lesson 3 | evolution of stars - ms. holm science -...

Lesson 3 | Evolution of Stars

Student Labs and Activities Page Appropriate For:Launch Lab 47 all studentsContent Vocabulary 48 all studentsLesson Outline 49 all studentsMiniLab 51 all studentsContent Practice A 52

Content Practice B 53

School to Home 54 all studentsKey Concept Builders 55

Enrichment 59 all studentsChallenge 60

Skill Practice 61 all students

AssessmentLesson Quiz A 63

Lesson Quiz B 64

Approaching Level On Level Beyond Level English-Language Learner

Teacher evaluation will determine which activities to use or modify to meet any student’s proficiency level.

46 Stars and Galaxies

Name Date Class

LESSON 3: 15 minutes

How can you identify fruits?Flowering plants grow from seeds that they produce. Animals depend on flowering plantsfor food. The function of the fruit is to disperse the seeds for plant reproduction.

Procedure1. Read and complete a lab safety form.2. Make a two-column table in your

Science Journal. Label the columnsFruits and Not Fruits.

3. Examine a collection of food items.Determine whether each item is a fruit.Record your observations in your table.

4. Place each food item on a piece ofplastic wrap. Use a plastic orparing knife to cut the items in half.

5. Examine the inside of each food item.Record your observations.

Think About This1. What observations did you make about the insides of the food items? Would you

reclassify any food item based on your observations? Explain.

2. How can the number of seeds or how they are placed in the fruit help with seeddispersal?

3. Key Concept What role do you think a fruit has in a flowering plant’sreproduction?

Stars and Galaxies 45

Launch Lab

Name Date Class

LESSON 3

Evolution of StarsDirections: Each of the sentences below is false. Make the sentence true by replacing the underlined word(s) witha term from the list below. Write your changes on the lines provided. NOTE: You may need to change a term to itsplural form.

black hole nebula neutronneutron star supernova white dwarf

1.Stars form deep inside black holes, which are clouds of gasand dust.

2.When a star that no longer contains helium casts off itsgases, its core turns into a hot, dense, slowly cooling sphereof carbon called a neutron star.

3.A supernova occurs when gravity is so great that no lightcan escape.

4.Neutron stars contain a dense core of nebulae, whichare particles in the nucleus of an atom.

5.A white dwarf is an enormous explosion that destroysa star.

6.A black hole is a dense core of neutrons that remains aftera supernova.


Content Vocabulary

Name Date Class

LESSON 3

Evolution of StarsA. Life Cycle of a Star

1. Stars have , meaning that they are born and, aftermillions or billions of years, they .

2. Stars form inside a(n) , which is a cloud of gas and dust.

a. causes the densest parts of a star-forming nebula tocollapse, forming a region called a(n).

b. As they contract, protostars produce enormous amountsof

3. A developing gets increasingly hotter over manythousands of years, heating up the surrounding gasand

a. The heated and dust eventually blow away, andthe becomes a visible . .

b. The gas and dust might later become or other objectsthat the star.

4. A stars spends most of its life cycle on the of theHertzsprung-Russell diagram.

a. When a star starts hydrogen into , it becomes a(n) starand remains there as it continues fusing into helium.

b. A star leaves the main sequence when its supply of has been nearly used up.

c. A massive star goes through a cycle near the end of its life in which it becomesa(n) several times

B. End of a Star

1. All stars in the same way, but stars in different ways.

2. -mass stars such as the Sun do not have enough mass to

fuse elements heavier than .


Lesson Outline

Name Date Class

Lesson Outline continued

3. Astronomers think that any star with a mass less than 10 times the mass of theSun will eventually become a(n) .

4. Stars that have a mass more than 10 times that of the Sun become a(n) , which is an enormous explosion that destroys the starat its center.

5. During a(n) , the collapse is so violent that the normalspaces inside atoms are eliminated and a(n) star forms.

6. Massive stars have a force of that is so strong that thematter gets crushed into a(n) .

C. Recycling Matter

1. The gas that give off at the of their life cycles gets recycled; it is the material that forms new starsand .

2. A(n) casts off hydrogen and helium, which becomespart of a planetary ; these gases can form new , not new , despite thenebula’s name.

3. A(n) produces a shock wave that pushes on the gasand in space.

a. Almost all the elements that are than hydrogen andhelium, including carbon, silicon, and oxygen, were released into theuniverse by

b. The force of causes innebulae to clump together and eventually form new and planets.


Name Date Class

LESSON 3: 15 minutes

How do astronomers detect black holes?The only way astronomers can detect black holes is by studying the movement of objectsnearby. How do black holes affect nearby objects?

