Focus on California 8th Grade Physical Science Textbook Chapter 12 Earth, Moon, and Sun

Chapter , Moon , and Sun Standards ew Unbalanced cause ( in velocity . As a basis for understanding this concept Students know the of gravity in and main the shapes of , stars , and the may system The structure and tion of the universe can be learned from studying stars and galaxies and their evolution . As a basis ( or understanding this concept Students know that stars an the some of for all ob , in outer space and that the Moon and ets shine by reflected , not by their own . Students know the ance , general ( alive position and size , and motion of in the system , planets . and This time lapse photo shows an ) the moon as it rises over the Gate in San 459

A Preview . Moon , and Sun Focus on . I ?

BIG Ide What events are caused by the motion of Earth and the moon ?

Check What You Know Imagine that you are looking up at a full moon in the sky . Why is the moon so bright ?

Does the moon produce its own light , like a flashlight , or does its light come from somewhere else ?

Explain your reasoning . 12 459 The Images shown here represent some of the key terms in this Vou can use this vocabulary skill to help you understand the meaning of some key terms in this chapter . Latin Word Origins Many science words come to English from Latin . For example , the adjective , which means of the sun , comes from the word , or Use the Latin words in the table below to you remember the Key Terms . Latin Word Meaning Key Terms Apply It ! Review the Latin words and meanings in the chart . Look at the meaning of crater . Predict what a crater might be if it were seen on the surface of the moon . Revise your as needed .

Chapter 12 Vocabulary , I astronomy axis revolution ( sumac Section ' Universal Law of Gravitation mass weight mama law of motion Section acne penumbra lunar eclipse ude spring tide neap tide Section . telescope mama ( rater meteoroid ) a ' IV ! Build Vocabulary ( Chapter 12 461

, Hi I ( I ' ea , I , Skill Sequence Some pro ( in ' i ( occur as part of a A cycle is a continuous process or sequence of events that does not have an end . When the event is over , the first event begins again . The changing seasons on Earth are an example of a cycle Use a cycle diagram to show a . Write the first event in a circle at the top of the page . write each event in sequence , moving clockwise . Draw arrows to connect each event to the one that occurs next . Seasons of the Year , Winter I , Fall Hi Glimmer Apply It ! Review the diagram . Why is using a cycle diagram a good way to explain the seasons . Alter you read about the seasons in Section , create your own cycle diagram of the seasons Include information about the tilt of Earth axis and how the tilt the seasons in the Northern and Southern Hemispheres , As you read Section , prepare a cycle diagram showing lour mayor phases of the moon .

, Track the Moon How does the moon move across the sky ?

How does its appearance change over the course of month ?

In this investigation , you will observe how the position and apparent shape of the moon change over time . Your Goal To observe the shape of the moon and its position in the sky every day for one month To complete this project , you must observe the compass direction in which you see the moon , its phase , and its height above the horizon use your observations to explain the phases of the moon develop rules you can use to predict when and where you might see the moon each day Plan It ! Begin by preparing an observation log . You will record the date and time ol eath observation , the and height of the moon , a sketch of its . and notes about cloud Lover and other . Observe the moon every clear night , looking ( or patterns . Make a map of your observation site on which you will direction of the moon You ( an measure the moon height in degrees above the horizon by making a fist and holding it at length . One fist above the horizon is 10 , two lists are 20 , and so on . On at least one day , compare your observations of the moon an hour or two apart . your observations are complete , prepare a presentation of your results . Your presentation should include a set of graphs and a dIS ( of any patterns that you noticed . Chapter

00 Students know the ance , general composition , relative position and size , and motion of objects in the solar system . planets , planetary satellites . comets . and asteroids How does Earth move in space ?

What causes the cycle ol seasons on Earth ?

Key Terms I astronomy I axis I rotation revolution I orbit I calendar I solstice I equinox Flaunt I Ancient Egyptian Farmers Egyptian watched the sky in order to be prepared to plow and plant their fields 4640 Earth in space I ! Sli What Causes Day and Night ?

Place a lamp with a bare bulb on a table to represent the sun . Put a globe at the end of the table about meter away to represent Earth . Turn the lamp on and darken the room , which parts of the globe have light shining on them ?

Which pans are in shadow ?

Find your location on the globe . Turn the globe once . Notice when it is your location and when it is . Think It Over Making Models What does one complete turn of the globe represent ?

In this model . how many seconds represent one day ?

How could you use the globe and bulb to represent a year ?

year . Egyptian farmers the of the Nile River . For uf years . planting was ruled by it . As 00 ! as the Nile ) withdrew , the had to bi ready to plow and plant their fields along this river . the wanted to predict when the flood would occur . Around 5000 ( people noticed that the bright star Sirius first visible in the early morning sky every year shortly . The used this to year flood . ancient Egyptians were among the line ! people to study the study moon . stars . and other objects in space is called .

