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1、www.readinga-Written by David L.DreierLEVELED BOOK VEclipsesEclipsesA Reading AZ Level V Leveled BookWord Count:1,589Visit www.readinga- for thousands of books and materials.EclipsesLevel V Leveled Book Learning AZWritten by David L.DreierIllustrated by Craig FrederickAll rights reserved.www.reading
2、a-CorrelationLEVEL VR4040Fountas&PinnellReading RecoveryDRAWritten by David L.Dreierwww.readinga-EclipsesPhoto Credits:Front cover,page 13(top):iS cover:Frank Zullo/Photo Researchers,Inc.;title page:Roger Ressmeyer/Corbis;page 3:REUTERS/Andrew Biraj;page 4:Joe Petersburger/National Geographic Stock;
3、page 5:REUTERS/David Gray;pages 7(left),9(top left):courtesy of ESA/NASA/SOHO;page 6:Signe Nordin/Learning AZ;pages 7(center),9(top center),13(bottom left):iS Rysavy;pages 7(right),9(top right),13(bottom right):courtesy of NASA;page 8:iS Putchenko;pages 9(bottom),10:iS Tuchan;page 11:Jim Craigmyle/C
4、orbis;page 12:Jay Pasachoff/Science Faction/Corbis;page 14:Astrofoto/Peter Arnold Images/Photolibrary;page 15:Centre National dEtudes Spatiales/NASA;page 16:World History Archive/Alamy Images;page 17:Jean-Leon Huens/National Geographic Stock;page 18:Mohammed Zaatari/AP Images;page 20:REUTERS/Russell
5、 Boyce;page 21:NASAHubble Space Telescope/Science Faction/Corbis;pages 2223:Larry Landolfi/Photo Researchers,Inc.Back cover:Composite photo of an annular solar eclipse over Franklin Mountains State Park near El Paso,TexasTitle page:A total solar eclipse in the sky over the W.M.Keck Observatory in Ha
6、waiiEclipses Level V34Table of ContentsDarkness at Noon or Midnight .4Eclipses in History .5Eclipses Are All About Shadows.7Why the Moon Turns Red .8The Sun Blotted Out .12Predicting Eclipses .16How to View a Solar Eclipse Safely.18Conclusion.21Glossary.24A girl prepares to watch a solar eclipse in
7、Bangladesh.Darkness at Noon or Midnight Imagine being outside on a sunny day at noon and seeing the world become dark all around you,even though theres not a single cloud in the sky.Or imagine watching a full moon slowly change from milky white to a spooky blood-red color.Strange events such as thes
8、e happen during eclipses.Eclipses are amazing events that have caused wonder,fear,and excitement throughout history.During a solar eclipse,the Moon blocks out the Sun.During a lunar eclipse,the Moon changes color as it passes through Earths shadow.The Moon blocks part of the setting Sun during a sol
9、ar eclipse.Eclipses Level V56Some eclipses may even have changed the course of history.One such event occurred in the Middle East in the sixth century bc.Two groups of people,the Lydians and the Medes,had been fighting a war for five years.On May 28,585 bc,their armies were engaged in a fierce battl
10、e when suddenly a total eclipse turned day into night.The armies were so frightened by the eclipse that they laid down their weapons and agreed to make peace.Ancient peoples such as the Chinese,Greeks,Babylonians,and Egyptians studied eclipses.They eventually learned that eclipses were natural event
11、s.There were no dragons or other monsters involved.However,knowledge about what really caused eclipses spread slowly.Eclipses in History Eclipses can be frightening events if you dont know what causes them.Long ago,people were afraid of eclipses and considered them to be bad omens.People in ancient
12、China thought the Sun was being eaten by a dragon during a solar eclipse.They banged on drums and pots to scare the dragon away.Some ancient people in Greece thought there might be a connection between earthquakes and eclipses.But there is no link between the two events.A solar eclipse darkens the d
13、aytime sky over China.Eclipses Level V78Earths atmosphere filters and scatters some of the sunlight that passes through it.Why the Moon Turns RedIf Earth had no atmosphere,the Moon would go completely dark during a total lunar eclipse.But Earth does have an atmosphere,and light from the Sun passes t
14、hrough it.Most of that light strikes Earths surface and is blocked.But some light rays pass through the atmosphere without hitting the planets surface.Eclipses Are All About ShadowsWe now know that eclipses happen when Earth,its moon,and the Sun line up in space.An eclipse is nothing more than a rea
15、lly big shadow.Just as you cast a shadow on the ground when you stand outside on a sunny day,Earth and its moon cast shadows in space.What an eclipse looks like depends on where you watch it from.If you were standing on the surface of the Moon during a lunar eclipse,you would see the Earth ringed by
