1. Chapter 29.1 Structure of the Sun
Std 1e: Students know the Sun is a typical star and is powered by nuclear reactions, primarily the fusion of hydrogen to form helium.
Objective 1: Explain how the sun converts matter into energy in its core
Objective 2: Compare the radiative and convective zones of the sun
Objective 3: Describe the 3 layers of the sun’s atmosphere

2. The Sun’s Energy 300,000x larger than Earth
Spectrograph – a device used to break up the sun’s light into a spectrum
Used to determine the amount of elements in the Sun

3. Composition of the Sun
Both Hydrogen and Helium occur in the sun
75% of sun’s mass is hydrogen
Hydrogen and helium together make up 99% of the sun’s mass

4. Nuclear Fusion
Nuclear fusion - the process by which nuclei of small atoms combine to form a new more massive nucleus
Fusion releases huge amounts of energy and has 3 steps: *each step releases energy

5. Step 1) Two hydrogen nuclei (or protons) collide and fuse.
One proton will become a neutron (release of positron)
It is a proton-neutron pair

6. Step 2) Another proton combines w/ the pair making a 2 proton 1 neutron nucleus

7. Step 3) Two of these nuclei (2 pro 1 neu) collide and fuse.
2 protons are released.
The remaining 2 protons and 2 neutrons fuse forming a helium nucleus

8. The Final Product
Nuclear fusion of 2 hydrogen nuclei combines to produce a helium nucleus
The helium nucleus is only 0.7% mass of the hydrogen nucleus from which it formed
The lost mass is converted into energy, which causes the sun to shine and it’s high temperature

9. Mass Changing in Energy
The sun’s energy comes from nuclear fusion
The mass lost during fusion becomes energy
Subatomic particles are released = Neutrinos

10. Einstein’s equation (E=mc2) can be used to calculate how mass (or matter) can be converted into energy
E = energy produced
m = mass or amount of matter
c = speed of light (3,000,000km/s)
Astronomers used this equation to explain the huge quantities of energy produced by the sun

11. Objective 1: Explain how the sun converts matter into energy in its core
What provides the sun with its energy?
Nuclear fusion
What 2 elements make up the sun’s mass?
Hydrogen and helium
In the equations E = mc2, what does the c represent?
Speed of light (3,000,000 km/s)

12. The Sun’s Interior Has 3 parts: 1) The Core 2) The Radiative Zone
3) The Convection Zone

13. 1] The Core The center of the sun, it’s 25% of sun’s diameter
Temp = 15,000,000 °C –
Converts matter into energy!

14. 2] The Radiative Zone The layer surrounding the core
Temps range from 2,000,000-7,000,000 °C.
Energy moves outward in the form of electromagnetic waves, or radiation

15. 3] The Convection Zone Surrounding the Radiative Zone
About 2,000,000 °C.
Energy in this zone moves by convection
As gases move outward from this zone it losses energy, becomes more dense and sinks
Therefore, energy is transferred

16. Objective 2: Compare the radiative and convective zones of the sun
What are the 3 parts of the sun’s interior?
Core, convection zone, and radiative zone
What is the temperature of the core?
15,000,000 °C
How does energy move in the radiative zone?
Electromagnetic waves (radiation)
What surrounds the radiative zone?
Convection zone

17. The Sun’s Atmosphere
Surrounding the Convection Zone is the sun’s atmosphere (the uppermost region of solar gases)
The 3 layers are:
1) Photosphere
2) Chromosphere
3) Corona

18. 1] The Photosphere The innermost layer
Made of gases that have risen from the convection zone
Much of the energy given off is in the form of visible light, this light is seen from Earth

19. 2] Chromosphere (above the photosphere)
A thin layer of gases
From 4,000-50,000 °C.
The gases move away from the photosphere forming narrow jets of hot gas that shoot outward

20. 3] The Corona (outermost layer of the atmosphere)
Solar Wind - has a strong magnetic field, electrons and electrically charged particles stream out into space
*The chromosphere and the corona can only be seen from Earth during a solar eclipse

21. Objective 3: Describe the 3 layers of the sun’s atmosphere
What are the 3 layers of the atmosphere?
Photosphere, chromosphere and corona
What is the innermost layer?
Photosphere
What is the layer above the photosphere?
Chromosphere
What has a strong electromagnetic field and electrically charged particles stream into space?
Solar winds