How Earth Moves Ancient the of the sun and the moon as they appeared to travel across the sky . It seemed to them as though was standing still and the sun and were moving . Actually . the sun and moon seem to move across the ' day because is rotating on its axis . also ' around the sun . Earth moves through space in two major rotation and revolution . Rotation look at Figure . The line that through and the North and South is Earth axis . The spinning of Earth on its axis is called rotation . rotation causes day and night . As rotates ward . the sun appears to move westward anus the . It is day on the side of lining the sun . continues to turn to the east , the to in the west . Sunlight can ! reach the side ol Earth lacing away from the sun . so it is night there . It takes about hours to rotate once . you know . each 14 hour cycle ofday and night is called a day . mu ! Earth Revolution In addition to rotating on in ' Earth travels . around the sun . shown in Figure a revolution is the 515 movement oi one object another . One complete of around the sun is called at year . at path , or orbit , an it revolves around the sun . Earth orbit is not quite circular . It is a slightly elongated . or ellipse . similar to the movement of the figure skater as she spins Earths orbit Flaunt Revolution Earth revolves around the sun just as a speed skater travels around the renter of a rink during a ram . Applying Concepts one complete revolution of Earth around the sun railed ?

Chapter 12 465 the Cycle of the Year For thousands of years . people have used observations of the sky to keep track of the of year . 4660 Science and History Calendars People of many different cultures have struggled to establish calendars based on the length of time that Earth takes to revolve the sun . A is a system of organizing time that defines the beginning , length . and of a year . The ancient Egyptians created one of the calendars . Egyptian astronomers counted the number of days between each appearance of the star Sirius in the morning . In this way . they found that there are about 365 days in a year . Dividing the year into smaller parts was also . Early people used moon cycles to divide the year . The time from one full much to the next is about 29 days . A year of of these adds up to only 354 days . The ancient Egyptian calendar had 12 months of 30 days each . with an extra days at the end . 1300 ac Chinese mil ! of the sun , planets . and other they see In the night sly . Chinese astronomers that the .

The Romans borrowed the Egyptian calendar of 565 days . But in fact . Earth orbits the sun in about 365 . days . The Romans adjusted the Egyptian calendar by adding one day every four years . You know this fourth year as leap In a leap year . February is given 29 days instead of its usual 28 . Using a system of leap years ) ensure that annual events , such as the of summer . occur on about the date each year . The Roman calendar was 01 ) by a little more than utes a yea Over the centuries , these minutes added up . By the the beginning of spring was about ten days too early . To straighten things out , Pope Gregory dropped ten days from the year 1582 . He also made some other minor changes to the Roman system to form the calendar that we use today . What a leap year ! 600 Korea The is built . The hollow . tower is the oldest existing observatory in the world . The tower was probably used for astronomical observations . Writing Dialogue Research one at the accomplishments discussed in the timeline . Write a , or dialogue . in which two people from the time and ( that made the discovery or structure discuss its importance in their lives . Examples might include their work or the timing of their celebrations . AD . 1600 Astronomers use a variety oi astronomical instruments . including . It on observatory in Istanbul . were used to predict the positions of stars and planets .

haunt sunlight Striking Earth Near the equator , sunlight strikes Earth surface more directly and is less spread out than near the poles . Relating Cause and Effect Why is it usually ( older near the poles than near the equator ?

Sun Shadows The sun shadow changes predictably through the day . On a sunny day . stand outside in the sun and use a compass to find north . Have your partner place a craft stick about one meter to the north of where you are standing . Repeat for east . south , and west . Insert a meter stick in the ground at the center of the craft sticks . Make sure the stick is straight up . Predict how the shadow will move throughout the day . Record the direction and length of the sun shadow at noon and at regular intervals during the day . Predicting How did the movement ol the shadow compare with your prediction ?

How do you think the dire ( tion and length of the sun shadow at these same times would change over the next six months ?

4600 Less direct sunlight Most direct sunlight Less direct sunlight The Seasons on Earth hit ! pla ' outside the tropics and polar regions have four tinct inter . spring . summer . and autumn . But there are great in temperature from place to place . For , it is generally warmer the equator than the is this so ?

Sunlight Earth Figure I shows how sunlight strikes surface . Notice that sunlight hits Earth surface most directly near the equator . Near poles , sunlight arrives at a steep angle . As at , it is spread out a greater am ) That is why it is near the equator than near the poles . Earth Tilted Axis If axis were straight up and down relative to its orbit . temperatures would remain fairly . There would hi no . Earth has its axis is tilted as it revolves around the sun . Notice in that Earth axis is always tilted at an angle of from the . As Earth around the sun , the and ofits axis is tilted away from the sun for part of the your and toward the sun for part of the year . and winter are caused by till as it around the sun . The in seasons is not caused by changes in Earth from the sun . In fact . Earth is farthest from the sun when it is in the . when is Earth farthest train the sun ?

The Seasons The cycle at the seasons is caused by the tilt of Earth axis as It revolves around the sun . June Solstice The north end of Earth axis is tilted toward the sun . It is summer in the Northern Hemisphere and winter in the Southern Hemisphere . Mirth and September Neither end of Earth axis toward the sun . Both hemispheres receive the same amount of energy . September Equinox Co ( ICU kart Far Seasons Visit ( Web ( ode Lip 5011 December Solstice The south end of Earth axis is tilted toward the sun . It is summer in the Southern Hemisphere and winter in the Northern Hemisphere . The height at the sun above the horizon varies with the season Interpreting Graphics When is the sun at its height in the Northern Hemisphere March and September

I the ' from and Summer in the Southern Hemisphere ( left ) at the same time as winter In the Northern Hemisphere ( right ) Similarly , when it is spring in the Southern Hemisphere . it is tall in the Northern Hemisphere . Interpreting Photographs In which direction was Earth axis pointing at the time that each of the photographs was taken ?

