Charles Hakes Fort Lewis College1. Charles Hakes Fort Lewis College2 The View from Earth and Physics...

Charles HakesFort Lewis College 1


The View from Earth

and

Physics Background


Outline

Logistics Review clicker checkup The view from Earth Some General Science background


Class Introduction

• Class Web Site is: http://faculty.fortlewis.edu/hakes_c/

• Also you will need: http://www.masteringastronomy.com

• ASTRONOMYHAKESF11

http://faculty.fortlewis.edu/hakes_c/

http://www.masteringastronomy.com/


Logistics

• Homework Study sessions…• (Looking for tutor)• Login Issues?

• Manila Folder format - today, write your full name on the tab, and large “call name” on the front.


Logistics

• Tentative evening activity for week two...


Class Objective


Class Objective

• To gain a general understanding of the contents of your universe and how it works.


Figure 18.1Arrow of Time


Class Objective


• To learn about some of the physical laws that control the universe.


Class Objective



• To gain an understanding of the size and age of the universe and the various components.


Class Objective




• To learn how we know what we know. (this is where the “technology” of the course comes in)


Class Objective




• To learn how we know what we know. (this is where the “technology” of the course comes in)

• The content of this course is really more like astrophysics, and it will involve some standard scientific skills, like interpreting plots and performing numerical calculation.


Class Non-Objective

• This is not a course about horoscopes (astrology) or about stories associated with the constellations (mythology).

• To fulfill an easy distribution requirement. Many students at colleges across the country sign up for astronomy because they think it will be easy (they are usually wrong).


Teaching Philosophy

• You are the primary person responsible for learning the material. I am a facilitator.

• What you can do.• Read the book. (It is a good one.)• Do the exercises. (They can be challenging.)• Come to class. (Participate!)

• Ask questions.• Discuss questions with your peers.• You will learn the material the best if you can explain it to

someone.


Teaching Philosophy

• So…• You read the book. (It is a good one.)• You do the exercises. (They can be

challenging.)• You discuss questions with your peers…


Why come to class?


I>clicker Response System

• Add your number to the class roster as you see your name.

• Practice questions will begin now.


Clicker Practice

What is your favorite color?

A. red

B. yellow

C. green

D. blue

E. purple


Clicker Practice

How many days will you miss class this semester?

(Enter a number 1-5)


Reading Quiz

• Did you read Chapter 0?• Lets find out...


About how many stars can you see at one time from Durango with your naked eye?

A) 800

B) 4000

C) 20,000

D) 100,000

E) 1,000,000


About how many constellations can you see at one time?

A) 22

B) 44

C) 88

D) 144


Magnitude

• Historical Magnitude Scale• Hipparcos/Ptolemy• The brightest stars were “of the first magnitude”• Dimmer stars were second, third, etc.

magnitude.• Dimmest stars were 6th magnitude


How many Stars Can You See?

Magnitude Range Cumulative Stars % Increase Seen-1 -1.50 to -0.51 2 -

0 -0.50 to +0.49 8 400%

1 +0.50 to +1.49 22 275%

2 +1.50 to +2.49 93 423%

3 +2.50 to +3.49 283 304%

4 +3.50 to +4.49 893 316%

5 +4.50 to +5.49 2,822 316%

6 +5.50 to +6.49 8,768 311%

7 +6.50 to +7.49 26,533 303%


Charting the Heavens

The “Obvious” view


Photos


Figure P.1aThe Constellation Orion


Constellations

• There are 88 constellations defined on the celestial sphere.

• Many are historical• There are no “empty” places• Many correspond to asterisms.

• Asterism - a noticeable pattern of stars that makes up part of one or more constellations; not a constellation itself.


Constellations

• The stars in a constellation are not physically close to each other - they just happen to be in the same direction.


Figure P.1bThe Constellation Orion


Figure P.2The Celestial Sphere


Measurements and Units

http://faculty.fortlewis.edu/hakes%5Fc/

http://faculty.fortlewis.edu/hakes_c/


Measurements

• Measurements allow us to compute quantities and solve problems

• Science attempts to describe nature in an objective way through measurements

• Standard Unit (everyone can understand)• System of Units (group of standards)

• Metric System (SI)• British System


Length


Time


Mass

• Mass is the only fundamental unit that is still defined by an artifact - a one kg platinum cylinder.


SI Units

Name of

Unit

Abbreviation Property

Measured

meter m length

kilogram kg mass

second s time

ampere A electric current

kelvin K temperature

mole mol substance amount

candela cd luminous intensity


Dimensional Analysis

• Dimensional Analysis is VERY helpful in problem solving.

• Check your equations with specific units.• Velocity example - how do distance (x),

time (t), and Velocity (V) relate?

V = x/t


Velocity Exercise

• You drive 60 miles to Pagosa Springs at 55 miles per hour. How many hours does this take?


Dimensional Analysis Example - Which equation is correct?

A) velocity = distance * time

B) time = velocity * distance

C) time = distance / velocity

D) time = velocity / distance


Which equation is correct?

A) velocity = distance * time

B) time = velocity * distance

C) time = distance / velocity

D) time = velocity / distance


Velocity Exercise

• The laser travels 9.6m across the room. How many seconds does it take?


Light Travel Time Across the Room (9.6 meters)

A) 2.9x106 sec

B) 2.9x10-6 sec

C) 3.2x10-5 sec

D) 3.2x10-8 sec


Three Minute Paper

• Write 1-3 sentences.• What was the most important thing

you learned today?• What questions do you still have

about today’s topics?

Charles Hakes Fort Lewis College1. Charles Hakes Fort Lewis College2 The View from Earth and Physics...

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