Stars and Galaxies

Chapter 25

Section 1 The Study of Stars

Objectives:Describe the electromagnetic spectrumExplain how reflecting and refracting telescopes workCompare and Contrast optical telescopes and spectroscopesInfer the relationship between the frequency of electromagnetic waves and their wavelength

Skills Warm-up

Star WordsWrite as many words as you can to describe stars from just observing them.Write something you know about stars but can’t tell by just looking at them.Compare your words with your classmates.

StarsStars are swirling, glowing balls of ______

There are > 200,000,000,000 billion

The _______ is very important to earth, but it is just an average ____

Many other stars are much _______ and ________

How are stars studied?

Electromagnetic Spectrum

All stars produce energy in the form of

___________ __________:________ ________

________ ________

________

________

Each type of energy has a

characteristic ________ and _________

____________ ________ - all types of electromagnetic wave energy, from very low frequency to very high frequency

Optical Telescope

Microscopes use _______ to collect visible light from ______ _______ and produce _________ that are much __________

________ __________ work the same way, using ________ or _________ to collect visible light

The only difference is that the light comes from a ______ ______ and _______ _______

It then makes the distant object look ________ and _________

Optical Telescopes

________ telescope – uses ______ to collect and focus visible light

_______ telescope – uses ______ to collect and focus visible light

Optical Telescopes

The ______ a mirror or lens, the ______ the image it can make

But, if they get too big, they _____ from their own _______

The telescope with the largest single mirror (5 m in diameter) is in the _____ _________ in California

SpectroscopesA star’s ______ _______ has a characteristic spectrum of light of different wavelengths because each ________ __________ in the star blocks particular wavelengths of light

By looking at a star’s ________, scientists can figure out what its _________ ________ is

A _________ contains a _______ to separate the light and a small optical telescope to see the spectrum

Stars contain ~ 75% ________ and 22% _______

Radio TelescopesCollect ______ _______ from space

________ _______collects waves that are reflected to the antenna and then ___________

Good for studying -______ and ________ and have helped us learn about our own ________

ActivityWork in pairs

Complete Skills Worksheet 25.1

Please hand in completed worksheet by tomorrow – if necessary, finish for homework

Section 2 Characteristics of Stars

Objectives:Relate the temperature of a star to its colorExplain how measurements of parallax are used to measure a star’s distance from earthContrast absolute magnitude and apparent magnitudeInterpret data from an H-R diagram

Skills Warm-up

Stars in the SkyMake a list of the sun’s characteristics.Which of these do you think are shared by all stars?Which characteristics of the sun do you think are different from other stars?

Star Classification

Scientists classify stars according to :

____________________________________

Color and Temperature

The color of a star is related to its ___________

Distance of StarsHold your finger in front of your face.

Look at it with your left eye closed.

Then look at it with your right eye closed.

Does your finger seem to move or change position relative to the background?

Distance of Stars

Now find an object across the classroom from you.

Look at it with your left eye closed.

Then look at it with your right eye closed.

Does this object move position as much as your finger did?

Distance of Stars

___________ – apparent change in the position of an _______ due to change in position of the __________

Scientists use parallax to determine the _________ of a star from __________

As earth moves around the sun, _______ stars appear to ______ position relative to more __________ stars

The ________ a star is to earth, the __________ its apparent change of position

Measurements of change in position can be ___________ into measurements of distance

Distance of Stars

Distances of stars are so ________ - you can’t use any normal _______ _____ ____________Scientists use ______________

The distance that light, travelling at a speed of 310,000 km per second, will cover in 1 year Equal to 9.5 trillion kmProxima Centauri – ________ star to earth at 4.2 light-yearsMost stars are hundreds of light-years away

Magnitude of Stars

______________ – brightness of starsThe ___________ the star, the _________ its number of magnitude

A star with a magnitude of -2 is brighter than one with a magnitude of 2

___________ magnitude – a star’s brightness from earth

Doesn’t really tell you how much light is given off

___________ magnitude – actual brightness of a star from a standard distance

Hertzsprung-Russell Diagram

Two scientists graphed a large number of stars based on their ________ __________ and _____________

4 Types of Stars:______ __________ – stars grouped in a diagonal band from hot/bright to cool/dim

____________ – very bright stars that range from cool to medium/hot

_______ _______ – medium bright but cool

_______ _______ – low magnitude but relatively hot

ActivityWork in pairs

Complete Skills Worksheet 25.2

Please hand in completed worksheet by tomorrow – if necessary, finish for homework

Section 3 Life Cycles of Stars

Objectives:Explain how stars come into beingDescribe the stages of a star’s lifecycleContrast the different ways in which high-mass and low-mass stars end their life cyclesPredict what will happen for the rest of the sun’s lifecycle

Skills Warm-up

The Life of StarsList and describe each stage of the human life cycle.How do you think the human life cycle is different from that of a star?