470 In an . Earth In June In une . the north end of axis is tilted toward the sun . In the Northern Hemisphere . the noon sun is high in the sky and there are more hours of daylight than ness . The combination of direct rays and more hours of sunlight heats the surface more in lune than at any other time of the year . It is summer in the Northern Hemisphere . At the same time south of the equator , the sun rays are less direct . The sun is low in the sky and days are shorter than nights . The combination of less direct rays and fewer hours of sunlight heats Earth surface less than at any other time of the year . It is winter in the . Earth In December In December , people in the Southern Hemisphere receive the most direct sunlight . so it is summer there . At the same time . the sun rays in the Northern are more slanted and there are fewer hours of daylight . So it is winter in the Northern Hemisphere . The sun reaches its furthest position north or south of the equator twice each year . Each of these days . when the sun is farthest north or south of the equator , is known as a ( stis ) The day when the sun is farthest north of the equator is the summer solstice in the Northern sphere . It is also the winter solstice in the Southern sphere . This solstice occurs around lune each year . It is the longest day of the year in the Northern Hemisphere and the day of the year in the Southern Hemisphere . Similarly , around December 21 , the sun is farthest south of the equator . This is the winter solstice in the Northern sphere and the summer solstice in the Southern Hemisphere .

Target Reading Skill sequence your diagram Reviewing Key Concepts in ! nephews ' is tilted toward or away from sun . This twice zi year , when he noon suit is directly til the equator . of ( days is known as an equinox , which equal During an equinox . day and night are each about 12 hours long an Earth . The ( nox occurs around and the beginning of spring in the Northern Hemisphere . The autumnal equinox occurs around September 22 . It marks the beginning of fall in the Northern . what is an BA Writing . in Science what seasons occur where you live ?

Assessment Section of the summits tu help WEl the . Identifying Tut arc the urn Earth as it travels through space ?

93709739 I ) Explaining Which motion mum day and night ?

ma a . Relating Cause and Effect What causes the ?

i . Comparing and What are solstice and EWW i ?

How are they the ?

the if Earth If 95 as it moves the sun . were not tilted on its axis ?

900 Owner ! 411 Reasons for the Seasons Problem How does the tilt of Earth axis the light received by Earth as it revolves around the Skills Focus making models , observing , inferring , predicting Materials ( per pair of students ) books paper pencil protractor I toothpick acetate sheet with thick grid lines drawn on it plastic foam ball marked with poles and equator Procedure . Make a pile of books about 15 high . Tape the acetate sheet to the head of the flashlight Place the on the pile of books . Carefully push a pencil into the South Pole of the plastic foam ball , which represents Earth . Use the protractor to measure a tilt of the axis of your Earth away from your sun , as shown in the top diagram . This position represents winter in the Northern Hemisphere . Hold the pencil so that Earth is steady at this angle and about 15 from the flash light head . Turn the flashlight on , Dim the room lights . The square on the acetate should show up on your model Earth . Move the ball closer if necessary or dim the room lights more Observe and record the shape of the squares at the equator and at the poles . 472 . Carefully stick the toothpick straight into your model Earth about halfway between the equator and the North Pole . Observe and record the length of the shadow . Without ( hanging the tilt . turn the pencil to rotate the model Earth once on its axis . Observe and record how the shadow of the toothpick changes . Tilt your model Earth the light . as shown in the bottom diagram . This is summer in the Northern Hemisphere . Observe and record the shape of the squares at the equator and at the poles . Observe how the toothpick shadow changes , 10 . Rotate the model Earth and note the shadow pattern .

Analyze and conclude . Observing When it is winter In the Northern Hemisphere , which areas on Earth get the most concentrated light ?

Which areas get the most concentrated light when it is mer in the Northern Hemisphere ?

Observing Compare your observations of how the light hits the area halfway between the equator and the North Pole during ter ( Step ) and during summer ( Step ) Inferring If the squares on the ball from the acetate become larger , what can you infer about the amount of heat in each square ?

According to your observations , which areas on Earth are consistently coolest ?

which areas are consistently est ?

Why ?

Predicting What time of year will the pick shadow be longest ?

When will the shadow be shortest ?

Drawing Conclusions How are the amounts of heat and light received in a square related to the angle of the sun rays ?

Use your observations of an model to write an explanation of what causes the seasons . More to Explore You can measure how directly light from the sun hits Earth surface by making a shadow stick . You will need a or pole about long . with the help ol your teacher , push the stick partway into the ground where it will not be disturbed . Make sure the stick stays vertical . At noon on the first day of every month , measure the length of the stick shadow . The shorter the shadow , the higher the sun is in the sky and the more directly the sun rays are hitting Earth . At what time of the year are the shadows longest ?

Shortest ?

How do your observations help explain the seasons ?

413 Section . Standards War Students the role of gravity in forming and maintaining the shapes of planets , stars . and the solar system . What determines the strength of the force oi gravity between two What two combine to keep the moon and Earth in orbit ?

Key force I gravity Universal Law oi Gravitation mass weight inertia Newton lirst law oi motion 474 Integrating Physics Gravity and Motion Can You Remove the Bottom Penny ?

Plate 25 or so pennies in a stack on a table . Write down your prediction of what will happen if you attempt to knock the bottom penny out of the stack . slide a ruler along the surface oi the table and strike the bottom penny . Observe what happens to the of pennies . Repeat Step several times , knocking more pennies from the bottom of the stack . Think Over Developing Hypotheses Explain what happened to the stack of pennies as the bottom penny was knocked out of the stack . Earth revolves around the sun in a nearly circular orbit . The moon orbits in the saint way . But what keeps Earth and the moon in orbit ?

