to stand for math, letters are frequently used to stand for numbers.numbers.

I’m assuming you know how to “solve” a simple I’m assuming you know how to “solve” a simple equation.equation.If you don’t know how to do this, please set aside If you don’t know how to do this, please set aside

about 30 minutes to come by my office during about 30 minutes to come by my office during office hours and let me tutor you on what to do.office hours and let me tutor you on what to do.

We will use We will use powerspowers and and logarithmslogarithms, but I’m not , but I’m not assuming you know or remember how to use these. assuming you know or remember how to use these. I’ll review them for you, in class, when we get to them.I’ll review them for you, in class, when we get to them.

Other Common QuestionsOther Common Questions

I freeze up when I see math, and I’m sure you I freeze up when I see math, and I’m sure you can’tcan’t help me with that! Can I still pass the help me with that! Can I still pass the class?class? If you’re willing to put in the time, I can probably help If you’re willing to put in the time, I can probably help

you more than you think, BUT…you more than you think, BUT… If you study the conceptual (non-math) questions on If you study the conceptual (non-math) questions on

the test reviews, and learn that material very well, the test reviews, and learn that material very well, attend classes, and do well on the quizzes, you’re attend classes, and do well on the quizzes, you’re likely to get a B! With some help on the extra credit, likely to get a B! With some help on the extra credit, you can even still get an A.you can even still get an A.

Introduction: Why Study Introduction: Why Study Astronomy?Astronomy?

For most of you, a For most of you, a science course is a science course is a “necessary evil” – you’re “necessary evil” – you’re required to take one.required to take one.

Astronomy is one of the Astronomy is one of the coolest sciences to take, coolest sciences to take, because you study things because you study things outside of everyday outside of everyday experience!experience!

It’s like taking a break It’s like taking a break from the “real world” to from the “real world” to study the fantastic for a study the fantastic for a while!while!

Introduction: Why Study Introduction: Why Study Astronomy? Astronomy?

Here are some of the benefits Here are some of the benefits of studying a science:of studying a science: It improves your problem It improves your problem

solving skills.solving skills. It improves your critical It improves your critical

thinking skills.thinking skills. Both are related to Both are related to

competence on the job, competence on the job, something employers value.something employers value.

These skills improve your These skills improve your leadership ability.leadership ability.

Improves your ability to Improves your ability to express yourself.express yourself.

It helps guard against “being It helps guard against “being taken” by a pseudoscientific taken” by a pseudoscientific scam! (The world is scam! (The world is filledfilled with with these.)these.)

Introduction: Why Study Introduction: Why Study Astronomy?Astronomy?

You’d probably be You’d probably be surprised just how many surprised just how many people find astronomy people find astronomy interesting in small doses.interesting in small doses. You’ll learn about the sky You’ll learn about the sky

and the constellations.and the constellations. You’ll learn about LOTS of You’ll learn about LOTS of

other cool things, like:other cool things, like: How the sun will KILL US How the sun will KILL US

ALL!ALL! Exploding stars!Exploding stars! Exploding galaxies!Exploding galaxies! Black Holes!Black Holes! And much more!And much more!

First Quiz!First Quiz!

Take the pretest (not graded)Take the pretest (not graded)

On the back page, write a short statement On the back page, write a short statement about yourself. Suggested topics are about yourself. Suggested topics are listed, but are not required.listed, but are not required.

Your name (at least) must be legible for Your name (at least) must be legible for you to receive credit.you to receive credit.

The Scientific MethodThe Scientific Method

Astronomy is a Astronomy is a physical science.physical science. Astronomers use the Astronomers use the

scientific methodscientific method to to answer questions answer questions about objects found in about objects found in outer space.outer space.

What is the scientific What is the scientific method? How does it method? How does it work?work?

How Do We Gain Knowledge?How Do We Gain Knowledge?

Two basic methods:Two basic methods:RevelationRevelationExperimentationExperimentation

Revelation vs. ExperimentationRevelation vs. Experimentation

Revelation:Revelation: Somebody gives us the Somebody gives us the

information.information. Believe or disbelieve Believe or disbelieve

information based on our information based on our opinion of the validity of the opinion of the validity of the source.source.

