Chapter 4; Lesson 4.1

T.O.C: The Sun is our Local Star

The Sun produces Energy from Hydrogen

• The Sun is the only star in our solar system.

• It is far larger than any of the planets (contains over 99% of the mass of our solar system)

• Consists mostly of hydrogen gas. Energy is produced when the hydrogen turns into helium. • This energy is the source of light & warmth

that make life on Earth possible

Energy flows through the Sun’s layers• Even though it is made of gas, it does have a

structureThe Sun’s Interior:

1. Core- very dense gas. Temps about 27 million degrees F. • Fusion(w.w)- In this temp, hydrogen particles collide to

form helium

2. Radiative Zone- energy from core moves through this thick layer via radiation. Fusion does not occur here

3. Convection Zone-Energy moves via convection. Rising currents of hot gas carry energy towards the Sun’s surface• Convection(w.w)- transfer of energy from place to place

by the motion of heated gas or liquidConvection Lab!!

Energy flows through the Sun’s layersThe Sun’s Outer layers are its atmosphere

The Sun’s Atmosphere:4. Photosphere- A.K.A- the Sun’s surface.

visible light moves out into space from here.

5. Chromosphere- thin middle layer of atmosphere that gives out pinkish light

6. Corona(w.w)- the Sun’s outermost layer. Varies in shape & extends outwards several million miles. • Corona & chromosphere are much hotter than

photosphere. Can only see their light during total eclipse of the Sun

• Create drawing of Sun’s layers in your Notebook. See page 117

• http://www.youtube.com/watch?v=VEYlVxVOmQ8

• http://www.youtube.com/watch?v=GZC7mocf1Q4

• http://www.youtube.com/watch?v=89GJWHYNScE

Features of the Sun• Magnetic fields- twist into different

positions while Sun rotates– Different parts of Sun can rotate different ways

• Sunspots(w.w)- spots on photosphere that are cooler than surrounding areas– Follows patterns that last about 11 yrs after

cycle there may be none– Move across Sun’s surface as it rotates

• Solar flares & prominences– Flares- eruptions of hot gas from Sun’s interior– Prominence- huge loops of glowing gas that

extend into the corona

Features of the Sun continued• Solar wind- electrically charged

particles that flow out in all directions from the corona–Most flowing toward Earth is guided safely

around by Earth’s magnetic field.–When solar wind particles reach Earth’s

upper atmosphere it creates auroras (N./S. lights)

Magnetic storms- can disrupt electric power delivery by causing power surges, interfere with radio communication, damage/destroy orbiting satellites.

4.1 Review Q’s 16 points1. Name the 5 features of the Sun we

discussed and explain each (10 points)2. How does the Sun produce energy? (2

points)3. What causes auroras at the North/South

poles? (2 points)4. Why is the core the only layer of the Sun

hot enough to produce energy? (2 points)