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Earth Science Chapters 10 & 11 Chapter 10- Earth & Its Moon Lesson 1- Earth’s Seasons Objective- In this lesson, we will learn how the Tilt (position) of the Earth’s Axis will cause seasons Earth’s Tilted Axis Earth rotates constantly on its axis It takes almost 24 hours for Earth to make a complete rotation on its axis (equal to one day) As Earth spins, different parts of it face and turn away from the Sun. This creates day and night As Earth spins on its axis, it also revolves around the Sun. One full trip around the Sun is a Revolution It takes about 365 days, or 1 yr. Earth’s orbit is in an ellipse shape Because of Earth’s tilted axis, some areas experience severe seasons, while others (near equator) do not. Solstices There are two solstices throughout the year. Winter Solstice- December 21 or 22 First day of Winter Least amount of daylight all year Summer Solstice- June 21 or 22 Beginning of summer in N. Hemisphere Longest amount of daylight all year Equinoxes- Periods of daylight are equal Autumnal EquinoxSeptember 22 or 23 First day of Fall Vernal Equinox March 20 or 21 First day of Spring Seasons All places on Earth have four seasons. Places near the Poles have lower average temperatures than places near the Equator This is caused by amount of sunlight the area receives Lesson 2- Earth’s Moon The Moon • The moon is a natural satellite that revolves around the Earth • It is ¼ the size of Earth • Mass is 80 times lighter than Earth’s • It has less gravity than Earth Viewing the Moon The moon seems so large because it is closest to Earth than any other object in space. ( it’s actually smaller than Earth) Moon doesn’t produce any light. Sun reflects light off its surface Moon revolves around Earth, while it rotates on an axis. Takes 27 and 1/3 days to revolve, and rotate once around Earth. Same side of the Moon ALWAYS faces the Earth. Phases of the Moon One side of the Moon (half) is always lit by the Sun. The different shapes created by the visible light are Moon Phases Different parts of the Moon’s lit side are visible on Earth Takes about one month to complete one Moon phase cycle. Phases of the Moon New Moon- the Moon is between Earth and the Sun. Because its lighted side is facing away from Earth, the Moon appears dark when viewed from Earth. Waxing Crescentappears after the new Moon phase. The sunlit portion is increasing, but less than half. The first quarter and third quarter moons (both often called a "half moon"), happen when the moon is at a 90 degree angle with respect to the Earth and Sun. So we are seeing exactly half of the moon illuminated and half in shadow. Waxing Gibbous- After the first quarter, the sunlit portion is still increasing, but now it is more than half. At a full moon, the Earth, Moon, and Sun are in approximate alignment, just as the new moon, but the moon is on the opposite side of the earth, so the entire sunlit part of the moon is facing us. The shadowed portion is entirely hidden from view. http://www.moonconnection.com/moon_phases_calenda r.phtml Waning Gibbous- After the full moon (maximum illumination), the light continually decreases. Following the third quarter is the waning crescent, which decreases until the light is completely gone -- a new moon. Eclipses An Eclipse occurs when one object passes into the shadow of another object In order for one to occur, Earth, Sun and the Moon must all be aligned During a Total Eclipse, two types of shadows form Umbra- smaller, darker area, in Penumbra Penumbra- Larger, lighter area Solar Eclipse Occurs when the moon passes between the Sun and Earth Moon casts a shadow on Earth During the Day Moon blocks out the sunlight. Sun appears Black Lunar Eclipse Takes place when the Earth passes directly between the Sun and Moon. Moon moves into Earth’s shadow Occurs at night/dusk Moon appears to be a reddish color Chapter 11- Exploring Space Lesson 1- The Solar System The Sun and Its Neighbors The Sun and the bodies that orbit around it make up the solar system. Sun is largest in solar system Earth is one of eight planets in the solar system. Scientists believe that the solar system is about 4.6 billion years old. The strong gravitational force of the Sun holds all other objects in their orbits. Moons There are about 140 moons in the solar system. Some moons have their own atmosphere, unlike Earth’s moon. All are held in orbit by the gravity of their planet. Asteroids A small rocky object that orbits the Sun. Most are in a band between Jupiter and Mars, called the asteroid belt. There are many theories about how asteroids