1. The Sun
The Sun is a ______, just like the thousands you can see in the night sky. The vast majority of stars in our galaxy host their own __________________.

2. How the sun was formed (I)
During the formation of the Solar System, ________________collapses and contracts, compressing gases.
Temperature of the _______________ increases
Temperature reaches about 10 million °C.
Nuclear Fusion begins
Nuclear Fusion:
_____________ nuclei combine to form _____________ nuclei.
Requires an enormous amount of _____________ and ____________________.
Conditions only exist in the cores of stars (so far)
Not a chemical or physical reaction – it is a nuclear reaction

3. How the sun was formed (II)
_____________ builds up in Protostar’s core.
Pressure and temperature continues to increase, forcing matter outwards.
__________ pulls matter towards the core.
When gravity and pressure are ___________, STAR!
Fun Facts!
Solar astronomers know that the Sun can undergo fusion for a total of 10 billion years. Therefore, it is ___________________.
One helium atom has a larger ___________ than two hydrogen atoms, so as nuclear fusion occurs, the Sun ______________. Solar astronomers estimate that it is _______ larger today than it was when it was a _____________________.

4. Features of the Sun(I)
Photosphere: the _____________ layer of the sun.
Several thousand kilometers deep.
Sunspots: areas of strong ____________________.
Occur when charged particles disturb the photosphere
Photosphere: 6000°C Sunspot: 4500°C
Days for Sunspot Cycles to complete:
North & South Poles: 35 days Equator: 27 days
Therefore, Sun ____________________ and rotates ____________________ at its equator than at poles. It does not rotate like a solid body like ______________________.

5. Features of the Sun(II)
Solar Flares:
Occur where there are complex groups of sunspots
Magnetic fields explosively eject intense streams (_______________________) of charge particles into space.
If solar wind hits Earth:
Solar Storm: disrupt telecommunications, cause large-scale power blackouts, harm astronauts, and damage electronic equipment abroad spacecraft.
Auroras: shimmering curtains of green and/or red light in Earth’s polar regions.
Results when high-energy charged particles are carried past Earth’s magnetic field, generating electric currents. Electric currents charge gases in upper atmosphere, producing light.

7. Importance of the Sun Needed for all life on Earth
Provides us with food (starting with _____________________________)
Provides us with shelter (________________)
Powers winds
Powers ocean currents
Drives all weather
Watch “Secrets of the Sun” by PBS and answer the questions on the corresponding worksheet.
UUE

8. Homework Finish the film and worksheet Page 336 #4 Page 338 #5, 6, 8
Page 340 #1, 2 (read page 339), 3-5, 8, 9.