Very common.Very common. Examples:Examples:

College Lecture CourseCollege Lecture Course A Religious TextA Religious Text

Experimentation:Experimentation: We gather the information We gather the information

ourselves.ourselves. Believe or disbelieve based Believe or disbelieve based

on our opinion of the on our opinion of the validity of the data.validity of the data.

Examples:Examples: The Scientific MethodThe Scientific Method Comparative ShoppingComparative Shopping

ExamplesExamples

““Careful! Hot!”Careful! Hot!” RevelationRevelation: warning from : warning from

parent.parent. Information gainedInformation gained: the : the

object is hot. Touching it object is hot. Touching it will hurt.will hurt.

Possible conclusionsPossible conclusions:: Mom/Dad is wrong (invalid Mom/Dad is wrong (invalid

source); go ahead and source); go ahead and touch.touch.

Mom/Dad is right; don’t Mom/Dad is right; don’t touch.touch.

ExamplesExamples

““OUCH!”OUCH!” ExperimentationExperimentation: You : You

touch the hot object touch the hot object yourself.yourself.

Information gainedInformation gained: : Object is hot. Object is hot. Touching it hurt.Touching it hurt.

ConclusionsConclusions:: Data are valid – object Data are valid – object

isis hot. hot. Don’t touch again!Don’t touch again!

The Basic Idea…The Basic Idea…

When you find out something by learning it When you find out something by learning it from someone else, that’s from someone else, that’s revelationrevelation..

When you find out something by figuring it When you find out something by figuring it out for yourself, that’s out for yourself, that’s experimentationexperimentation..


The Scientific Method is a way of The Scientific Method is a way of answering questions through answering questions through experimentation.experimentation.

First StepFirst Step: Ask a question you want : Ask a question you want answered (in science, it is typically a answered (in science, it is typically a question about nature.)question about nature.)


Step Two:Step Two: Design and Design and conduct experiments conduct experiments related to the related to the question. Collect the question. Collect the resulting data.resulting data.


Step ThreeStep Three: Use the : Use the data to formulate a data to formulate a hypothesis.hypothesis.

Hypothesis:Hypothesis: In In science, a statement science, a statement of how something is of how something is believed to work.believed to work.

The Scientific MethodThe Scientific Method Hypothesis must be Hypothesis must be falsifiable!falsifiable!

Must make a prediction that can actually be tested through Must make a prediction that can actually be tested through further experiments!further experiments!

Step Four:Step Four: Use hypothesis to make predictions, and Use hypothesis to make predictions, and conduct experiments to test predictions.conduct experiments to test predictions. Experiments match predictions, hypothesis is upheld.Experiments match predictions, hypothesis is upheld. Experiments don’t match predictions, hypothesis must be Experiments don’t match predictions, hypothesis must be

modified or discarded.modified or discarded. Modifying hypothesis based on data Modifying hypothesis based on data is a return tois a return to Step Step

TwoTwo. So process is ongoing.. So process is ongoing.

Summary of StepsSummary of Steps

1. Ask a Question1. Ask a Question

2. Gather Data About The Question2. Gather Data About The Question

3. Formulate a Hypothesis using the 3. Formulate a Hypothesis using the DataData

4. See if predictions from Hypothesis 4. See if predictions from Hypothesis match results from further match results from further experiments (i.e. collect more data).experiments (i.e. collect more data).


Always possible future data could Always possible future data could contradict hypothesis – contradict hypothesis – no hypothesis is no hypothesis is ever final.ever final.

Science can’t Science can’t proveprove what is true! It can what is true! It can only only proveprove what is false! what is false! Intelligent Intelligent skepticism is very important.skepticism is very important.

Theories vs. LawsTheories vs. Laws

A hypothesis that can, A hypothesis that can, in principle, be in principle, be explained with a explained with a mathematical relation mathematical relation is a is a scientific lawscientific law..

A A collection collection of of hypotheses that hypotheses that attempt to explain a attempt to explain a natural phenomenon natural phenomenon is a is a scientific theoryscientific theory..

