Bell Ringer The outer layer of the Sun’s atmosphere is actually hotter than the interior of the Sun. Explain why you believe this is so.

THE SUN (SOL) (Page 45) https://www.youtube.com/watch?v=2U3ucaVzRqQ

Essential Question: *What are the unique properties of the sun?

*The Sun (A star) - A giant ball of glowing gases -- 74% hydrogen, 25% helium, 1% other gases

*The sun’s structure consists of two parts – interior and atmosphere.

Part 1 -Structure of the Sun (Interior)

Core – center layer *energy is produced here through a process called fusion

Temperature reaches 27,000⁰ F (15,000⁰ C) *Fusion – intense pressure, friction, and heat causes the hydrogen atoms to combine (fuse) together, converting them to helium atoms (2 H → 1 He) Temperature reaches 27,000⁰ F (15,000⁰ C) https://www.youtube.com/watch?v=W1ZQ4JBv3-Y

Radiative Zone where the energy radiates away from the core toward the Sun’s surface

Convective Zone where the energy is moved to the Sun’s surface by convection currents

Structure of the Sun (Atmosphere)

Structure of the Sun (Atmosphere) Photosphere - the visible surface of the sun *approximately 300 miles thick *temperature about 10,000⁰ F (5,500⁰ C) *the light we see takes 8 minutes to reach the Earth

Chromosphere - middle layer of sun’s atmosphere

Chromosphere *about 1,200 miles thick *visible only during a total solar eclipse as a reddish glow

Corona - outer layer of sun’s atmosphere

Corona *The temperature here reaches over 3,500,000⁰ F *emits (sends out) the electro-magnetic radiation *Visible only during a total solar eclipse as white plumes

Corona Chromosphere Photosphere Convective Zone Radiative Zone Core

Bell Ringer If the Sun is so hot that we can’t directly observe it, how are scientists able to determine how hot it is?

THE SUN (Page 46) https://www.youtube.com/watch?v=2U3ucaVzRqQ

Part 2 – Solar Activity

Essential Questions: *How does the sun rotate differently than the planets? *How do events on the sun affect events on the Earth?

*Differential Rotation – different parts of the Sun rotate at different speeds (faster at the equator, slower toward the poles) https://www.youtube.com/watch?v=zUk2otvVoVA *the sun is a ball of gases, not solid like the Earth

Prominence – giant bursts of gases looping out from the sun *can last from several hours to a day *many Earths could fit inside one https://www.youtube.com/watch?v=GrnGi-q6iWc

Solar Flare - an explosive burst of energy from the sun *appears as very bright spots on the photosphere *Similar to a volcanic eruption on Earth

Sunspots - dark areas on the sun’s surface *cooler regions of the photosphere caused by a change in the sun’s magnetic field

Solar wind - a steady stream of charged particles emitted from the sun EARTH *travels about 1,000,000 mph throughout the SS

*The Earth is protected by its magnetic field

*How does solar activity affect conditions on Earth? *Higher than normal bursts of radiation can affect the health of humans

*How does solar activity affect conditions on Earth? *Extreme solar flares and the solar wind can affect satellites, astronauts, GPS systems, jet airplanes, and electrical systems and devices.

*How do we know what we know about the Sun? https://www.youtube.com/watch?v=qLB5ma2Yz1I

Conclusion Using a Venn Diagram, Compare and Contrast The Sun and The Earth