J. Nguyen – Physical Science Notes Points Name __________________________________ Period _______...

J. Nguyen – Physical Science

Notes Points

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J. Nguyen – Physical Science

Chapter 29 Standards

1a. Students know how the differences and similarities among the sun, the terrestrial planets, and the gas planets may have been established during the formation of the solar system.

1e. Students know the sun is a typical star and is powered by nuclear reactions, primarily the fusion of hydrogen to form helium.

J. Nguyen – Physical Science

Chapter 29 – The Sun

J. Nguyen – Physical Science

I. 29.1 – STRUCTURE OF THE SUN

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A. Introduction to the Sun1. The sun is a star which is a ball of gases that

gives off (produces) a tremendous amount of energy.

2. The sun is the largest object in the solar system.

3. It has 333,000 times the mass of Earth.

4. The sun contains more than 99% of the mass in the solar system.

5. Composition very similar to the gas planets.

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B. Scientists study the sun.1. Scientists use a variety of instruments to study the

sun such as spectrographs, telescopes, instruments on space crafts and satellites etc.

2. Spectroscopy is a technique of using spectral lines to identify the composition, temperature or density of the sun and other distant objects.

3. Dark lines that form in the spectra show what elements are present in the gases of the star and act as a “fingerprint” for each element.

Sun’s Spectra – dark lines are the sun’s elements

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C. Composition of the Sun1. Two most abundant elements of the sun’s mass are

hydrogen and helium.

a. Both hydrogen and helium make up 99% of the sun’s mass.

b. Hydrogen alone makes up 75% of the sun’s mass.

c. Hydrogen’s nucleus contains one proton and one neutron.

d. Helium’s nucleus contains two protons and two neutrons.

2. Other chemical elements are present in small amounts.

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D. Sun’s Energy1. The sun’s tremendous heat and light make it

appear so bright.

2. Nuclear fusion releases huge amounts of energy and produces most of the sun’s energy.

a. Nuclear fusion is the process of combining nuclei of small atoms to form more-massive nuclei.

b. This process takes place in the sun’s core.

c. Nuclei of hydrogen atoms are the primary fuel for the sun’s fusion.

d. Process changes hydrogen into helium.

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E. Three Steps of Nuclear Fusion1. Two hydrogen nuclei (protons) collide and

fuse together. One proton becomes a neutron resulting in a proton-neutron pair.

2. A third hydrogen proton combines with the proton-neutron pair. This results in a nucleus made of three subatomic particles: two protons and one neutron.

3. Two nuclei, each made up of two protons and one neutron, will eventually collide and fuse together. After the fusion, two protons are released.

a. The remaining two protons and two neutrons are fused together and results in helium which contains two protons and two neutrons in its nucleus.

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Three Steps of Nuclear Fusion

Color the picture.

J. Nguyen – Physical Science

F. Importance of Nuclear Fusion in the Sun1. During each step of the reaction, energy is

released which causes the sun to shine and to have a high temperature.

2. Begins with hydrogen and results in helium.

3. Helium has less mass than the heavier hydrogen that formed it. The lost mass is converted into energy during fusion reactions.

4. Nuclear fusion also occurs in other stars with elements other than hydrogen and helium.

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G. The sun’s interior has three main layers.1. The Core

a. At the center of the sun.

b. Makes up 10% of the sun’s total diameter of 1,300,000km.

c. Temperature is about 15,000,000°C and is made up of dense gas.

d. Most common nuclear reaction is fusion of hydrogen into helium.

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2. The Radiative Zonea. Zone that surrounds the core.

b. Temperature in this zone ranges from 2,000,000°C to 7,000,000°C.

c. Energy in this layer moves outward in the form of electromagnetic waves, or radiation.

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3. The Convective Zonea. Zone that surrounds the radiative zone.

b. Has a temperature of about 1,000,000°C.

c. Energy from the sun’s core moves through this zone by convection.

d. Convection is the transfer of energy by moving liquids or gases.

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H. The sun’s atmosphere has three main layers.1. The Photosphere

a. Also known as the light sphere or “sphere of light.” Referred to as the sun’s surface because this layer is the visible surface of the sun.

b. Temperature in this zone is about 6,000°C.

c. Energy is given off in the form of visible light.

d. Has dark spots (Sunspots) which are cooled areas of the sun.