Laws Were Made To Be Broken!Laws Were Made To Be Broken!

HypothesisHypothesis: The pressure : The pressure in a gas is proportional to in a gas is proportional to the temperature of the the temperature of the gas divided by the gas divided by the volume the gas takes up.volume the gas takes up.

Called the Called the Ideal Gas Ideal Gas LawLaw, and is a , and is a lawlaw because it can be because it can be expressed expressed mathematically:mathematically:

(Pressure) = (constant) x (temperature) / (volume)

or PV = nRT

Laws Were Made To Be Broken!Laws Were Made To Be Broken!

Experiments show that if Experiments show that if you plug in temperatures you plug in temperatures and volumes, the and volumes, the pressures only match pressures only match reality for high reality for high temperatures and low temperatures and low densities (little gas in a densities (little gas in a large volume)!large volume)!

The Ideal Gas Law is The Ideal Gas Law is not not accurateaccurate for gasses at for gasses at low temperatures or at low temperatures or at high densities.high densities.

Yet still referred to as a scientific law!

The Scientific Method At WorkThe Scientific Method At Work

Step 1: Formulate A Step 1: Formulate A QuestionQuestion Why does the sun Why does the sun

shine?shine?

Step 2: Design and Step 2: Design and Experiment / Make Experiment / Make ObservationsObservations What else gives off What else gives off

light and heat?light and heat? Fire!Fire!


Step 3: Formulate A Step 3: Formulate A HypothesisHypothesis The sun is made from The sun is made from

wood. It shines wood. It shines because it is on fire.because it is on fire.


Step 4: Collect more data and compare to Step 4: Collect more data and compare to hypothesis.hypothesis.By observing the sun we can find out more By observing the sun we can find out more

things about it.things about it. It puts out as much light as a It puts out as much light as a

400,000,000,000,000,000,000,000,000 watt 400,000,000,000,000,000,000,000,000 watt light bulb.light bulb.

By observing fires we could find out that to put By observing fires we could find out that to put out this much light, we would have to burn 73 out this much light, we would have to burn 73 million trillion pounds of wood each second.million trillion pounds of wood each second.


The sun “weighs” 6 million trillion trillion The sun “weighs” 6 million trillion trillion pounds.pounds.73 million trillion pounds of the sun would 73 million trillion pounds of the sun would

have to “burn” each second to produce all the have to “burn” each second to produce all the sunlight we see…sunlight we see…

The sun will “burn out” in about 2,000 years.The sun will “burn out” in about 2,000 years.

The Scientific Method At WorkThe Scientific Method At Work This creates a problem.This creates a problem. 2,000 years ago was the 2,000 years ago was the

height of the Roman height of the Roman Empire – we Empire – we knowknow the the sun was putting out light sun was putting out light then (observation based then (observation based on literature from back on literature from back then).then).

If our hypothesis is true, If our hypothesis is true, the sun would have the sun would have burned out a long time burned out a long time ago!ago!

The hypothesis isn’t The hypothesis isn’t correct!correct!

What Do We Do Now?What Do We Do Now? Now we need to make more observations to Now we need to make more observations to

come up with a new hypothesis.come up with a new hypothesis. And the process begins again. And keeps And the process begins again. And keeps

going.going. After hundreds of years of this processAfter hundreds of years of this process

Here’s what we’ve Here’s what we’ve eliminated:eliminated: The sun is made mostly of: Oil, Coal, Methane, CalciumThe sun is made mostly of: Oil, Coal, Methane, Calcium The sun’s energy comes from: Chemical Reactions, The sun’s energy comes from: Chemical Reactions,

Gravitational Contraction.Gravitational Contraction. And here’s where we are (the current hypothesis):And here’s where we are (the current hypothesis):

The sun is made of hydrogen and helium.The sun is made of hydrogen and helium. It shines because of a nuclear fusion reaction happening at It shines because of a nuclear fusion reaction happening at

its core.its core.

PseudosciencePseudoscience

What if I’d “fixed” my failed hypothesis by What if I’d “fixed” my failed hypothesis by doing this:doing this:New Hypothesis: The sun is made of a special New Hypothesis: The sun is made of a special

type of wood that burns 10,000 times brighter type of wood that burns 10,000 times brighter and 10,000 times slower than “earth wood.”and 10,000 times slower than “earth wood.”