Why do this ) iust lly oil into ?

The first person to answer these questions was the . Newton . Lite in his hit . story of how watching an apple fall from a tree in loot had him think about the moon orbit . that there must bi force acting II Earth and the moon that the moon in orbit . Recall that force is push or a pull . Most everyday to be in . that the ' that holds thi moon in orbit is in that it acts over long ) objects that are not in . Gravity Newton , that thi that pulls an apple to the ground also pulls moon toward . keeping it in orbit . This force . called gravity , all objects toward each other . in day . most scientists thought that forces on dill from in . Although did not ' I ' hi lirst to ' that gravity occurs ' Universal Law of Gravitation states that every obiect in attracts object .

TIM ' ol is im in , mu . The of the fora of gravity objects on two factors the masses of the and the distance between them . Gravity , Mass , and Weight ' i ( law ui gnu . uf Mound you . this hook . are pulling un you . Von are pulling on them . do you pull you and ?

the . ih in ! gun ii ) in ! the , at the you . mass is the uf . i ' is so . 11 lime un mu than this docs . writs In . Luigi enough to the in . also ( i em , Ai ' i in this ' you study ( The . un an is the weight . an mu , on its location . on thy mum you unc sixth in weight mi ( I ( ui the mom mu would that ul ' i gI ) Gravity and Distance 01 is ' lwo , then in as . The ' distance ' it . tum of gun ily ' lu mic ! in . What is an object weight ?

Flaunt Gravity , Mass . and Distance The oi the of between two depends on their masses and the between them . wring Haw forte ( hang ?

it the ?

Gravity attracts ali toward one another if mass increases , nice aim It ' increases . arm FIGURE Earth Over the Moon form a gravity holds duh and the moon Math Algebra and Functions Math Data Gravity Versus Distance As a rocket leaves a planets surface , the force of gravity between the rocket and the planet ( Use the graph at the right to answer the questions below . Reading Graphs What is the force of gravity on the rocket at the planet surface ?

Reading Graphs What is the force of gravity on the rocket at a distance of two units ( twite the planet radius from its center ) Making Generalizations to the graph , is the relationship between gravity and distance linear or nonlinear ?

Explain . Drawing Conclusions In general , how does the force of gravity pulling on the rocket change as the distance between it and the planet increases ?

Predicting Estimate the of gravity on the rocket at a distance of five units . Million newtons ) a Distance From Planet Center ( Planet ?

raring ) Inertia and Orbital Motion If the suit and Earth are constantly pulling on one another because of gravity . why doesn Earth fall into the sun ?

why does the moon crash into Earth ?

The fact that such collisions have not occurred shows that there must be factor at work . That factor is called inertia . Inertia The tendency object to resist a change in motion is inertia . You feel the of inertia every day . When you are riding in a car and it stops suddenly , you keep moving forward . you did have a seat belt on , your inertia could cause you to bump into the car windshield or the seat in front of you . The more mass an object has . the greater its inertia . An object with greater inertia is more to start or stop . Newton slatted his ideas about inertia as a law . Newton motion says that an object at rest will stay ' at rest and an object in motion will stay in motion with a For Links on gravity . it speed and direction unless acted on by an unbalanced force . web ( ode lead . 47 !

! Moon motion without gravity Orbital Motion Why du Earth the moon in Il orbits ?

Newton concluded that two and to keep Earth in orbit around the sun and the moon in orbit around Earth . in ) gravity pulling the ) lI it . the in straight line . At the same time . the . If not gravity , inertia Actual orbit Flaunt Gravity and Inertia A of gravity and inertia keeps the moon in orbit around Earth It were no inertia would cause the moon to travel in a straight lune . Interpreting Diagrams What would happen to the moon were not moving in orbit ?

cause the to move space in at linc . In the way . Earth around thu sun gravity pulls ( keeps it ahead . Section Assessment Writing , Vocabulary Skill Word Origins Huw ( Latin word gravity help you its , Reviewing Key Concepts MINT Summarizing What is Law ul ?

Hill . Reviewing ' the at two ?

Predicting Suppose the to . Earth and the Ix ' mu to keep Earth in orbit around Mill ?

Applying ( sun ?

ting How would Earth mow it the sun ?

its , your . clue and Effect Suppose you took a trip to the moon . Write a paragraph how and why your weight would . Would your mass change to 07 Chapter I ! 477 Focus students know the role of gravity In forming and ing the shapes of planets . stars . and the system . Students know that stars are the source of light for all bright objects in outer space and that the Moon and planets shine by sunlight . not by own light . what causes the phases ot the ?

What are solar and lunar eclipses ?

What causes the tides ?

Key Terms phase ' solar eclipse umbra penumbra lunar tide I spring tide ' tide 47 ! Phases , Eclipses , and Tides Warm Up How Does the Moon Move ?

Place a quarter flat on your desk to represent Earth , Put a penny flat on your desk to represent the moon . One side of the moon always faces Earth . Move the moon through one revolution around Earth . keeping Lincoln lace always looking at Earth . How many times did the penny make one complete rotation ?

Think Over Inferring From the point of view of someone on Earth , does the moon seem to rotate ?

