1. Life of a Star HOW DO STARS FORM?

2. Video Clip https://school.bighistoryproject.com/pages/console/#units/{9DE7FB97-F2B4-4F5B-B669- 2B7F65270DFF} “A Big History of Everything” Answer the question sheet as we go…

3. What force(s) did the Big Bang create? Four Fundamental Forces: 1. Gravity 2. Electromagnetism 3. Strong Nuclear Force 4. Weak Nuclear Force

5. Why is the cooling of the universe significant? As the universe cools, conditions are created to INCREASE COMPLEXITY. More complex elements are created.

6. Why are atoms of hydrogen and helium drawn together into clouds? Hydrogen and Helium are pulled together by GRAVITY. Gravity is acting on these clouds, creating the opportunity for nuclear fusion.

7. What happens as clouds get larger? Stars light up. Before stars, there was no light in the universe.

8. How did stars change the universe? The first generation of stars light up the universe, but their fuel runs low and the burn out. With the death of the first generation of stars, complexity is born.

9. Anticipatory Set Put the pictures in order from EARLIEST to LATEST stage of star formation. YOU HAVE 4 MINUTES Discuss your thoughts with your group as you go.

10. Video Clip https://school.bighistoryproject.com/pages/console/#units/{9DE7FB97-F2B4-4F5B-B669- 2B7F65270DFF} “How Stars Formed” Continue answering questions on the provided sheet as we go…

11. Which elements were a prominent part of the early universe? 75% of stars are made of Hydrogen 25% of stars are made of Helium Less than 1% are made of Beryllium, Lithium, and Boron

12. What conditions influenced increased complexity in the universe? As the universe expands, it cools, creating conditions to increase complexity…

13. What is GRAVITY’S ROLE? GRAVITY is one of the four fundamental forces. *It is defined as the fundamental force of attraction between bodies of mass. (The other fundamental forces are ELECTROMAGNETISM, WEAK INTERACTION AND STRONG INTERACTION).

14. How are stars formed? Stars are formed within clouds of dust. Gravity pulls particles of dust and gas together… As the cloud collapses, a dense hot core forms and begins gathering dust and gas. NOT ALL OF THE DUST AND GAS ends up as part of the star – the remaining become planets, moons, and asteroids.

15. What conditions triggered star formation? As clouds became more dense, gravity increases. At the center of these dense clouds, temperature increases because atoms are colliding and banging against each other. At 10 million degrees, fusion happens. Atoms are held together by strong nuclear force. When fusion occurs, stars light up.

16. Why do stars get together as galaxies? We live in the Milky Way. Gravity gathers galaxies together to create star clusters. Gravity can hold clusters together to create super clusters. Gravity is too weak to hold super clusters together. (This is where we can observe the expansion of the Universe)

17. Let’s Review the Warm Up On your warm up page, you were asked to put the PICTURES in order from FIRST to LAST. Let’s take a look…

18. Step 1: “C” - Protostar Protostar – A star that has not yet reached the fusion stage. It grows by accretion, acquiring mass from surrounding interstellar dust and gas. How can we summarize this?

19. Step 2: “D” - Star Star – The star shines as nuclear reactions inside produce light and heat. The vast majority of stars in the Universe are in this stage (including our star). How can we summarize this?

20. Step 3: “B” – Red Giant Red Giant – The star expands and glows red as it cools, eventually blasting away its outer layer. How can we summarize this?

21. Step 4: “A” - Supernova Supernova Remnant – The result of an explosion of a star, consists of material ejected from the explosion. Only the most massive stars become supernovas. How can we summarize this?

22. Answer the EQ Let’s complete the “Question Exploration Guide” together. You will ANSWER your EQ and make real world connections INDEPENDENTLY.