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Solar System is born!. Chapter 15.1 (pages 394-397). Review from Yesterday:. Gravity : What two things effect gravity? Mass and weight: What are they? How are they measured? What are their units? How are they all connected?. Key concepts:.
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Solar System is born! Chapter 15.1 (pages 394-397)
Review from Yesterday: • Gravity: • What two things effect gravity? • Mass and weight: • What are they? • How are they measured? • What are their units? • How are they all connected?
Key concepts: • Explain the relationship between gravity and pressure in a nebula • Describe how the solar system formed
Key Vocabulary: • Nebula • Solar Nebula
Solar Nebulas: The universe…how did it all begin? Remember these terms! • Where does the materials come from that make up our solar systems??? • Clouds in the universe called nebulas • Nebulas: clouds that are mixtures of gases (hydrogen and helium) and dust made of elements • Review time: • Element • Mixture
Formation of planets and stars? Gravity begins the process… • Two forces that interact in nebulas: • GRAVITY • PRESSURE • Gravity holds the particles of matter in a nebula together • a lot of space between matter in nebulas, so the gravitational force is just enough to keep the nebula from drifting apart
Formation of planets and stars? • Why don’t nebulas collapse due to gravity? • Temperaturecauses the particle to move around (temperature is low = little movement, etc.) • When the particles collide due to movement, the particles move away due to PRESSURE • Pressurekeeps the nebula from collapsing on itself
Solar system formation: How does it form? How long does it take? Why is gravity and pressure so important? • From Planetesimals to Planets • As bits of dust circled the center of the solar nebula, some collided and stuck together to form golf ball–sized bodies. • These bodies eventually drifted into the solar nebula, where further collisions caused them to grow to kilometer-wide bodies. • As more collisions happened, some of these bodies grew to hundreds of kilometers wide. • The largest of these bodies are called planetesimals, or small planets.
Formation of planets and stars? The Birth of a Star • As the planets were forming, other matter in the solar nebula was traveling toward the center. • The center became so dense and hot that hydrogen atoms began to fuse, or join, to form helium. • Fusion released huge of energy and created enough outward pressure to balance the inward pull of gravity. • When the gas stopped collapsing, our sun was born and the new solar system was complete!
Review: • The solar system formed out of a vast cloud of gas and dust called the nebula. • Gravity and pressure were balanced until something upset the balance. Then, the nebula began to collapse. • Collapse of the solar nebula caused heating at the center, while planetesimals formed in surrounding space. • The central mass of the nebula became the sun. Planets formed from the surrounding materials.
Homework: • Workbook: Chapter 15.1- • Pages 190-192`