1. The sun gives off tremendous amounts of energy
The sun gives off tremendous amounts of energy. Plants on Earth use sunlight directly in ______________.

2. Energy From the Sun
How does the sun produce energy?
The sun’s energy is produced in its central region by the fusion of hydrogen nuclei into helium nuclei.

3. Hydrogen nuclei collide to form helium-3
Energy From the Sun
_____________ within the sun’s central region converts mass into energy. The green particles in the diagram are protons, and the purple particles are neutrons.
Hydrogen nuclei collide to form helium-3
Gamma ray

4. Energy From the Sun
Nuclear fusion within the sun’s central region converts _____________. The green particles in the diagram are protons, and the purple particles are neutrons.
Hydrogen nuclei collide to form helium-3
Two helium-3 nuclei collide.
Gamma ray

5. Energy From the Sun
Nuclear fusion within the sun’s central region converts mass into energy. The green particles in the diagram are _____________, and the purple particles are _____________. Describe another way of explaining this?
Hydrogen nuclei collide to form helium-3
Two helium-3 nuclei collide.
Helium-4 and hydrogen nuclei form.
Gamma ray

6. Forces in Balance
Why does the sun remain stable over time?
The sun remains stable because the inward pull of gravity balances the outward push of thermal pressure from nuclear fusion.

7. Forces in Balance
_____________ and the outward thermal pressure from nuclear fusion are balanced throughout the sun.
Hypothesis why this is?

8. The Sun’s Interior
What is the structure of the sun?
The sun’s interior consists of the core, the radiation zone, and the convection zone.

9. The Sun’s Interior The sun has an interior and an _____________.
Relate this to something else?
Convection zone (about 200,000 km thick)
Prominence
Radiation zone (about 300,000 km thick)
Chromosphere (about 1500 km thick)
Corona (extending millions of km into space)
Core (about 400,000 km in diameter)
Photosphere (visible surface)
Solar flare
Sunspot (cool region)
Granulated surface (caused by convection)

10. The Sun’s Atmosphere
What is the structure of the sun?
The sun’s atmosphere consists of three layers: the photosphere, the chromosphere, and the corona.

11. The Sun’s Atmosphere
The _____________ can only be seen from Earth during a total solar eclipse or when viewed with a special telescope.
Describe in picture form why we can’t see the corona everyday.

12. Features of the Sun’s Atmosphere
What are some features of the sun’s atmosphere?
Features of the sun’s atmosphere include sunspots, prominences, and solar flares.

13. Features of the Sun’s Atmosphere
_____________ are relatively cool areas on the sun’s surface.

14. Features of the Sun’s Atmosphere
This prominence forms a huge twirling loop connecting sunspot regions.

15. Features of the Sun’s Atmosphere
This _____________ forms a huge twirling loop connecting sunspot regions.
A _____________erupts on the edge of the sun.

16. What is the source of the sun’s energy?
Assessment Questions
What is the source of the sun’s energy?
The friction between its molecules gives off thermal energy.
The conversion of potential energy into thermal energy as gravity pulls the sun into its own core.
Combustion of hydrogen gas on the sun’s surface.
Fusion of hydrogen nuclei into helium nuclei.

17. Assessment Questions
The sun has remained stable for billions of years because there is a balance between
gravity and the tendency of hydrogen and helium to rise.
gravity and thermal pressure.
thermal pressure and the repulsion between nuclei.
the amount of energy it absorbs and the amount of energy it produces.

18. Convection currents in the sun’s convection zone carry energy from
Assessment Questions
Convection currents in the sun’s convection zone carry energy from
the core to the photosphere.
the radiation zone to the photosphere.
the core to the radiation zone.
the photosphere to the corona.