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Unit 2 Earth, Moon, Sun Key Words. Aphelion Terrestial Motion Isoline Solstice Equinox Gradient Contour Line Mean Solar Day Topography Azimuth Analemma Foucault Pendulum. Axis of Rotation Revolution Eccentricity Kepler’s Law Galileo’s Ideas Latitude Longitude Field
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Unit 2 Earth, Moon, SunKey Words • Aphelion • Terrestial Motion • Isoline • Solstice • Equinox • Gradient • Contour Line • Mean Solar Day • Topography • Azimuth • Analemma • Foucault Pendulum • Axis of Rotation • Revolution • Eccentricity • Kepler’s Law • Galileo’s Ideas • Latitude • Longitude • Field • Oblate Spheriod • Heliocentric Model • Altitude • Coriolis Effect
The earth’s movement around the sun. • Revolution: The action of a celestial object of going around in an orbit or elliptical course. 1. in ellipse pattern (a slightly squashed circle. 2. One revolution took 365 days
How did scientists discover that the earth revolves around the sun? • Galileo’s Ideas: (1564-1642) • 1. believed planets revolve around the sun in circle • 2.Discover the telescope: Discover 4 moons revolves around Jupiters. • 3.The moon is not a smooth sphere. • 4. The sun has sun spots which means that it rotates.
Scientists’ theory of the earth 1. Claudius Ptolemy (Alexandria 90-168) suggested the Geocentric Model where other celestial bodies moved around the earth. 2.Nicolaus Coppernicus (Poland 1473-1543) proposed that the sun is stationary and other planets revolve around it. Heliocentric Model: The sun is the center. 3. JohanneKeppler (German 1571-1630) perfected it but said orbits are ellipse. This model is better than Ptolemy’s geocentric model. 4.Galilei Galileo (Italy 1564-1642) created the telescope. “Father of Modern Science. Championed the heliocentric Model
What happens when the earth moves around the sun? • Kepler’s Law: Johanne Kepler (1561-1630) • 1.Orbit of a planet around the sun is elliptical • 2. In an ellipse, the planets move faster when they are near the sun and slower when they are far from the sun. • Area 1 = Area 2 • Time 1 = Time 2 • Distance 1 Distance2 • 3. The orbital period of revolution of planets and their distances to the sun are proportional. Distance is A.U. • Period of revolution2= distance3 • 4. The earth moves in an elliptical pattern and at different speed due to gravity of the sun its centrifugal force (the force that makes a body follow a curve path)
Eccentricty • Eccentricity: The deviation of the path of an orbiting body from a true circle. It is an elliptical orbit. The eccentricity is a relationship between the distance between the foci and the length of the major axis is the orbit • d • ___length_ • Eccentricity = d/ length • If Eccentricity=0 then it path is a circle • If Eccentricity= 1 then the path is a straight line • If Eccentricity is between o and 1 then it is an ellipse
Calculation of the revolution of planets around the sun 1Mercury is .39 AU from the sun . How big is its revolution around the sun in earth year From Period of revolution2= distance3 , it would take .24 year or 3months 2. Venus is .72 AU from the sun. How big is is revolution? Period of revolution2= distance3 it would take .61 year or over 7 months 3 Mars has a period of 1.88 year for every revolution around the sun. How far it is ? • From Period of revolution2= distance3 A.U distance would be 1.52 4. Jupiter is 5.2 A.U from the sun. How big is its revolution • 11.9 earth years 5. Saturn is 9.59 A.U. 29.7 earth year 6. Uranus revolution is 84.12 earth year. How far it is from the sun Uranus 19.2 AU 7.Neptune revolution is 165.13 earth years. How far it is from the sun? Nepture 30.1 AU 8. Pluto 39.5 AU what is its revolution? Pluto 248.25 earth years
Earth and Magnetic Field • 1. One of the liquid outer core of the earth is a molten iron and nickel metals • 2. As a consequence, these metals make earth behaves as if it is a giant bar of magnet • 3. Magnetic reversal: • after a period of time, • the earth magnetic field reverses. • North becomes South and • vice versa
Earth and Magnetic Field (Cont.2) Interactive 1 • 1. What creates Earth’s Magnetic Field? • 2. What happens to the intensity and direction of the magnetic field according to the computer model? • 3. What was studied in Oregon? • 4. What has been happening over the past 300 years? • 5. How often has the magnetic field reversed, according to the research? • 6. How long has it been since the last reversal? • 7. How long does a reversal take to complete? • http://www.pbs.org/wgbh/nova/earth/when-our-magnetic-field-flips.html
Foucault Foucault Pendulum: It is a type of pendulum created in 1851 to prove of the earth’s rotation. The rate of change in a Foucault Pendulum depends on the latitude of the site. At the north pole, the rate of change is 150 / hour, which mean in 24 hours it would make a circle or rotates 360 degree. At any other latitude it changes from 00 to 150 degree, at the equator, the pendulum does not change. In the northern hemisphere it shifts clock wise, in the southern hemisphere it shifts counter-clockwise.