Procedure1. Read and complete a lab safety form.

2. With a partner, make two stacks ofbooks of equal height about 25 cmapart. Place a piece of thin cardboardon top of the books.

3. Spread some staples over thecardboard. Hold a magnet under thecardboard. Observe what happens tothe staples.

4. While one student holds the magnetin place beneath the cardboard, theother student gently rolls a smallmagnetic marble across thecardboard. Repeat several times,rolling the marble in differentpathways. Record your observationsin the Data and Observations sectionbelow.

Data and Observations

Analyze and Conclude1. Infer What did the pull of the magnet represent?

2. Cause and Effect How did the magnet affect the staples and the movement of themarble?

3. Key Concept How do black holes affect nearby objects?

Mini Lab

Name Date Class

LESSON 3

Evolution of StarsDirections: On each line, write the term from the word bank that correctly completes each sentence. Some terms may be used more than once or not at all.

black hole fusion gravity massive star

nebula neutron star protostar red giant

star Sun supergiants supernova

white dwarf

1. A star forms deep inside a cloud of gas and dust called a .

2. causes the densest parts of the nebula to collapse.

3. A is formed and continues to contract.

4. The core of the protostar becomes hot and dense enough fornuclear .

5. Eventually the surrounding gas and dust blows away and a becomes visible.

6. Low-mass stars such as the Sun do not have enough mass tobecome .

7. A turns into a red giant, a larger red giant, and then a red supergiant.

8. After a low-mass star runs out of helium, the core is exposed and becomesa .

9. When the Sun in our solar system runs out of fuel, it will become a and then eventually a white dwarf.

10. A massive star does not become a . Instead it explodes.

11. A is an enormous explosion that destroys a star.


Content Practice A

Name Date Class

LESSON 3

Evolution of StarsDirections: Answer each question or respond to each statement on the lines provided.

1. What is a nebula, and how is it related to the formation of a star?

2. How does a protostar become a star?

3. How long does a star remain on the main sequence of the Hertzsprung-Russell diagram?

4. How does the mass of a star relate to the time it stays on the Hertzsprung-Russell diagram?

5. What steps does a massive star go through to become a red supergiant?

6. Describe the final stages of the Sun.

7. What happens to stars with more than 10 times the mass of the Sun?

8. What happens to the gas that escapes into space at the end of a star’s life cycle?


Content Practice B

Name Date Class

LESSON 3

Evolution of StarsDirections: Use your textbook to complete the activity.

For this activity, you will need one sheet of construction paper in each of several colors, suchas black, yellow, orange, red, and white. You will also need scissors, glue, and a compass fordrawing circles.

1. Review the information in your book about the Sun’s life cycle. List the stages of theSun’s life cycle here, in the correct order.

2. You will use the sheets of construction paper to make a time line of the various stagesin the Sun’s life cycle. The black sheet of paper will represent space. Use the compass tomake the Sun in various sizes depending on its stage. Choose appropriate colors as well.For example, the main sequence Sun of today would be yellow. The Sun as a red giantwould be red and larger than the yellow sun.

3. Carefully cut out the Suns and arrange them in order on the sheet of black constructionpaper. When you are satisfied with your arrangement, glue the Suns in place.

4. Describe the life cycle of the Sun, using your time line.


School to Home

Name Date Class

LESSON 3

Evolution of StarsKey Concept How do stars form?

Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If thestatement is false, change the underlined word(s) to make it t rue. Write your changes on the lines provided.

1. The cloud of gas and dust in which a star forms is called a galaxy.

2 The way in which a star forms does not depend on its mass.

3. Protostars form when gravity causes dense parts of star-forming nebulae toexpand.

4. Protostars contract until their cores are cold and dense enough for nuclearfusion.

5. A nebula glows brightly during the star-forming process.

6. The gas and dust that blow away from a protostar might later become planetsor other satellites.

7. All stars form in the same way. But stars die in different ways, depending ontheir luminosity.

8. Star-forming nebulae are cold, dense, and dark.

9. A protostar that is contracting produces enormous amounts of internal energy.

10. A protostar becomes invisible when the gas and dust that surrounds it blowsaway.

11. A star becomes a main-sequence star on the Hertzsprung-Russell diagram whenit begins to fuse hydrogen into helium.

12. The time that a star stays on the perimeter of the Hertzsprung-Russell diagramdepends on its mass.


Key Concept Builder

Name Date Class

LESSON 3

Evolution of Stars

Key Concept How does a star’s mass affect its evolution?

Directions: Number the events in each chart from 1 to 5 to show the sequence in the life of each type of star.

