1. What do all stars begin their life as ?
Physical Science
10/23
Bell Work:
What do all stars begin their life as ?
What kind of star will this form?
What does “proto” mean?
Agenda:
Lives of Stars
Outer Space WS
Learning Target:
I can descrbe the life cycle of a star.
I can explain how stars differ in size, temperature, and color.
Homework/Important Dates:
Book Notes, Vocab. And Outer Space WS due Thursday 10/26
Unit 6 Test on 10/31

2. Physical Science Notes
Lives of Stars

3. The Life of Stars Stars start their lives as parts of nebulas.
Nebulas are large clouds of gas and dust spread out over a massive area.
In the densest part of nebula, gravity pulls the gas and dust so closely together that nuclear fusion starts.
The next stage is a protostar, which is the earliest stage of the star’s life.

4. The Life of Stars The mass of the star determine its lifespan.
The smaller the star, the longer the life.
The size of the star also determines what path it will take as it goes through its cycle.
High mass protostars take a different path than lower mass protostars.

5. The Life of Stars
The next stage in the life of a star is the main sequence.
This is the stage our sun is in.
Higher mass stars tend to burn hotter.
Low mass stars expand into red giants, while high mass stars expand into supergiants.
These are low temperature stars that burn slowly because they have used all their hydrogen.

6. The Life of Stars
If it is a low mass star, the next stage after the red giant is the planetary nebula.
The star expands and the parts drift apart, forming a nebula.
A high mass star will go supernova, suddenly exploding and releasing massive amounts of energy.

7. The Life of Stars
Low mass stars leave their cores behind when they turn into planetary nebulas.
The core cools and compresses and turns into a white dwarf.
White dwarfs have about the same mass as the sun, but they have the size of Earth.
Nuclear fusion no longer takes place, but the star continues to shine with leftover energy.

8. The Life of Stars High mass stars have two paths.
Neutron stars are the left over cores of the supergiant.
They are much like white dwarfs, but a million times denser.
Spinning neutron stars are called pulsars.
Pulsars emit radiation in predictable patterns.

9. The Life of Stars The other path is a black hole.
Only the densest stars become black holes.
Nothing can escape the gravity of a black hole, not even light.
Scientists can only detect black holes based on how they affect other stellar bodies.

10. Hertzsprung-Russell Diagrams
The Hertzsprung-Russell diagram (HR diagram) is a way for scientists to classify stars and understand how they change over time.
The x-axis represents temperature.
The y-axis represents absolute brightness.
Bright
Dim
Hot
Cooler

11. Hertzsprung-Russell Diagrams
More than 90% of stars are in the main sequence.
Stars in the main sequence have their brightness increase in proportion to their temperature.
Stars that have started to die tend to stray off the main sequence.
These stars have used up all the hydrogen and started to expand, or are white dwarfs that have already passed through that phase.

12. Hertzsprung-Russell Diagrams
Why are the giants so bright, even though they are not so hot?
The brightness of a star is based on both its temperature and how big it is.
Giants are much bigger than main sequence stars, so they have a much larger surface area to emit light.

13. Describe all the stages of a high-mass star’s life. Physical Science
Bell Work:
Describe all the stages of a high-mass star’s life.
Physical Science
10/24
Agenda:
HR Diagram WS
The Life Cycle of Stars WS
Learning Target:
I can describe the life cycle of a star.
I can explain how stars differ in size, temperature , and color.
Homework/Important Dates:
Book Notes, Vocab. And Outer Space WS due Thursday 10/26
Unit 6 Test on 10/31

15. Physical Science 10/25 Research Project
Bell Work:
Describe all the stages of a low-mass star’s life.
Physical Science
10/25
Agenda:
Research Project
Learning Target:
I can research aa astronomy topic and create and deliver an informative presentation about my topic.
Homework/Important Dates:
Book Notes, Vocab. And Outer Space WS due Thursday 10/26
Unit 6 Test on Tuesday 10/31

16. What is a planetary nebula?
Physical Science
10/26
Bell Work:
What is a planetary nebula?
What is a white dwarf?
What are neutron stars?
What are black holes?
Agenda:
Review Quiz
Review Outer Space WS & Life Cycle of a Star
Learning Target:
I can descrbe the life cycle of a star.
I can explain how stars differ in size, temperature , and color.
Homework/Important Dates:
Unit 6 Test on Tuesday 10/31
Friday Packet:
Bell Work
Notes
Book Notes / Vocab.
Outer Space
HR Diagram
Life Cycle of Stars

18. Diagram the life of either a low or high mass star.
Physical Science
10/27
Bell Work:
Diagram the life of either a low or high mass star.
Agenda:
Quiz
Unit Test Study Guide
Friday Weekly Assignments: Bell Work
Notes
Book Notes / Vocab.
Outer Space
HR Diagram
Life Cycle of Stars
Homework/Important Dates:
Unit 6 Test on Tuesday 5/16

19. Make a 6x6 BINGO card (if you want a chance to win)
You may use the numbers instead of the words (this time).
You may have 1 free spot.
The numbers must not be written in pencil.
EM Radiation