The earth rotates on its own axis 1 Axis of Rotation: An imaginary straight line around which an object such as the earth rotates. (The foucalt’s pendulum works because of the rotation of the earth, which we called it apparent motion) The axis of earth rotation is tilted by 23.50 We know this because of the position of the stars in celestial bodies appears to revolve around the North Star as the earth revolve around the sun. 2. Because of the (Oblate Spheriod: Flattened sphere which bulging at the equator and slightly flattened at the poles. This effect is due to gravitational pull of the earth toward the center. Length 12, 714 km, Diameter: 12,754 km.) shape of the earth The earth rotates at 1,700km/hr at the equator while at the north pole it is almost nothing
Interactive 2 Answer these questions: 1.Why does the Earth spins? 2. Why has the Earth’s spin slow? 3. What will happen to the moon? http://www.ck12.org/flx/render/embeddedobject/1480
IntErACtIVE 4. How long does it take for the Earth to complete a rotation? 5. What direction is the Earth rotating?
Coriolis Effect • Because of the rotation of the earth, counter clockwise (sun rise in the east, and set in the west) it affect the wind and ocean currents. • In the northern hemisphere, the currents clockwise, and in southern hemisphere counter-clockwise.
Earth’s Revolution around the sun • Terrestial Motion: motion of the earth, as it rotates around its axis, revolves around the sun, in relationship to the solar system as it rotates in the Milky Way galaxy, and of the relationship of the Milky Way galaxy to other galaxies. • (Motion is inertia that is moving in a straight line as in projectile, unless other forces act on it as in a pendulum. The forces acting on an object causes it to move in a circular motion as in centrifugal force- moving away, centripetal force-moving toward the axis.)
Earth’s Revolution around the Sun (cont3) • Analemma: A plot or graph of the position of the sun measured at a certain time of day, (usually at noon) throughout the year. It has a shape of an 8. This is due to the tilting of the earth axis as it revolves around the sun. The farthest north and south are the Tropic of Cancer 230 north and the Tropic of Capricon 230 south respectively. • Solstice: The time when the midday sun is directly overhead at one of the tropic latitude. June 22, the sun is over 23.50 north in the tropic of Cancer, and December 21 at 23.50 south in the tropic of Capricorn. (See map) • Equinox: The two points in the elliptical revolution of the earth around the sun, where sun intercept the earth’s equator, such that the sun is directly over the equator. At the equinox, everywhere on earth will have 12 hours of sun light and 12 hours of night. It happens on March 21, and Sept 21. (See map)
PeriHelion and APHEliON • Aphelion: The point farthest from the sun in the orbit of a planet or comet. The farthest is when the velocity of the object is slowest (around July 4, 94.5million miles, and fastest when it is closest to the sun (perihelion, Jan 3, 91.5 million miles)
SeASons • Summer and Winter are not due to how close the planet earth is closest to the Sun. Rather it is due to the tiltation of the earth as it revolves around the sun. • On June 21, 23. The tiltation of the earth 23.5 degree point North Latitude (Tropic of Cancer directly at the sun, thus the sun ray covers most of the northern hemisphere. We have northern hemisphere summer, but southern hemisphere is in winter. • On December 21, 22 the sun shown directly on the 23.5 South Latitude (Tropic of Capricorn. Result the southern hemisphere is in summer while the northern hemisphere is in winter.