Medium Massred giant star

star-forming nebula

dead star

medium-mass protostar

white dwarf

High Massmassive protostar

red supergiant

formation of a neutron star or a black hole

star-forming nebula

explodes as a supernova

Directions: Circle the term in parentheses that correctly completes each sentence.

1. Lower-mass stars such as the Sun do not have enough (hydrogen, mass) to becomesupergiants.

2. High-mass stars collapse and explode as (protostars, supernovae).

3. A lower-mass star becomes a (white dwarf, black hole) instead of a supernova.

4. A supernova destroys a massive star and leaves behind a (red giant, neutron star).

5. A neutron star collapses into a black hole because of the force of (fusion, gravity).


Key Concept Builder

Name Date Class

LESSON 3

Evolution of StarsKey Concept How does a star’s mass affect its evolution?

Directions: Complete each concept map by writing the correct phrase from the list in the space provided.

• can become a black hole• can become a neutron star• collapses and explodes• dies more slowly• experiences a supernova• first becomes a red giant• ends up a white dwarf


Key Concept Builder

High-Mass Stars

Low- Mass Stars

Name Date Class

LESSON 3

Evolution of StarsKey Concept How is star matter recycled in space?

Directions: On each line, write the term from the word bank that correctly completes each sentence. Some termsmay be used more than once or not at all.

core black holes gravityhydrogen nuclear fusion planetary nebulaplanets remnant spacestars supernova white dwarf

1. When a star becomes a , it casts off hydrogen and heliumgases in its outer layers.

2. Much of a star’s gas escapes into at the end of its life cycle.

3. A is the expanding matter cast off by a star that is becominga white dwarf.

4. Originally, astronomers thought planetary nebulae were regions where were forming.

5. The gases in a planetary nebula can be used to form new .

6. A supernova releases an expanding cloud of dust and gas called asupernova .

7. Almost all elements other than hydrogen and helium were formed during explosions.

8. The intense heat during a supernova explosion causes iron elements in the to fuse together and form new elements.

9. Gases and other matter from planetary nebulae and remnants can come together to form new stars and planets.

10. is the force that causes new stars to form from recycled gasesand other materials.


Key Concept Builder

Name Date Class

LESSON 3

Into the DarknessScientists describe a black hole as a

collection of matter with a gravitationalpull that is so strong that nothing, noteven light, can escape from it. In the 1700s,researchers used Newton’s ideas aboutgravity to reach the conclusion that somestars might be so big that light could neverescape from them. Then, Einstein’s generaltheory of relativity appeared. UsingEinstein’s relativity equations, KarlSchwarzchild predicted the existence of adense object into which other objects couldfall but out of which no objects could evercome. Today, we call Schwarzchild’s objecta black hole.

A Magic Sphere?Schwarzchild also predicted a magic

sphere around such an object where gravityis so powerful that nothing can moveoutward. This distance is referred totoday as the event horizon, because noinformation about events occurring insidethis distance can ever reach us. Unable towithstand the pull of gravity, all materialthat goes past the event horizon is crusheduntil it becomes a point of infinite densityoccupying virtually no space. This point isknown as the singularity: Every black holehas a singularity at its center.

They Come in All SizesThere are three main types of black holes.

Stellar-mass black holes, the smallest andmost common, are the explosions of massivestars. Medium-size black holes are probablythe result of mergers of smaller black holes,and supermassive black holes have hugemasses and exist in the center of galaxies.

How Do We Know They Exist?In 2002, R. Schodel and his research

team reported the first observation of theorbit of a star around the black hole at thecenter of our galaxy, the Milky Way. Formany years, astronomers have put forththe theory that supermassive black holes—more than a million times the mass of theSun—exist in nearly every galaxy. No one,however, had found conclusive evidencethat supermassive black holes exist.

The Sun takes 230 million years to circlethe Milky Way, but the star that Schodelreports on will complete its orbit aroundthe black hole in 15 years. The speed of thestar’s orbit indicates that it is getting closerand closer to a huge gravitational pull. Forscientists, this orbit provides the evidencethat supermassive black holes exist.

Applying Critical-Thinking SkillsDirections: Answer each question or respond to each statement.

1. Describe what would be happening to you if you were falling into a massive blackhole. As you approach the event horizon, feet first, your body begins to be stretchedout. Why is that happening? What happens at the event horizon?

2. Predict what will happen when you travel past the event horizon.


Enrichment

Name Date Class

LESSON 3

The Lives of StarsStars exist because of gravity. The mutual gravitational attraction of particles in a thin,

gaseous cloud causes the cloud to collapse. As the cloud is squeezed to extremely highpressures, its temperature rises, igniting its nuclear reactions, and a star is born.

