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 __________________.

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

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 _____________________.

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 ______________________.

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. https://www.youtube.com/watch?v=KqXtwAZFfUQ

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. https://www.youtube.com/watch?v=ncphh8FW UUE

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.