16、 red light as it blocked out the Sun.But from Earth,a lunar eclipse looks much different.If you watch a lunar eclipse from Earth,you will see the full moon slowly go dark as it passes through Earths shadow.Thats because the Moon is only bright when it reflects the light of the Sunsomething it cant d
17、o when Earth gets in the way.MoonEarthEarths shadowPositions of the Sun,Earth,and Moon during a lunar eclipseSunEclipses Level V910The Moons changing appearance during the course of a lunar eclipseThe Suns light is made up of many colors that blend together to form white light.The atmosphere absorbs
18、 most of the blue light in the Suns rays.But red light passes through the atmosphere and is scattered before passing back out into space.Some of that light strikes the Moon and gives it a spooky appearance.The Moon usually turns a reddish color,but it can also be orange,yellow,or brown.The color dep
19、ends on the amount of dust and clouds in Earths atmosphere.A total lunar eclipse turns the Moon a dramatic red color.Some red light from the Sun bends as it passes through Earths atmosphere and reaches the Moon,turning it red.Red light scattered by Earths atmosphereMoonEarthAtmosphereEarths shadowSu
20、nEclipses Level V1112Total lunar eclipses happen fairly frequently.There can be as many as three in a year.But in some years,there are none.It all depends on the changing positions of the Moon and Earth.And because lunar eclipses are visible from the entire side of Earth where its nighttime,you will
21、 probably have many chances to see one near where you live.Lunar eclipses are perfectly safe to watch and can be safely viewed through binoculars or telescopes.The length of time that the Moon is in full shadow during a total eclipse varies anywhere from about thirty minutes to more than an hour.A t
22、elescope can give you a great view of a lunar eclipse.The Sun Blotted Out The other type of eclipse is a solar eclipse.During a solar eclipse,the positions of the Moon and Earth are just the opposite of their positions during a lunar eclipse.The Sun is about four hundred times larger than the Moon,b
23、ut it is also about four hundred times as far away from Earth.This happy coincidence of nature means that,seen from Earth,the circular disk of the Moon is just the right size to block out the Sun.When the Moon blocks the light from the main part of the Sun,the Suns outer part,called the corona,becom
24、es visible.The hot gases of the corona glow brightly around the obscured disk of the Sun.The hot gases of the Suns corona are easy to see when the Moon blocks out the Sun.Eclipses Level V1314Because the Moons orbit around Earth is not a perfect circle,the Moons distance from Earth changes.When the M
25、oon is farther away,it appears slightly smaller and does not completely block out the Sun during an eclipse.The Suns disk then forms a narrow ring around the Moon.This is called an annular eclipse.Annular comes from the Latin word meaning“ring.”The length of a total solar eclipse varies from one ecl
26、ipse to another and also depends on where you view it from.The longest time that people can see the Sun totally darkened is about seven and a half minutes.An annular eclipse creates a bright ring of light around the Moon.During a solar eclipse,the Moon casts a double shadow on Earth.People inside th
27、e dark center shadow see a total eclipse,in which the entire disk of the Sun is blocked for a short time.Inside the lighter outer shadow,part of the Suns disk is still visible during a partial eclipse.Beyond the lighter shadow,people see no eclipse at all.Dark shadow,area of total eclipseLight shado
28、w,area of partial eclipseSunlightMoonEarthPath where total solar eclipse can be seen as it moves across EarthEclipses Level V1516People have far fewer chances to see solar eclipses than lunar eclipses.Solar eclipses happen in one form or another somewhere on Earth about once every eighteen months.Ho
29、wever,many solar eclipses occur over open oceans or in the polar regions,so very few people get to see them.Also,because the Moons darker center shadow on Earth is never more than 269 kilometers (167 mi)wide,the chance of your area being in the path of a total eclipse is very small.Each particular s
30、pot on Earth experiences a total solar eclipse just once every 370 years,on average.For that reason,if you want to see a total solar eclipse,it is much better to travel to where you know one will happen than to wait for one to come to you.But how can you tell when and where the next solar eclipse wi
31、ll happen?The Moons shadow can be seen from space as it passes across Earths surface during a solar eclipse.Predicting Eclipses Astronomers have tried to predict eclipses since ancient times.Many astronomers in ages past kept careful records of eclipses.They learned that eclipses happen in a long cy