Explain your answer . When you look up at the moon . you see what looks like it late . Some people call this thi man in What you are really seeing is a pattern of and att ' on surface that just to look like a lace . Oddly , this to . That is , the same side of the moon . the side . always laces . side of the moon always faces away from Earth . The reason has to do with how the moon moves in space . Motions of the Moon Like Earth , the moon through space in two ways . The moon around Earth and also on its own . As the moon revolves around Earth . the relative positions of the moon . Earth . and sun change . changing relative positions of the moon . Earth . and sun cause the phases of the moon , eclipses , and tides . The moon rotates once on its axis in the same amount of time as it ( Thus . at day and a year on the moon are the mine length . For this reason , the saint side of the moon always laces Earth . The length at the day is somewhat shorter than the days between consecutive full moons . This is because as the moon revolves around . Earth around the sun . Thus . the moon has to a little farther than one complete orbit between each full moon .

The same ?

of the moon always laces Earth . Phases of the Moon On ( lat night when thu moon is lull . thu bright tan you . But thu moon dons nut product light you see . Instead . it reflects light from the sun , flashlight dark mom . If you In shin Ant hair . uLl we the ' your would . or . ull the chair . III thu way that the ) would shim by ' moon give hy it , You can see the it reflects the light of the tun . we the in sky , slIm ( it round . yuu we only ' UI ' ul the moon you see are mulled . through uf time it ( Earth . Phasm ' caused by ' position 01 the , and the um . the sun lights the moon . half the moon is almost ' in sunlight . time the munn around lE . dill angles . The thu than faces ' nut . that . The phase of the moon you see depends on how much of the side of the moon faces Earth . Flaunt 10 The Moon in Motion The moon rotates on its axis and revolves around Earth in the same amount As a result . the near oi the moon ( shown with a flag ) always laces Earth . Interpreting Diagrams Would Earth ever appear to set below the horizon for someone standing next to the flag on the moon ?

Explain . 419 The Moon Seen From the Northern Hemisphere Waxing Yhe portion of the You can see half moon you can no is of side waning . or growing . of the moon . Into a crescent shape . New Moon Yhe sunlit side faces away from Earth . Waxing Gibbons The moon continues to wax . The sham of the moon I . View From Space Freon 11 Phases of the Moon The photos at the top of the page show how the phases of the moon appear when you look up at the moon from Earth surface . The diagram at the right shows how the Earth and moon would appear an observer as the moon revolves around Earths Interpreting Diagrams what phases are the moon , Earth , and aligned straight line ?

Third Quarter . Waning ( Moon Gibbons . Waning Gibbous . Crescent . First ( act ve For Phase and ( Visit . Web Code 4800 Full Moon The entire The portion of the You can see halt You see a crescent side laces Earth . moon you can see ! the moon once again . wanes . or shrinks . lighted side . To und tho ' at th , study I Du ring the new moon . the lit side or the moon from i . As . we and day , until ut the noun yuu ace in lit . in it . you we and lens uli . days after the last new moon , the cycle is complete . and new mom . The Moon Orbit ' The moon titted about degrees lo Earth around the Sun Eclipses . the orbit Earth is slightly Em , tilted with . In sum As . orbit in must months the moon without ing UI ( hitting . When the moon shadow Earth or Earth shadow hits the moon . an occurs . an in spun a between the sun and third , it nuts . on that , causing an eclipse ih take place . There are two I ) and lunar ( he and Latin ) 11 481

Solar Eclipse FIGURE 13 The outer layer of the sun atmosphere . the solar ( arena , is visible surrounding the dark disk of the much during a solar a solar . the moon blocks light from the sun , preventing sunlight from reaching parts of Earth . Making Models Here is how you can draw a scale model of a solar eclipse . The moon diameter is about one fourth Earth diameter . The distance from Earth to the moon is about 30 times diameter . Make a scale drawing of the moon . Earth . and the distance between them . Hint Draw Earth I ( in diameter in one corner of the paper . From the edges of the moon , draw and shade in a triangle just touching Earth to show the moon , 4820 When Do Solar Eclipses Occur ?

During it new . the Earth and the Run . But months , as you have seen . the moon travels at little above or below the sun in the sky , GA solar eclipse occurs when the moon passes directly between Earth and the sun . blocking sunlight from Earth . The . shadow their hits . as shown in 13 . So solar eclipse occurs when new moon your View of the sun . total Solar Eclipses Thu wry part at the ( the ( is any point in the , light from the sun is ' Il by the moon . The nimm ' to be long enough so that the point at the cone can lust reach part at . surface . within the a total . During the period . solar eclipse . the sky grows as dark as night . even in the middle til it day . The air gets cool and the sh an eerie color . You can see the stain and the solar , which is the faint outer of the sun . Partial Solar Eclipses In Figure . you can sec that the casts . part ) that is less than the , This larger part of the shadow is the penumbra . In thu . part of the sun is ' Earth . During 21 ( people in the only a partial eclipse . an bright part ul the sun still visible . it is not safe to look directly at the sun during partial solar eclipse as you would look directly itl the during a ( la )

Lunar Eclipse when Do Lunar Eclipses Occur ?