Star LifecycleHuman life cycle lasts about _____ ________

Born

Infant

Toddler

Child

Teenager

Adult

Senior citizen

Star LifecycleStars are also _______, then _______ and eventually ______

Star life cycle lasts _______ __ _______

Stars in the sky are at _________ stages

Our sun is about ____ way through its ____________ year life cycle

Birth of a Star______ – a cloud of _____ and ______ where stars are born

Made of mostly _________ with _______ and _______

Gravity causes the spread out particles of matter to ___________

Matter starts to heat up and becomes a ____________

Protostars don’t shine, but give off _________ energy

Eventually they become hot enough for ________ to occur and a star is born

Low Mass-Stars – mass is less than ______ that of

the ______Low-Mass Star Lifecycle:

Begins as a ____________star but gradually the supply of _________ is changed by fusion into _________

_________ _________– core of star starts to collapse

becomes hotter and denser

helium is converted to __________

short part of life cycle

________ __________– Star cools and collapses inward to be a _________ dwarf

Eventually no light is given off and is a __________ dwarf

High Mass-Stars – mass is more than ____ that of

the _____High-Mass Star Lifecycle:

Uses up __________ at a much faster rate

____________ __________– ___________ runs out

Core collapses

Outer layers expand greatly

____________ _________– Pressure builds up and causes a massive ____________

When only tiny core of neutrons remains it becomes -

_________ _____– dense core of neutrons

________ ________– so dense and gravity so strong nothing can escape it

ActivityWork in pairs

Complete Skills Worksheet 25.3

Please hand in completed worksheet by tomorrow – if necessary, finish for homework

Section 4 Galaxies and Star Groups

Objectives:Describe the 4 types of galaxiesExplain what a constellation is and how it differs from a galaxy or star clusterExplain how scientists know the universe is expandingPredict how the constellations will look in the distant future

Skills Warm-up

Lions and Tigers and …..When you look at the sky on a clear night, what shapes do the stars make?Draw what they look like to you.

Galaxies______ – collection of _____, nebulae, _______, dust, and _______ that move through space as a unit – held together by gravity

There are at least __ ______ galaxies in the universe – ours is the ______ ____

Types of Galaxies

_______ – flat disk with a bulge in the middle

Have long spiral arms that swing out and rotate like a _________

Contain large amounts of ____ and ______

Example – _____ _____

Types of Galaxies

_____ ______– similar to spiral but arms are attached to a straight bar shape

Bar is much _______ and ________ than the arms

______ common than spiral

Example – _______ _______

Types of Galaxies

__________ – football shaped

Rotate differently than spirals – more ________

Contain ______ gas and dust

Example – _______

Types of Galaxies

________ – don’t have regular shapes

_____ greatly in size

____ common type

Example – _____ ________ ______

Constellations_____ ________shaped like people, animals, or objects

There are ______ official constellations

The stars in constellations may look like they are close together from earth, but they are not

Constellations are important because

_______________________

_______________________

_______________________

Expansion of the Universe

______ ______ _______:15 – 20 million years ago all matter in the universe was packed into one ______ ________

The fireball exploded, spreading ______ and ________ out in all directions

As matter cooled, the force of gravity pulled together the particles of matter to form _____ ____ _________

The universe was born!!!

Expansion of the Universe

What’s the proof???

The ___________ EffectThe light waves from an object _____ ______from earth are spaced more ______ apart than if it were _______ _______

The waves appear to have a longer _________ than they really have and shift to the _____ ______ of the visible light spectrum

All other galaxies have a red shift in their spectrums which means they are moving _____ from earth

http://video.search.yahoo.com/video/play?ei=UTF-8&fr=yfp-t-701&fr2=tab-img&p=doppler+effect+audio&vid=1078797468712&dt=30145135&l=78&turl=http%3A%2F%2Fts1.mm.bing.net%2Fvideos%2Fthumbnail.aspx%3Fq%3D1078797468712%26id%3D9e034c60fc3e4bfc86990a9e32a16274%26bid%3DQwi6yfYlRKH4KQ%26bn%3DThumb%26url%3Dhttp%253a%252f%252fvideos.howstuffworks.com%252fdiscovery%252f27963-assignment-discovery-doppler-effect-video.htm&rurl=http%3A%2F%2Fvideos.howstuffworks.com%2Fdiscovery%2F27963-assignment-discovery-doppler-effect-video.htm&tit=Assignment+Discovery%3A+Doppler+Effect&sigr=12th87akt&newfp=1

Doppler Effect Video

Beyond the Solar System

Do you think that reaching other stars may some day be possible??????

Problems:_______ – a spaceship travelling at the speed of light would take over 8 years to make a round trip to the nearest star

________ – we don’t have a spaceship that can travel anywhere near the speed of light

_____ _______– it would be difficult for people to travel, so scientists are looking to send data collecting devices instead

ActivityWork in pairs

Read Unit 9: The Milky Way Galaxy and Beyond

Complete attached worksheet “Quick Check”

Please hand in by tomorrow – if necessary, finish for homework

Debate

I will split the class into 2 teams and assign which side of an issue your team will be arguing on.

Take ½ of the class period with your team to come up with arguments to support your part of the issue.

Pick 4 representatives from each team to debate against the opposing team.

Issue:Is space exploration worth the cost????

How valuable is more knowledge about the universe?

What could be done with the money that is currently being used for space exploration?