1. Brain Pop The Sun

2. The Sun The closest star to earth. The reason we have life on earth.
Average main sequence star.

3. Sun’s Mass The Sun is 300,000 times Earth’s mass.
The Sun is composed mostly of Hydrogen and some Helium (and ~2% other elements).
The Sun is completely gaseous.
Diameter = 1,300,000 km
The Sun generates energy in its core.
Most massive object in the solar system.
The sun generates energy in its core that radiates outward through the layers.

4. Layers of the Sun Atmosphere: Interior The Photosphere (Surface)
The Chromosphere
The Corona
Interior
Core
Radiation Zone
Convection Zone
There are 2 parts of the sun: Atmosphere and Interior.
The atmosphere consists of the photosphere, chromosphere, and corona.
The Interior of the consists of the core, radiative zone and the convective zone.

5. The Core Fusion of hydrogen to helium Converts mass to energy
E=mc2
600 million tons of hydrogen converted to energy every second
We are going to describe each of the layer and what goes on in them.
Put “Core” in the margin and copy the notes.
E= the amount of energy that can be produced by a certain amout of mass.
M = mass c = speed of light (constant)

6. Step 3: proton combines with p/n pair
Hydrogen
Hydrogen
There are basically 5 steps to hydrogen fusion.
Step 3: proton combines with p/n pair
Step 1: 2 hydrogen atoms fuse
Step 2: One proton changes to a neutron.
Step 5: this results in formation of Helium
Step 4: 2 nuclei fuse

7. Inner Zones-Energy moves through 2 inner zones
Radiative zone
Surrounds core
2,500,000 oC
Energy is transferred through EM waves
Convective Zone
Around radiative zone
Uses convection to transfer heat to surface
Cool gases sink
Warm gases rise
1,000,000 oC

8. Three layers in the uppermost region of solar gases
Sun’s Atmosphere
Three layers in the uppermost region of solar gases

9. Photosphere Appears granular due to convection
“light sphere” because it gives off visible light.
6000 oC
Above the convective zone
This is the layer we see. Gives off the visible light

10. Chromosphere Layer above the photosphere “color sphere” glows red
Temp varies greatly
4, ,000 oC
Occasionally form narrow jets of hot gas
Hot gases can shoot outward to heights of 16,000 km.

11. Corona The outermost layer of the Sun’s atmosphere
Can only be seen during an eclipse
Photosphere too bright
Gives off the solar wind
Charged particles streaming through the corona
Helps keep in charges particles. Some escape through holes in the corona. Solar wind.
Suns magnetic field helps protect not only the sun but the whole solar system.

12. Sun’s Layers - Movie

13. Homework
Do p
Use complete sentences

14. Solar Activity p

15. Sunspots “Dark” regions on the Sun. Usually form in pairs
We are experiencing a solar minimum
“Dark” regions on the Sun.
Actually, cooler regions (lower temp. -> less intense).
Usually form in pairs
Number of spots varies with an 11 year cycle.

16. Sunspots Position and number of sunspots change over time.
The Sun rotates differentially
25.4 days at equator
27.8 days at 45º
11 year cycle of sunspot activity.
2001 – Sunspot maximum (around 100 spots visible).
~5.5 yrs. later – Sunspot minimum (only a few spots visible).

17. The Cause of Sunspots
Different parts of the sun rotate at different speed.
As the Sun rotates, the magnetic field is twisted and causes cooler regions.
Strong magnetic fields slow down convection = cooler areas show up as sunspots.

18. Hot Rising Gas
Magnetic Field
How Sunspots Occur

19. Prominences
Prominences – hot ionized gas trapped in magnetic field lines.
Stretch from one sunspot to another.

20. Solar Flares Sudden outward eruption of electrically charged particles
Last only seconds but give off energy = millions of H bombs
Usually associated with sunspots
May strengthen the solar wind
Can cause interference with radio communication on earth.

21. Auroras Northern/Southern Lights
Auroras
Northern/Southern Lights
Electrically charged particles hit the magnetosphere.

22. Sun’s Activity-Movie

23. Answer questions on page 579
p complete sentences