hiring . moon but not quite into it lunar eclipse zit xi lull moon is directly between the moon and the sun . You can see a lunar eclipse in During a lunar , Earth blocks sunlight from reaching the moon . The moon is then in Earth and looks dim Earth . lunar eclipses ur ' when is full moon because the is closest to Earth at that time . Total Lunar Eclipses Like moon in a . has an at . the entire moon is in umbra . you see total lunar . Yuu can i shadow inn and after total lunar ( a total eclipse , in total lunar eclipse can be seen on birth that is visible . So yuu art likely to see lunar eclipse than eclipse . Partial Lunar Eclipses For most lunar . the sun arr not quite in line . and only at lunar results . A partial lunar eclipse occurs when the moon passes partly into the of . of the . blurry , and yuu can watch it pass ' moon or two or hours . During phase of the moon ( an lunar eclipses , Flaunt 14 During a lunar eclipse . Earth blocks sunlight from the moon surface . The photo of the moon above was taken during a total lunar . The reddish lint occurs because atmosphere bends some sunlight toward the moon . Interpreting Diagrams Whatrs the difference between the umbra and the penumbra ?

for Mann Phases and Eclipses activity Visit ( Web ( 13 15 High and Low Tides In some locations . such as along this beach in Australia , there can be dramatic between the height of high and low tides . The moon gravity causes high tide on the side closest to the moon . 16 Gravity and Tides Tides occur mainly of differences in the force of gravity between the moon and different parts of Earth , Interpreting Diagrams when do high rides occur ?

4840 Tides Have you ever built a sand castle on an ocean beach ?

Was it washed away by rising water ?

This is an example of tides . the rise and fall of ocean water that occurs every hours or so . The water rises for about six hours , then falls for about six hours . in a regular cycle . The force of gravity pulls the moon and Earth ( including the water on surface ) toward each other . The tides are caused mainly by differences in how much the gravity pulls on parts of Earth . The Tide Look at Figure 16 . The force oi the gravity at point is closer to the moon . is stronger than the force of the moon gravity on Earth as a whole . The water flows toward point and high tide forms . The force of the moon ' gravity at point , which is on the far side of Earth from the moon . is weaker than the force of the gravity on Earth as a whole , Earth is pulled toward the moon more strongly than the water at point so the water is left behind . Water toward point , and a high tide occurs there too . Between points A and , water flows away from points and causing low tides . At any one time there are two places with high tides and two places with low tides on Earth . As Earth rotates , one high tide stays on the side oi Earth facing the moon . The second high tide stays on the opposite side of Earth . Each location on Earth sweeps through those two high tides and two low tides every 25 hours or so . Low tide low tides occur between the two high tides . Norm ' Pole tide The force of the moon gravity pulls toward the moon . leaving the water behind . Low tide

Spring Tides The sun gravity also pulls on man 17 waters . shown in the top diagram of Figure , the Stating and sun . moon , and Earth are nearly in a line during new ' a ' moon . The gravity of the sun and the moon pull in the am me man is gig , angle same direction . Their combined produce a ( a Map ( id , with the greatest difference between consecutive low and high tides , called at spring tide . At full moon , the moon and the sun are on opposite ' sides of Earth . Since there are high tides on both sides of Earth . a spring tide is also produced . It matter in which order the sun , Earth , and moon line up . Spring tides New moon occur twice a month . tit new moon and at full . Map Tides During the moon and phases . the line between Earth and the sun is at right angles to the line between Earth and the moon . The sun pull is at right angles to the moon pull . This arrangement produces at neap tide . a tide with the least difference between consecutive low and high tides Neap tides twice month . Whit is I tide ?

Section ' Target Reading Skill Sequence Create a cycle diagram with four phases of the moon new moon . first quarter . full moon . and third quarter . For each a sketch of how the moon looks . the ! use daily Reviewing Key Concepts newspaper or the Internet to track . I . Explaining What causes the to shine ?

Th ?

high and OW . Relating Cause and Effect does the moon appear ' he to change shape during the course of a month ?

data , with the date as the and tide height asthe . Also find the dates of the new moon and full moon and add them to your graph . Show your completed graph to a relative and explain what the graph shows . interpreting Diagrams Use Figure it to explain why you can ! see the moon at the lime Ulla new ' I ( MIT a . Explaining What is an eclipse ?

la . Comparing and Contrasting How is a solar eclipse from a lunar eclipse ?

Relating ( nose and Effect there solar eclipse and a lunar eclipse each month ?

Summarizing What causes the tides ?

Explaining Explain why most coastal regions have high tides and two tides each day . Comparing Ind ( the size of high and low tides in a spring tide and il neap tide . What causes the ?

A of Phases . I . Have your partner turn the left while keeping the ball in front and at arm length . Repeat Step . Be sure you are standing directly behind your partner . 10 . Repeat Steps and six more times until your partner is facing the lamp again . See Skills FOCUS the photograph for the positions , making models , observing , drawing conclusions 11 , change ( and repeat steps , Materials floor lamp with bulb pencils plastic foam balls Procedure . Place a lamp in the center of the room . Remove the lampshade . Close the doors and shades to darken the room , and switch on the lamp . Carefully stick the point ot a pencil into the plastic foam ball so that the pencil can be used as a . Draw circles on a sheet of paper . Number them . Have your partner hold the plastic foam ball at arm length in front and slightly above his or her head so that the ball is between him or her and the lamp . CAUTION Do not look directly at the bulbs . The ball should be about to away from the lamp . Adjust the distance between the ball and the lamp so that the light shines brightly on the ball . Stand directly behind your partner and observe what part oi the ball facing you is lit by the lamp . light is visible on the ball , draw the shape of the lighted partial the ball in the first circle . 4860

Analyze and conclude . Mailing Models In your model . what Earth ?

The sun ?

The moon ?

Observing Refer back to your circles . How much of the lighted part of the ball did you see when facing the lamp ?

