Chapter 16 Stars, Galaxies, and the Universe

1
Chapter 16Stars, Galaxies, and the Universe

• UEQWhat are the physical properties of the
  Universe?

2
Note Taking Guide

• Page 2 Eqs
• Page 3 Vocabulary
• Page 4 Prediction Activity
• Page 5 Chapter 16 Notes (Set up according to my
  directions)
• Page 6 Page 471 Questions
• Page 7 Internet Activity
• Star book has no page number, keep it in a
  side poket.

3
EQ and Vocabulary

• EQ What are the physical properties of stars?
• Vocabulary
• physical properties, classify, temperature,
  element, astronomer, star, radiate, atmosphere,
  spectrum, spectrograph, continuous spectrum,
  absorption spectrum, constellation,
  apparent magnitude, absolute magnitude,
  luminosity, light year, parallax

4
Vocabulary Definitions

• Physical Properties-any aspect of an object or
  substance that can be measured or observed.
• Classify- arrange in classes or categories
  according to shared qualities or characteristics
• Temperature- the degree or intensity of heat
  present in a substance or object
• Element- a pure chemical substance consisting of
  one type of atom distinguished by its atomic
  number, which is the number of protons in its
  nucleus.
• Astronomer- an expert in or student of astronomy,
  the branch of science that deals with celestial
  object, space, and the physical universe as a
  whole.
• Star- a fixed luminous point in the night sky
  that is a large, remote incandescent body like
  the sun.
• Radiate-emit (energy, esp. light or heat) in the
  form of rays or waves
• Atmosphere- the envelope of gases surrounding the
  earth or another planet
• Constellation- a group of stars forming a
  recognizable pattern that is traditionally named
  after its apparent form or identified with a
  mythological figure. Modern astronomers divide
  the sky into eighty-eight constellations with
  defined boundaries.
• Luminosity-the intrinsic brightness of a
  celestial object (as distinct from its apparent
  brightness diminished by distance).

5
Stars

• Prediction Activity
• Write down the following chapter headings. Look
  through chapter 16 pgs 464-470 and preview the
  chapter. As you preview write under each heading
  write what you think you will learn while reading
  that section.
• Color of Stars
• Composition of Stars
• Classifying Stars
• How Bright is that Star?
• Distance to the Stars

6
Color of Stars

• Color relates to temperature
• Candles burn with yellow or red flames
• Bunsen burners burn with blue flames
• We consider yellow and red to be warm colors
  and blue to be a cool color
• In actuality the yellow and red flame is much
  cooler than the blue flame
• In science red and yellow are cooler than blue
  this relates to the stars, blue stars are much
  hotter than red and yellow ones

7
Color of Stars

• Betelgeuse
• Answer
• Explain how
• Color relates to
• The temperature
• Of stars.
• Rigel

8
Stars Video

• United Streaming Video
• Exploring Space The Universe The Vast Reaches
  of Space 21 minutes

9
Composition of Stars

• Stars of made up of elemental gases
• Inner layers are dense and hot
• Outer layers (stars atmosphere) are less dense
  cooler gases
• Elements in the stars outer layer absorb some of
  the light that radiates from the star
• Elements absorb different wavelengths of light
  which lets us determine what elements make up the
  star

10
Composition of StarsThe colors of light

• A spectrum is the band of colors produced when
  white light passes through a prism
• The spectrum consists of millions of colors
• A spectrograph is used by astronomers to break a
  stars light into a spectrum
• This spectrum gives astronomers information about
  a stars composition and temperature

11
Composition of StarsIdentifying Elements in a
Star

• A spectrograph shows emission lines which are
  lines that are made when certain wavelengths of
  light, or colors are given off by hot gases.
• Each element will only emit a unique set of
  bright emission lines. These are like
  fingerprints for the element.
• Examples

12
Composition of StarsTrapping the light Cosmic
Detective Work

• Elements produce a spectrum when charged by an
  electric current, this spectrum is made up of
  bright emission lines and is called a Continuous
  Spectrum
• A star produces a spectrum containing dark
  emission lines because the stars atmosphere
  absorbs certain colors of light, it is called an
  Absorption Spectrum

Question How does the absorption spectrum
differ from the continuous spectrum?
13
Composition of StarsIdentifying Elements by
Using Dark Lines

• A stars atmosphere absorbs colors of light so
  its spectrum is called an absorption spectrum
• An absorption spectrum is produced when light
  from a hot solid or dense gas passes through a
  less dense, cooler gas.
• Black lines of a stars spectrum represent
  portions that are absorbed by the atmosphere
• The pattern of lines in the absorption spectrum
  show some of the elements in the stars
  atmosphere.
• However, a star is a mixture of gases so sorting
  through the patterns can be puzzling and
  confusing.

Question Explain how astronomers use the
absorption spectrum to identify elements in the
atmospheres of stars.
14
Classifying StarsDifferences in Temperature

• Stars are classified by how hot they are.
• Temperature differences result in color
  differences that can be seen.

Class O- 10 Lacertae Class B- Rigel, Spica,
Regulus, Algol, and Spica Class A- Vega, Sirius
A, Deneb, Altair, and Castor Class F- Procyon,
and Polaris Class G- The Sun, and Capella Class
K- Arcturus, Aldebaran, and Pollux, Class M-
Betelgeuse, Wolf 359, and Antares
15
Stars Video

• United Streaming Video
• Exploring Space The Universe
• 29 minutes

16
Star Book Directions

• You will need to make a book out of construction
  paper and white typing paper
• The cover of the book should be a 11 by 9 piece
  of construction paper folded in half (this is
  exactly ½ of a large piece of construction paper
• Fold four sheets of paper to fill the inside of
  the book
• Number the pages 1-8
• Page 1 should be a table of contents for each
  page in the book
• Page 2-8 should be a class of star per page
  (O,B,A,F,G,K,M)
• Each page needs to have the following
  information Star name, Temperature, Color, Star
  Elements, Picture of the Star

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Classifying StarsClass O

• 10 Lacertae
• Color Blue
• Temp above 30,000
• Elements Helium

18
Classifying StarsClass B

• Spica
• Color Blue-White
• Temp 10,000- 30,000
• Elements He H

Rigel
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