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2. The Chromospherea. Thin layer of gases found above the photosphere

and is also known as the color sphere.

b. Layer of gases seems to glow with a reddish light.

c. Temperature ranges from 4,000°C to 50,000°C.

d. Gases of chromosphere move away from and toward the photosphere and sometime form jets.

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3. The Corona or Crowna. Outermost layer of sun that blends into space.

b. Huge cloud of gas heated by the sun’s magnetic field.

c. Temperature of about 2,000,000°C.

corona

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Layers of the SunColor and label the picture.

Chromosphere

Photosphere Convective Zone

Radiative Zone

Core

CoronaSun’s interior

Sun’s atmosphere

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I. Other information about the layers of the sun.1. Each layer blends gradually into the next.

2. Gaseous throughout the layers due to the high temperature at the core.

3. The enormous pressure and heat of the sun change the structure of the atoms within the core.

4. Both the chromosphere and corona are normally not seen from Earth because of the brightness of the blue sky during the day.

J. Nguyen – Physical Science

J. Solar Wind1. Atomic particles from the sun’s surface are

generally prevented from escaping into space by the corona.

2. Some particles can escape into space through some holes in the corona.

3. These escaped particles are called solar wind.

J. Nguyen – Physical Science

Write 15 questions for this section.

Highlight key words and phrases.

Draw a picture.

J. Nguyen – Physical Science

Summary (one paragraph) – Page 3The sun is a [star/planet]. The two most abundant

elements in the sun are ____________ and

___________. Nuclear fusion in the sun changes

hydrogen to ___________. This process releases

a lot of _________ which gives the sun its high

temperature. The three layers of the sun’s interior

are _________, ___________, and ___________.

The three layers of the sun’s atmosphere are

___________, ____________, and ___________.

J. Nguyen – Physical Science

II. 29.2 – SOLAR ACTIVITY

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A. Activities of the Sun1.The gases that make up the inner zones and

the atmosphere of the sun are in constant motion.

2.Parts of the sun rotate at different speeds.a. Points closest to the sun’s equator take only

23.5 days to make one rotation.

b. Points near the poles take 33 Earth days.

c. Astronomers calculate the average of the sun’s rotation to be 27 Earth days.

J. Nguyen – Physical Science

B. Sunspots1. The up and down movement of gases within the

sun’s convective zone along with the movement of the sun’s rotation results in magnetic fields.

2. The magnetic fields slow down convection and cause the sun to have cooler areas that can be up to 3,000°C cooler than surrounding regions.

3. These cooler areas of the sun appear darker than the warmer areas that surround them.

4. Cool, dark areas of gas within the photosphere that are caused by powerful magnetic fields are called sunspots.

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C. Prominences1. The sun’s magnetic field also causes other

disturbances in the solar atmosphere.

2. Prominences are great clouds of glowing gases that form huge arches that reach high above the sun’s surface.

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D. Solar Flares1. Another disturbance caused by the sun’s

magnetic field are solar flares.

2. Solar flare is a sudden outward eruption of electrically charged atomic particles.

3. Usually occur near sunspots.

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E. Magnetic Storms1. Solar flares can combine with solar wind to

cause magnetic storms on Earth.

2. They disrupt the magnetic field of Earth.

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F. Auroras1. Magnetic storms can cause auroras to form

in the earth’s sky.

2. Auroras are sheets of colored light produced by a magnetic storm in the Earth’s upper atmosphere.

J. Nguyen – Physical Science

Write 5 questions for this section.

You should have a total of 20 questions.

Highlight key words and phrases.

Draw a picture.

J. Nguyen – Physical Science

Summary (one paragraph) – Page 4Sunspots are _____________________________.

Sunspots are [cooler/warmer] than the surrounding

area. Prominences are _____________________.

Solar flares are ___________________________.

Magnetic storms are caused by the combination of

_________________ and _________________.

Auroras are _______________________.

J. Nguyen – Physical Science

Notes Points

Name __________________________________ Period _______

Chapter 29 Notes Points Earned

Points Possible

Highlight Key Words/Phrases 2

Copy Notes: pictures + color + label 20

Questions: 20 questions + arrows 10

Summary: 2 paragraph(s) 10

Drawings: 2 drawing(s) 4

TOTAL 46