formed. Comets Small bodies made of dust, ice and frozen gases. Orbit the Sun in long elliptical orbits. A Coma is a glowing region formed from gases and dust of frozen solids. Tail of a comet always faces away from the Sun. Famous Comets Halley’s Comet- shortperiod comet that orbits the Sun about every 76 years. Visible from Earth again in 2061 Hale-Bopp CometLong-period comet, takes about 2500 years to orbit the Sun. Meteors and Meteorites Meteors are small chunks of matter that enter into Earth’s atmosphere Most burn up in the atmosphere, never striking Earth When many are visible at once, this is called a Meteor shower A meteor that does strike Earth is called a Meteorite When large ones strike Earth, they form impact craters Lesson 2- What are the Planets Like? The Inner Planets Inner Planets are rocky and small There are 4 inner planets Mercury- smallest and closest to the Sun. Side facing the Sun is very hot, facing away from the sun is very cold. Many craters on the surface Venus Venus- is the second planet from the Sun Thick atmosphere of clouds made of sulfuric acid. Hot temperatures on surface Extreme atmospheric pressure Earth Earth- 3rd planet from the Sun Only planet known to have liquid water Atmosphere and oceans make it the only planet in solar system known to support life Mars Mars- 4th planet from the Sun Known as the Red Planet Smaller than Earth but same amount of land area. Home to largest volcano in the solar system Planet most like Earth Most explored planet, Mars Expedition Rovers Outer Planets There are four outer planets Most are huge and made of gases They have many moons and one or more rings. Pluto (dwarf planet) is the only exception Jupiter 5th planet from the Sun, and one of the brightest objects in the sky Biggest and most massive planet in the solar system Famous for its Great Red Spot, a gigantic storm system More than 60 moons. Saturn 6th planet from the Sun Best known for its rings, mostly made of ice particles Least dense of all planets Holds more than 30 moons in its orbit Uranus 7th planet from the Sun Axis is tilted so much, it looks like it on its side Consists mostly of gases 11 rings, and 27 moons High amount of methane give it the greenish color Neptune 8th planet from the Sun Has 11 moons, Largest moon is Triton Neptune is getting closer to Triton, and will probably collide in the next 100 million yrs. Coldest surface in the solar system Pluto Farthest from the Sun Recently (2006) discovered as a Dwarf Planet Very cold Has one moon called Charon Unlike other outer planets: Small, icy, rocky Exploring Space Optical telescopes are used to explore solar system The space shuttle takes equipment and people into space Space stations stay in space for long periods of time, astronauts can live, sleep and conduct experiments Space Probe- spacecraft that carries special instruments into space launched into Earth’s upper atmosphere Mars Rover- explored Mars, taking pictures and samples Lesson 3- What Are Stars Like? Earth’s Star: the Sun Star- large sphere of glowing gases Defined by its size and temperature Sun is a yellow star made mostly of hydrogen and helium A light-year (Ly)- used to measure outside of the solar system Distance light travels in about 1 yr. Magnitude- brightness of a star Stars closer to Earth appear brighter Constellations- arranged patterns of stars Big Dipper A Star is Born Stars begin as rotating clouds of gas called nebulas Cloud rotates faster and forms first stage to a star called a protostar Main Sequence star- continues to release energy, w/ nuclear reactions Hottest, brightest stars are blue or white in color Medium sized are yellow or orange Dimmest and coolest are Red. Sun is a medium star, halfway through its life cycle Red Giant Phase- after a main sequence White Dwarf phase a. Medium sized stars move here b. Beginning of dying stage, starts to run out of “fuel” c. Becomes a black dwarf- star that gives off NO LIGHT Supernova a. A very massive star that will explode from its center. o Larger remnants will become a Black hole i. powerful gravitational pull, and collapses onto itself o Smaller masses will become a Neutron star i. dense, rapidly spinning star Galaxies Enormous system of gases, dust and stars held together by gravity Most stars have 2 main partsBulge Halo Milky Way Galaxy of our solar system Spiral Galaxy More than 200 billion stars Types of Galaxies Spiral Galaxy- has a bulge, disk and halo, and arms that extend Elliptical Galaxy Shaped like a flattened ball Brighter in the center Irregular Galaxies no real shape or structure large regions of hydrogen gas and hot star