Classifying Label your drawings with the names of the phases of the moon . Which drawing represents a full moon ?

A new moon ?

which represents a waxing i res ?

A waning crescent ?

Observing How much of the lighted part of the ball did you see after each turn ?

Drawing Conclusions Whether you could see it or not . how much ofthe hall lace was always lit by the lamp ?

Was the darkness of the new moon caused by an eclipse ?

Explain your answer . Communicating Write a brief analysis of this lab . How well did making a model help you understand the phases of the moon ! What are some disadvantages of using models ?

What is another way to make a model to represent the various phases of the moon ! More to Explore Design a model to lunar eclipse and a solar eclipse . What objects would you use for Earth , the sun , and the moon ?

Use the model to demonstrate why there is an eclipse every full moon and new moon .

Focus Students the appear once , general . relative position and size , and motion of objects in the solar system . ing planets . planetary satellites , comets . and asteroids . What features are found on the moon surface ?

what are some characteristics of the moon ?

How did the moon form ?

Key Terms I telescope I maria I crater I meteoroid Earth Moon Standards Why Do Craters Look Different From Each Other ?

The moon surface has pits in it , called craters . I . Put on your goggles . Fill a large plastic basin to a depth of with sand . Drop marbles of different masses from about 20 high . Take the marbles out and view the craters they created . Predict what will happen if you drop marbles from a higher point . Smooth out the sand . Now drop marbles of different masses from about So high . Take the marbles out and view the craters they left . Think It Over Developing Hypotheses In which step do you think the marbles were moving faster when they hit the sand ?

If objects hitting the moon caused ( how did the speeds of the objects affect the sizes of the craters ?

How did the masses of the objects affect the sizes of the craters ?

For thousands of years . people could sci shapes on the surface of the moon . but didn know what caused them . The ancient Greeks thought that the moon was smooth . It was not until about 400 years ago that scientists could study the moon more closely . In . the Italian scientist Galileo ( heard about a telescope . a device built to distant objects by making them appear closer . Galileo soon made his own telescope by putting two lenses in a wooden tube . The lenses focused the light coming through the tube . making distant objects closer . When Galileo pointed his at the moon , he was able to sci much more detail than anyone had ever seen before . What Galileo saw astounded him . Instead of the perfect sphere imagined by the Greeks . he saw that the moon has an irregular surface with a variety of remarkable features . Galileo used a telescope to help make this drawing of the moon .

The dark , lat areas on the moon surface are called marl The features that we much of the moon surface are highlands The Moon Surface Recent photos of the moon show much more detail than Galileo could see with his telescope . on the moon surface include maria , craters , and highlands . Marla The moon surface has dark , areas , which Galileo called maria ( MAH rec uh ) the Latin word for incorrectly thought that the maria were oceans . The maria are actually rock formed from huge lava that between and billion ago . Craters Galileo saw that the moon surface is marked by large round pits called craters . Sonic craters are hundreds of kilometers across . For a long time . many scientists mistakenly thought that these had been made by volcanoes . lists now know that those craters were caused by the impacts of , chunks of rock or dust from space . The maria have few craters compared to surrounding areas . This means that most of the moon craters formed from impacts early in its history . before the maria formed . On Earth . such ancient craters have disappeared . They were worn away over time by water , wind , and other forces . But since the moon has no liquid water or atmosphere . its surface has changed little for billions of years . Highlands Galileo correctly inferred that some of the colored features he saw on the moon were highlands . or mountains . The peaks of the lunar highlands and the rims of the craters cast dark shadows . which Galileo could see . The rugged lunar highlands cover much of the moon surface . I What an FIGURE II The Moon ! The moon surface is covered by craters . maria , and highlands . on the moon formed from the impact of meteoroids . Most large craters are named after famous scientists or philosophers Observing What are the light regions in the top photograph called ?

Go INKS , For Unto on Earth moon Visit Web Code items 19 The Moon Size The diameter moon a Mme loss than the sums the ( United Slates What I ! the ratio of the moon diameter to the ( between Earth and the moon ?

Plan 20 The Mount surface This photo of a large boulder field and hills on the moon , was by . arm ' Characteristics of the Moon ( Age 01 about kilometers 30 lime . in space . Despite its . the moon is very from . The moon is dry and airless . to Earth , the moon is small and has large variations in its surface . yuu ( would need In mil to an In . protect , In ' Size and Density The in , Ihr ( Ins . unly mu as an . wry win , its Ins ia Lu ( of . Temperature and Atmosphere On the moon . in dim ! In it frigid ( night . un munn xu much il ins no ( il ) I iJ ) span Water has in liquid . ix that than bu large of ice near the pulu . min ' in thew are an low that ice there remain If built ( in the . any ix . It would he amount In Reading Where on the moon is there evidence oi the of ice ?

The Origin of the Moon ' Formation Moon People have long wondered how the moon . Scientists to me ( have suggested possible . or . vim theory . the early In the moon formed elsewhere in the solar system and captured ' i ax it ' near ?

an the mum near Obie ?

mud The I debris formed the moon . at the time that formed ?

Scientists have reasons to these ideas . The theory of the moon origin that seems In best til the evidence is called the theory . It is illustrated in Figure . About ago . when Earth was very young . the solar was full if rucky debris . Same of this Em , Moon , sun debris the size of small Scientists theorize that a object collided with Earth to form the moon . Material tram the and Earth outer ' was ejected into orbit around Earth , where it El ring . Gravity this to combine to the . section Assessment Vocabulary Skill Latin Word Origins ( Relating Cause and What is the ' Why did ( word lor relationship the this feature iii the ?