32、cle.They also studied how the Moon moves around Earth.Their findings helped them predict lunar eclipses with some accuracy.But figuring out when solar eclipses would happen was much more difficult.By about 1,800 years ago,astronomers in China and Greece had learned to predict solar eclipses.One of t
33、he most famous of these astronomers was a Greek named Ptolemy(TAWL-uh-mee).But Ptolemy and other ancient astronomers could only predict a solar eclipse to within about a month.Ptolemy was a famous mathematician and astronomer who lived around ad 90168.Eclipses Level V1718The first scientist to accur
34、ately predict solar eclipses was an English astronomer named Edmond Halley.During his lifetime in the early ad 1700s,people knew that Earth orbited the Sun.Knowing the correct positions of the Sun,Earth,and Moon made eclipse prediction simpler.But it was still difficult.Another English scientist,Isa
35、ac Newton,made it easier to predict eclipses.Newton discovered how objects in the solar system move.He developed a very detailed theory of gravity.Halley used Newtons findings to calculate future eclipses.By using computers programmed with Newtons laws of gravity,scientists can now predict eclipses
36、far into the future.Isaac Newtons ideas about gravity and mathematics changed our understanding of the universe.How to View a Solar Eclipse SafelyOnce youve figured out where you need to be to see a solar eclipse,your work is not quite done.You need to take some steps to make sure you can watch the
37、eclipse safely because looking directly at the Sun can damage your eyes.Normally,the Sun is too bright to look at for very long,and pain makes you look away.But during an eclipse,the brightness dims,and its possible to look at the Sun without feeling any pain,even while severely damaging your eyes.F
38、or this reason,you should NEVER look directly at the Sun during an eclipse or at any other time.A shepherd boy and his goat watch a solar eclipse in Lebanon.Eclipses Level V1920The safest way to view a solar eclipse is indirectly,using a pinhole projector.This simple device focuses the Suns rays ont
39、o a flat surface,where they can be viewed safely.WarningDo not view a solar eclipse with unprotected eyes or regular sunglasses,and never look at a solar eclipse with a telescope or binoculars.Devices that magnify what youre looking at will also magnify the damage done to your eyes.Small image of pa
40、rtially eclipsed SunWhite paper taped to inside endViewing windowPoint this end toward SunPinhole ProjectorAluminum foil with pinholeLook through hole cut in side of box to see eclipse image SunlightIt also is possible to view a solar eclipse safely using special light filters,such as inexpensive ec
41、lipse-viewing safety glasses.Even when using these special glasses,you shouldnt look at the Sun for very long.Look for a few seconds and then turn away for a few seconds.Be sure to use these glasses only in the company of an adult.You cant be too careful when looking at the Sun.A crowd practices usi
42、ng protective glasses before an eclipse in the United Kingdom in 1999.Eclipses Level V2122ConclusionEclipses are impressive cosmic events that still inspire awe in people of all ages around the world.Thanks to science,we now understand the causes of eclipses and can predict them with amazing accurac
43、y.But eclipses will probably always feel a little mysterious and magical to those who watch them,just as they did to people thousands of years ago.A small moon casts a shadow on the surface of Jupiter as it orbits the giant planet.This special photograph shows how the Moon looked every five minutes
44、during a lunar eclipse over upstate New York.Eclipses Level V2324Glossaryaccuracy(n.)the state or quality of being precise,correct,or exact(p.16)astronomers(n.)scientists who study planets,stars,galaxies,and other objects in space(p.16)coincidence(n.)a situation in which similar or related things ha
45、ppen at the same time by accident(p.12)cosmic(adj.)of or relating to the space beyond Earth(p.21)light filters(n.)transparent materials that block light of certain wavelengths (p.20)obscured(adj.)concealed or covered(p.12)omens(n.)events believed to be signs about the future(p.5)orbited(v.)revolved
46、around another object(p.17)partial(adj.)of or relating to a part rather than the whole(p.13)predict(v.)to say what is going to happen in the future,based on the past or present(p.16)theory(n.)a possible explanation that has not been proven true(p.17)To learn more about eclipses and find out when you can view one in your area,go to http:/eclipse.gsfc.nasa.gov/eclipse.html.