Friday 9-27-13

1. WU: What is the strongest evidence for Big Bang Theory? Check Universe lab Star life Cycle Notes A Stars life WS Friday 9-27-13

2. Scientific Method Plan Revisions 1. Fix any problems with your plan. 2.  Show your parents the original and your revised. 3. Have your parents sign the original and the new plan at the end of each document after they have:      -checked your revisions      -read, ok’d, and initialed the safety concerns.     -agreed upon any cost or time required of them for your project 4.  complete science fair checklist 1A

3. Proposal Revisions – Due Monday 9/30 • Fix any mistakes • Add in-text citations to your revisions • Not sure how to add in-text citations…go to the library’s website: • In-text citations: • Original Proposal will be turned in with your revisions on Monday, 9/30. • **Parent signature on the original and new proposal – see the slip of paper • Staple slip of paper and rubric to your proposal • Student Checklist 1A & Parent Approval 1B forms

4. Sparkling Dots

5. LIFE CYCLE OF A STAR All of the little bright spots are stars forming out of the gas. It is an area of dust and gas in space where stars are “born”. This is a nebula.

6. Classified by their: Composition Brightness Temperature Mass Life Cycle Stars

7. Composition Made up of different elements in the form of gasses When viewed through a spectroscope the specific gasses can be identified through an absorption spectrum which is a continuous spectrum with dark lines where less light gets through. Stars

8. Composition Stars Color spectrums on notes! http://hrw.com

9. Brightness (Luminosity) Apparent Magnitude – how bright a star looks from Earth Absolute Magnitude – how bright a star actually is (How bright the star would appear to the human eye if it were at a distance of 10 parsecs from the earth) Stars Is this apparent or absolute magnitude?

10. Temperature Determined by the color of a star Classified by the following letter categories (O, B, A, F, G, K, M) Stars http://hrw.com

11. Fill out planner WU: -What 5 properties are Stars classified by? -What is the difference between apparent and absolute magnitude? 3. Finish Notes 4. A Stars Life WS Monday 10-1-12

12. Mass Sun like stars Up to 1.5 times the mass of the sun Huge Stars From 1.5 to 3 times the mass of the sun Giant Stars Over 3 times the mass of the sun Stars http://hrw.com

13. Life Cycle Stars http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle/

14. Life Cycle Of A Star Stars change and evolve in a predictable pattern over time. The path a star takes over its lifetime depends on the star’s MASS.

15. The Horsehead Nebula The Nursery All stars begin their life in a NEBULA. A nebula is a gigantic cloud of dust, gas, and plasma in space. If there is enough matter in the nebula, gravity will start to pull everything together into a PROTOSTAR. A protostar is an infant star…the equivalent of a newborn baby.

16. Average Stars Average stars spend most of their lives as boring, normal MAIN SEQUENCE stars. Our sun is a great example. It is about 4.5 billion years old. Average stars can live up to 10 billion years before they begin to die out. In a nuclear reaction the # of protons in the nucleus changes creating a new & different atom H + H  He They create heat and energy through the process of nuclear fusion.

17. Average Stars As an average, main sequence star gets older and larger, it becomes a RED GIANT. This means the end is getting near. Red giants are incredibly massive and bright, but are relatively cool compared to younger stars…the fire is going out. When our sun becomes a red giant, Earth will look like Mercury.

18. Sirius A and B Average Stars Eventually, the fuel for the nuclear reactions at the heart of the star runs out. Average red giants simply collapse in a “puff” of gas. What’s left behind is a small core of carbon and oxygen called a WHITE DWARF. A small amount of heat is still produced, like an oven that’s still warm after its been turned off.

19. Massive Stars Massive stars are much larger and brighter than their smaller relatives. Massive stars will spend much of their lives blueish-white because they are so hot. Eventually, they will make it to the RED SUPERGIANT stage as they age and cool. This is just like a red giant except bigger and hotter. A LOT bigger and hotter. The constellation Orion has two red supergiants in it.

20. Massive Stars Red supergiants don’t “puff” away when they get older like their smaller relatives…they explode. This SUPERNOVA ejects gas, radiation and a blast wave far into space. It will light up the skies for weeks or months. A supernova will briefly outshine its own galaxy when it explodes.

21. Massive Stars NEUTRON STARS are one of the possible leftovers after a supernova. In a neutron star, all the leftover matter from the massive star is crushed and condensed down to a core smaller than the Earth. They are extremely dense and have tremendous amounts of gravity. Neutron stars are also known as PULSARS because of the pulses of gamma rays they give off.

22. Massive Stars The last option for a massive star is the most frightening. The largest of the massive stars have so much mass that after a supernova, the leftover material collapses in on itself to form a BLACK HOLE. There is so much gravity created by the density of the leftover material that a hole in space is ripped open. Not even visible light can escape.

23. Stars http://hrw.com The Hertzsprung Russell Diagram (H-R) is a graph showing the relationship between a star’s surface temperature and its absolute magnitude Brightest Red Supergiants Main sequence Dimmest Cool Hot

24. H-R Diagram in Notes • Color Code Each Spectral Type on HR Diagram

26. StarsIllustrating the relationship between temperature and brightness http://hrw.com

27. Single most important determiner of a stars life cycle is it’s MASS High Mass Low Mass Life Cycle Of A Star http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle/

28. StarsIllustrating the relationship between mass and star life time http://hrw.com

29. Stars Illustrating the relationship between mass and brightness http://hrw.com