Due the Latin origin . lad of an atmosphere . and of thi ( ribe what scientists range ?

know about the ?

Why or not ?

be ) the muon ?

wax like I when the ?

Reviewing Key Concepts features the su . th I I . HINT Explaining How did the ( hey , Relating Cause and Why is the much heavily ' than Earth surface ?

ty ' I a . Describing ) the range of ) un the . and Contrasting ( Earth and the moon Ill lo . of size and an . With an adult , observe the moon a few days alter the phase . Make a sketch of the features you see . Label the mana . and highlands .

Chapter 12 Study Guide The motions ol Earth and the moon and their position relative to the ' sun result in day and night . the seasons . phases of the moon , and tides . 11 Earth in Space Key ( I move space in major ) ils axis is tilted around Key Terms Al ( calendar equinox Gravity and Motion ( Key Concepts The ! lhe two objects depends on factors the and Ill . two keep Earth orbit around the and munn in Key Terms lune gravity ' 111 weight 491 Phases . Eclipses . and Tides Key Concepts , arm I The changing . and sun came the uf the eclipses . and rides . a The phase of the 11111 how ul ( the 1119011 ' hits Earth ur Earth hits the . an . I A tulip ) passes and the sun , During 11 lunar . Earth block sunlight from . are how much the moon ' pull on uf . Key Terms phase lunar eclipse lid spring lid neap ride Earth Moon ( Key Concepts I , moon dry and . small and has law ' in 111 ( Scientists that a object collided with I ( Key Up ' cram

Target Reading Skill Go II ! For ( Web ( ode ( Review and Assessment Phases of the Moon Sequence Draw 41 cycle diagram ( or the phases of the . the phase ) in which a could ( ur . Reviewing Key Terms Choose the letter of the best answer . Complete the following sentences so that . The of um um you dearly explain the key 31 is ' revolution . at . lIlt ) in about 365 IM ' Universal Law Gravitation slam INT . A day when the Hill its that ' or south the A 50 ' ups mun ! Thu ( ul the and sun . I . mix . the height the tides . arc lhe ) an to notion i , 10 . he moon by craters Emmy because lIlt . force , In the I aw ( lions Report Imagine that you are a . When Earth on the . A asked to story the . of the moon . Write an article . explaining how the moon formed . full . lunar . The crater tun were caused It nde and Saul ' mean , and sun . Chapter 12 493

Review and Assessment length year are , 12 . Suppose you two apart . would ?

in your . 14 ( haw ?

15 . Why do more people see total than ?

16 . Why is there high tide on the side or the ?

the side ( furthest frum the moon ?

17 . Dun the below spring lid neap tide ?

How do know ?

did the ( II the contribute to our knowledge the ?

19 . Why do temperatures vai so im the ?

think the moon . thinking Cri ( the same angle ) your , 22 , Comparing and Contrasting How are mass and ?

23 . 450 100 Ull . would weigh on ?

494 10 . Applying Concepts . time the lull ?

it ' in eastern sky or the western sky ?

25 . Posing Questions mu to ) to wear un the moon ( moon would he in design ?

Applying Skills Use the illustration below to answer Questions . Sun rays Equator 26 . Interpreting Diagrams On ) are the surfs I ) lalling must directly ?

27 . Inferring In the is the ( winter ) inc ill ?

How do know ?

18 . Predicting Six alter this . will have revolved around the sun . I A and ( Earth axis will be tilted the sun . Standards Investigation Assessment Present your lug , and of . Sums way to graph your data time of fur how ' moon In each direction or how often you saw the at a . graphs . us any that you .

Standards Practice Choose the letter of the host answer . I . You observe a thin crescent moon in the western sky during the early evening . About two weeks later , a full moon is visible in the eastern sky during the early evening . Which conclusion is best supported by these observations ?

A The moon revolves around Earth . I The moon rotates on its axis . revolves the sun . Earth is tilted relative to the . Only one side moon is visible from Earth because A the moon does not rotate on in axis . I the moon does not revolve around Earth . the moon rotates faster than it . the moon revolves once and rotates once in the period . What type of eclipse occurs when covers the moon ?

A a partial solar eclipse I a total solar eclipse I a partial lunar eclipse a total lunar eclipse . The force depends on A mass and weight . I speed and distance . mass and distance . weight and speed . The craters on the moon were caused by A tides . volcanoes . meteoroids . maria . this . You can see the moon at night because A the moon produces its own light . I the moon light from the sun . the moon light produced on . the near side of the moon always faces the sun . Success it Tracker Order at The diagram below shows tha relative positions of the sun . moon . and Earth . the numbers indicate specific locations of the moon in its orbit . Use the diagram to Questions . Which of the following can occur when the moon is at location I ?

A only a lunar eclipse I ! only a solar eclipse ( I both solar and a lunar eclipse neither a solar not a lunar eclipse . When the moon is at location at most coastal locations there would be A only one high tide each day . only one low tide each day . two high tides and tides each clay . with the most difference between high and low tide . two high tides and two low tides each day . with the least between high and low tide . When the moon is in location a person standing on Earth at night would see A a full moon . a crescent moon . a quarter moon . a new moon . what ways do Earth and the moon move through space ?

How do these motions produce such phenomena as day and night , the seasons . phases of the moon . and eclipses ?