InterACTive # 3 Season 1.What causes Earth’s seasons? 2.What is the longest day of the year in the Northern Hemisphere? 3.What occurs at the equinoxes? 4.What happens during the winter solstice? 5.When is summer in the Southern Hemisphere? http://www.learner.org/jnorth/tm/mclass/eclipticsimulator.swf 6.Place the observer on the Tropic of Capricorn and run the animation. When does the observer get the most direct sun light (90 degree angle)? 7.Place the observer in the Arctic Circle and run the simulation. Explain what occurs for the observer over the year. 8.Place the observer close to your present latitude and run the simulation. Explain what the observer experiences over a year.
Mean Solar Days Mean Solar Day: The average value of the solar day (24 hours) , which changes slightly in length during the year, and month as the earth’s speed varies in its orbit because of the gravitational pull of the moon, and of the sun and surrounding planets. Solar day is longer as the earth is moving farther away from the sun.
Precession • Axial Precessionis a change in the orientation of the rotational axis of a rotating body. On earth it is gradual due to the gravitational pull of the moon and surrounding planet. The gradual change occurs every 26,000 years (or the soltice and equinox is slower 20min a year) • http://en.wikipedia.org/wiki/File:Gyroscope_precession.gif
Topography • Latitude: The angular distance north and south of the equator by increment of 15 degree. The North pole is 90 degree north of the equator, and the south pole is 90 degree south of the equator. Latitude lines are moving east and west on the sphere. Northern sphere, the latitude can be measured by finding the altitude of the Polaris Star, and in Southern sphere with the Southern Cross.
Topography (cont.2) • Longitude: Meridian lines that runs north to south of the earth sphere. Each line is 15 degrees moving east or west in relationship to the primary meridian line. The primary Meridian line is in Greenwich, England is at 0 degree and the International Date line is 180 degree longitude in semicircle. One could calculate one’s longitude by equation: • [Greenwich time - Your time] 15= longitude
Topography (cont.3) • Topographic Map: a detailed map of the landscape that shows a wide range of features from elevation to temperatures, etc. • Isoline: A line on a map or chart along which there is a same value for variables such as temperature or rainfall. Isoline show s field condition on a two-dimensional surface. • Contour Line: Line on a map or chart that indicate an area of interest. It is an isolinefor an elevation field. The contour interval is the distance between two contour lines
InterActive #4 MAP and LoCATION http://www.ck12.org/flx/render/embeddedobject/1643 • 1.What are lines of latitude? • 2.How far apart are the lines of latitude ,in degrees, in miles? • 3.What are the latitudes of the Equator ,the Tropic of Cancer ,and the Tropic of Capricorn? Characteristics of the regions found between the Tropic of Cancer and Tropic of Capricorn? • 4.Where are the Arctic and Antarctic circle? What are the characteristics of the regions that are found pole ward of these circles? • 5.What are lines of longitude? • 6.Where do the meridians meet? • 7.What is the Prime Meridian? Where is it located? • 8.How are longitude and latitude measured? • http://www.kidsgeo.com/geography-games/latitude-longitude-map-game.php
Azimuth: An angular measurements used to locate an object, star, etc. In a compass, it is measured around the horizon from the true north 0 degree to the south pole at 180 degree, with a 360 degree on the horizontal position. • Gradient: A measure of change in a physical quantity such as temperature or pressure over a specified distance. It is the slope. The steeper the slope the greater the change. • Gradient = amount of change in quantity • Distance in which change occurs. • Altitude: The angle in degree of an object above the horizon. This is the vertical angle
CalCulation • Calculation: <angle in degree = distance between two locations • 360 degree x • . • percent error.= ( actual distance- calculated distance) x 100 • actual distance • If Earth’s accepted circumference is 40,008 km and your calculated distance is 35,000km then percent error is ( 40,008-35,000/40008) x100= 12.5% error