Research and Diagram the Evolution of Stars1. Research the evolutionary stages of three types of stars.

a. low-mass stars

b. medium-mass stars (about the size of the Sun)

c. massive stars

2. On chart paper, draw a diagram of the evolutionary stages of each type of star, beginningeach one with a nebula. Draw the stages in color and label each stage.

3. On each diagram, label the star in its main-sequence stage with its temperature range indegrees Kelvin.

Research Notes:


Challenge

Name Date Class

Make and Use Graphs LESSON 3: 45 minutes

How can graphing data help you understand stars?How can you make sense of everything in the universe? Graphs help you organize information.The Hertzsprung-Russell diagram is a graph that plots the color, or temperature, of stars againsttheir luminosities. What can you learn about stars by plotting them on a graph similar to theH-R diagram?

Materialscolored adhesive stars of various sizes

Learn ItDisplaying information on graphs makes iteasier to see how objects are related. Lineson graphs show you patterns and enable youto make predictions. Graphs display a lot ofinformation in an easily understandableform. In this activity, you will make anduse graphs, plotting the temperature, thecolor, and the mass of stars.

Try It1. Using the graph paper, draw a graph

like the one shown in your book.

graph paper

2. Use the color and temperature data inthe table below to plot the position ofeach star on your graph. Mark the pointsby attaching adhesive stars to the graph.

3. If stars have similar data, plot them ina cluster. Label each star with its name.

4. Draw a curve that joins the data pointsas smoothly as possible.

5. Make another graph and plottemperature v. mass of the stars in thetable. Use the grid on the next page.

Star Color Temperature (K) Mass in solar massesSun Yellow 5,700 1Alnilam Blue-white 27,000 40Altair White 8,000 1.9Alpha Centauri A Yellow 6,000 1.08Alpha Centauri B Orange 4,370 0.68Barnard’s Star Red 3,100 0.1Epsilon Eridani Orange 4,830 0.78Hadar Blue-white 25,500 10.5Proxima Centauri Red 3,000 0.12Regulus White 11,000 8Sirius A White 9,500 2.6Spica Blue-white 22,000 10.5

Vega White 9,900 3


Skill Practice

Name Date Class

Skill Practice continued

Apply It6. All of the stars on your graph are main-sequence stars. What is the relationship

between the color and the temperature of a main-sequence star?

7. What is the relationship between the mass and the temperature of a main-sequencestar? How are color and mass related?

8. Key Concept Which star would be the most likely to eventually form a blackhole? Why?


Name Date Class

LESSON 3

Evolution of StarsTrue or FalseDirections: On the line before each statement, write T if the statement is true or F if the statement is false. If thestatement is false, change the underlined word(s) to make it true. Write your changes on the lines provided.

1. A cold, dense, dark cloud of gas and dust in space is called a nebula.

2. The gravity of a white dwarf is so great that light cannot escape it.

3. A supernova is the explosion of a massive star.

4. A dense core that remains after a supernova is called a black hole.

5. Stars move onto the main sequence when they begin to fuse hydrogen into carbon.

Multiple ChoiceDirections: On the line before each question, write the letter of the correct answer.

6. Which sequence correctly shows how stars form?A. nebula forms → nebula collapses → protostar forms → fusion beginsB. protostar forms → nebula forms → fusion begins → nebula collapsesC. nebula forms → protostar forms → nebula collapses → fusion begins

7. Which statement is true of stellar evolution?A. Black holes become neutrons stars.B. Low-mass stars become supergiants.C. The most massive stars do not become white dwarfs.

8. How do stars recycle matter?A. They stay on the main sequence.B. Black holes form and recycle stellar gas for new stars.C. Gravity pulls together gases and matter from old stars to create new ones.


Lesson Quiz A

Name Date Class

LESSON 3

Evolution of StarsCompletionDirections: On each line, write the term from the word bank that correctly completes each sentence. Not allterms are used

black hole main sequence star nebula neutron starplanetary nebula protostar red giant red supergiantsupernovae white dwarf

1. A is a hot, dense, slowly cooling sphere of carbon thatforms at the end of the life cycle of stars such as the Sun.

2. A star is born deep inside a cloud of gas and dust called a .

3. Stars that are more than 10 times more massive than the Sun will explodeas .

4. A forms when the most massive stars collapse.

5. A small, extremely dense core of neutrons that remains after a supernova is calleda .

Short AnswerDirections: Respond to each statement on the lines provided.

6. Summarize the formation of a star.

7. Describe how a star’s mass affects the length of its life cycle.

8. Explain how star matter is recycled.


Lesson Quiz B

lesson 3 | evolution of stars - ms. holm science -...

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