1. Chapter 30
Stars and Galaxies

2. SOAR Chapter 30 Objective 1 Describe our sun and explain how it works.
Standard
1d. Students know the evidence indicating that the planets are much closer to the Earth than the stars.
2d. Students know that the stars differ in their life cycles and that visual, radio, and Xray telescopes may be used observe them.
1e.Students know that our sun is a typical star and is powered by nuclear reactions.
Objective 1
Describe our sun and explain how it works.
Objective 2
Describe the composition of stars.
Objective 3
Describe how astronomers measure distances to stars.
Objective 4
Describe star formation and evolution.
Objective 5
Identify the 3 types of galaxies.
Assessment and Review
Daily bellwork, science starters,
Chapter 30 Test

3. Key Terms
Create a flashcard for each of the following (they begin on page775):
Star
Light-year
Parallax
Main sequence
Giant
White dwarf
Nova
Neutron star
Pulsar
Black hole

4. Our Sun A typical, average star
75% of the sun is Hydrogen, the rest is Helium
Nuclear Fusion= 2 Hydrogen atoms fusing to become one Helium atom.
Nuclear Fusion creates a tremendous amount of energy

5. Our Sun Brainpop

6. Stars
All stars are balls of gases that give off extreme amounts of energy due to Nuclear Fusion
Stars are made of mostly Hydrogen and Helium with some Carbon, Oxygen, Nitrogen
The temperature of a star is indicated by its color.

7. Distances to Stars Distances between stars are measured in light years
For closer stars Scientists use PARALLAX to determine its distance from Earth.
PARALLAX=the apparent shift of a star’s position when viewed from different positions.
One star might appear in the left of the sky in January but on the right of the sky in June…

9. Parallax Clip

10. Main Sequence Stars Classifying Stars
Scientists use radio, X-ray, and Visual telescopes to classify stars
H-R Diagram is used to organize the stars by Luminosity and Temperature
Main Sequence Stars

11. Star Life Cycle Brain Pop

12. Life Cycle of a Star All stars begin as a cloud of dust and gas
Nebula
All stars begin as a cloud of dust and gas
Protostar
Gravity pulls the nebula together and when temps increase to 10 million degrees, nuclear fusion begins and a star is born
Main-Sequence
Longest stage of a stars life
Energy continues to generate by way of nuclear fusion

13. If the star was massive, they become SUPERGIANTS
Giant Stars
As he hydrogen atoms deplete the star contracts
Then the core becomes hotter, causing the star to expand larger than before
As they cool they glow red…RED GIANT
Super Giants
If the star was massive, they become SUPERGIANTS
Final Stages
Planetary Nebula: The gases drift away leaving a nebula
White Dwarf: After the gases of the planetary nebula drift away the remaining matter collapses and gravity pulls it together creating a WHITE DWARF..they shine for billions of years until cool
Black Dwarf: When the white dwarf is completely cool and no longer gives of light—many scientists do no believe these exist yet

14. Novas Supernova Neutron Stars
In a binary system, if a white dwarf revolves around a red giant an explosion can occur= NOVA
Supernova
Massive stars become Red Supergiants…the gravity is so great hat fusion of heavier elements (Carbon) begins until all the fuel is gone
With the fuel gone the core collapses and the star explodes
Neutron Stars
After a supernova the leftover core may become a very dense ball of neutrons
Neutron Stars rotate very rapidly

15. Pulsars Black Holes Neutron stars that emit a beam of radio waves
Like a lighthouse
Black Holes
Remaining core after a supernova contracts under its own gravity but is SO MASSIVE that is leaves a black hole
Gravity is so great that not even light can escape it
Black Holes cannot be seen but their effect on their companion stars can be seen (the second star orbits around seemingly nothing)

16. Life Cycle of a Star

17. INTERACTIVE Comic Strip/Cartoon of our star’s (the sun) life cycle
Picture and text for each segment (use p to help)
Nebula
Protostar
Main-Sequence
Red Giant
Planetary Nebula
White Dwarf

18. Types of Galaxies
Galaxies account for most of the visible mass in the universe.
Spiral
Elliptical
Irregular

19. Assessment/InteractiveOR
Complete the Maps in Action Activity on page 804.
Left Hand side of your notebook
Do NOT copy the question, but answer in complete sentences
Read the Science and Tech. article on page 805
Answer question 1
Write a half-page summary