Now the sun will take billions of years to “burn Now the sun will take billions of years to “burn up” so everything is fine.up” so everything is fine.

PseudosciencePseudoscience

Currently, that hypothesis is (nearly) Currently, that hypothesis is (nearly) impossible to test – we can’t land a probe impossible to test – we can’t land a probe on the sun and test it.on the sun and test it.

Our hypothesis is now Our hypothesis is now pseudosciencepseudoscience..We have forced the scientific method to give We have forced the scientific method to give

us the answer we want.us the answer we want.We have ignored any evidence that disagrees We have ignored any evidence that disagrees

with our idea.with our idea.

Occam’s RazorOccam’s Razor

The principle of OCCAM’S RAZOR:The principle of OCCAM’S RAZOR:When you have two competing theories that When you have two competing theories that

both explain something equally well, the both explain something equally well, the simpler theory will usually be the correct one.simpler theory will usually be the correct one.

More on PseudoscienceMore on Pseudoscience

Modifying a hypothesis based on Modifying a hypothesis based on new observationsnew observations

= The Scientific Method = The Scientific Method

Ignoring or manipulating Ignoring or manipulating observations to fit a hypothesisobservations to fit a hypothesis

= Pseudoscience= Pseudoscience

Common Examples of Common Examples of PseudosciencePseudoscience

ASTROLOGYASTROLOGY Just Just somesome of the of the

evidence against it:evidence against it: Compatible-sign Compatible-sign

marriages have the marriages have the same divorce rate as same divorce rate as the general population.the general population.

Astrologers didn’t Astrologers didn’t predict the dwarf planet predict the dwarf planet Eris.Eris.

Sun and moon given Sun and moon given same “weight” as same “weight” as planets.planets.


““Face on Mars”Face on Mars” Later observations by Later observations by

Mars Global Surveyor Mars Global Surveyor show it’s just a show it’s just a mountain rangemountain range

““Moon hoax” hoaxMoon hoax” hoax Uses a multitude of Uses a multitude of

easily-debunked easily-debunked “evidence” to try to “evidence” to try to show humans didn’t go show humans didn’t go to the moon.to the moon.


Read about these and many others in depth on Read about these and many others in depth on Phil Plait’s “Bad Astronomy” web site:Phil Plait’s “Bad Astronomy” web site:

www.badastronomy.comwww.badastronomy.com

(don’t let its educational value fool you, it’s really quite (don’t let its educational value fool you, it’s really quite entertaining!)entertaining!)

The Ongoing ProcessThe Ongoing Process

Most of what you’ll learn in this course Most of what you’ll learn in this course you’ll hear from me (Knowledge gained by you’ll hear from me (Knowledge gained by revelation)…revelation)…

BUT most of what I’m telling you has been BUT most of what I’m telling you has been deduced using the process we’ve talked deduced using the process we’ve talked about today (Knowledge gained by about today (Knowledge gained by experimentation).experimentation).

AnnouncementsAnnouncements

Please note that the lab WILL meet this Please note that the lab WILL meet this week, after class Wednesday.week, after class Wednesday.

There is no lab manual, handouts will be There is no lab manual, handouts will be provided for the labs.provided for the labs.

For Next timeFor Next time

Read Units 1 and 2 (calm down, it’s only Read Units 1 and 2 (calm down, it’s only 15 pages).15 pages).

Homework 1 – Due Monday January 29Homework 1 – Due Monday January 29Unit 1: Review Questions 2 and 3, Test Unit 1: Review Questions 2 and 3, Test

yourself 1yourself 1Unit 2: Problem 3, Test yourself 1Unit 2: Problem 3, Test yourself 1Unit 5: Problem 1, Test yourself 1Unit 5: Problem 1, Test yourself 1Unit 6: Problem 1, Test yourself 1 and 3Unit 6: Problem 1, Test yourself 1 and 3

CJC Astronomy I

Documents

Transcript of CJC Astronomy I