Earths Motions

Earths MotionsRotation Revolution - Precession

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At all times, half of Earth is illuminated by the sun and half is in the dark.

Daytime and nighttime are the result of Earths rotation on its axis.

Earths axis tilts at an angle of 23.5 and points toward the North Star.2Learning Targets

Earths RotationThe spinning of Earth on its axis is called rotation.The AXIS is an imaginary line passing through Earths center through the N. and S. Poles.The Sun will illuminate only half the Earth at a time.

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Obliquity Flash

Earths RotationRotates Eastward (From West East)Counter-clockwise in Northern Hemisphere.Clockwise in Southern HemisphereSun appears to rise in the East and set in the West.

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Sun in Sky Flash

Earths Rotation CausesEarth to stay upright in orbit.Bulge at the equator oblate spheroid shapeDay and Night

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Earths Rotation Causes Earth to stay upright in orbit.

The Earth is tilted 23.5The N. Pole points toward the star Polaris

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Spinning Earth Click HereNon Spinning Earth Click Here

Earths Rotation Causes Earth to bulge at the equator

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Poles rotation is almost 0 mphUS-Latitudes rotation is between 700 900 mph Equator rotation is 1000 mph

Earths Rotation Causes Day and Night

8DAYTIME: When we are on the side of Earth facing the sun.NIGHTTIME: When we are on the side of Earth opposite the sun.

1 rotation = 24 hours (1 day)

Earths Rotation Causes Day and Night

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It is Earth that is moving (rotating).The Sun is stationary (almost) The Sun just appears to move.

Earths RotationCheck your understanding

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DAY NIGHT THINK QUESTIONS

Earths Rotation CausesEarth to stay upright in orbit.Bulge at the equator oblate spheroid shapeDay and Night

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Pendulum at the Franklin Institute

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DRAW A DIAGRAM OF WHAT YOU SEEHow does the pendulum support the idea that Earth rotates Provide evidence to support your claim.DRAW A DIAGRAM OF WHAT YOU SEEDescribe what you seeDescribe what you see

Evidence of RotationFoucault PendulumA pendulum is suspended above Earths surface.Once a pendulum is set in motion it will continue to move in the same direction.The Earth spins underneath the pendulum.The Pendulum seems to change directions because Earths rotation.

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Earths Precession18A slow movement/changing of direction around a point or axis of a spinning body.The top does not fall over as long as it stays spinning.

Earths Precession19The Earth wobbles on its axis once every 26,000 years.Earths precession moves opposite to its rotation.Earths axis will not straighten due to this constant rotation.

Spinning Earth Click HereNon Spinning Earth Click Here

Moving toward Vega20

The movement of one object around another object is called revolution.While Earth spins, it also moves around the sun.Earth revolves counterclockwise (N. Pole) around the sun at 66,000mph .1 Revolution takes 365.25 rotations (days).A day is added to the calendar every 4 years in February to account for the extra 0.25 day rotation.21Earths Revolution

01_earthsun_Flash

The movement of one object around another object is called revolution.While Earth spins, it also moves around the sun.Earth revolves counterclockwise (N. Pole) around the sun at 66mph .1 Revolution takes 365.25 rotations (days).A day is added to the calendar every 4 years in February to account for the extra 0.25 day rotation.22Earths Revolution

01_earthsun_Flash

The path Earth takes around the sun is called an orbit.Earths orbit is in the shape of an ellipse (flat oval)23Earths Revolution

The path Earth takes around the sun is called an orbit.Earths orbit is in the shape of an ellipse (flat oval)24Earths Revolution

0408_rotatingearth_Flash

The sun is closer to one side of the ellipse than the other.Perihelion point along Earths orbit when Earth is closest to the sun. (JANUARY)Aphelion Point along Earths orbit when Earth is farthest from the sun (July)25Earths Revolution

Drawing of Earth in its Orbit

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Ships sailing over the horizon will appear to sink as they sail from port, as they sail over the horizon they follow the curvature of Earth and move below the horizon.Photographs and models taken from space show a round Earth.A lunar eclipse casts Earths shadow on the moon and the curvature of Earth can be seen.The changing positions of the certain stars such as Polaris can be viewed at different angles from different latitudes. Shadows at local noon at different latitudes will have different lengths at different latitudes. The closer to the equator the more direct the light and the shorter the shadow.28Describe 2 pieces of Evidence that support Earths shape.

Earth stays upright at 23.5 degrees and will not topple over in its orbit because of Earths rotation.Earth takes on an oblate spheroid shape and gets wider at the equator and flatter at the poles as a result its fast rotation.The Earth will rotate in and out of the sunlight causing an observer on Earth to experience a certain amount of daylight and darkness.

29Describe two factors that result from Earths rotation.

Once a pendulum is set in motion it will continue to move in the same direction. The Earth rotates underneath the pendulum. The Pendulum seems to change directions because Earth is rotating underneath. From the perspective of an observer on Earth it appears that the pendulum changes direction, but when seen from above Earth (space), the pendulum stays swinging in the same direction and the Earth rotates under giving the appearance that it changed direction.30How does a pendulum provide evidence of Earths rotation?

1 day is 1 complete rotation in and out of the suns light. 1 year is 1 complete revolution around the sun.31How is the length of day and year related to Earths movement through space?

Gyroscope LabEarths MotionsROTATIONREVOLUTIONPRECESSIONThe spinning motion of a planet on its axis.The movement of an object around another object.The movement of the rotational axis (wobbling) of an object.

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You must Have at least 3 different procedures.Write out the steps that your group will follow in detail here.Diagrams of gyroscope Labels on DiagramArrows representing directionStatements describing the motion observedInferencesIdentify how the gyroscope resembles the rotation, revolution, and precession of Earth

35Rotation vs. Revolution ReviewThe spinning motion of a planet on its axis.The movement of 1 object around another object.Counter Clockwise North HemisphereCounter ClockwiseNight and DayYear1 Rotation = 24 Hours1 Revolution = 1 Year = 365.25 DaysPoles 0 mphEquator 1000 mph66,000 mphEarth to stay at 23.5 tiltOblate SpheroidSeasons are caused by Earths tilt and Revolution around the sun.

36EARTHAxisOrbit24 hours1 Year or 365.25 rotationsNight and DayYearrotates on itscompleting 1 trip in causescompleting 1 trip in causesrevolves on its

What is Earths Shape?Oblate Spheroid

What is the axis?Imaginary line that runs through geographic N. and S. poles at 23.5 degrees.

What causes night and day?Day and night is caused by Earths rotation in and out of the suns light.

37Review Questions

If seen from the North Pole perspective, which direction does Earth rotate?Earth rotates counter clockwise

What does the sun appear to do during a typical day?The sun appears to move across the sky from east to west

What shape is the Earths orbit for revolution around the sun?Earths orbit is in the shape of an ellipse.38Review Questions

When is the Earth closest to the sun? January

What is this point called?Perihelion

When is the Earth farthest from the sun?July

What is this point called?Aphelion

Whats wrong with this sentence: Earth revolves on its axis.Earth rotates on its axisEarth revolves on its orbit39Review Questions

What would you tell someone if, when asked why it is warmer in the summer and colder in the winter, they said that it is because we are closer to the sun in the summer and farther away in the winter?When the Earth is closest to the sun the time of year is January, when the Earth is farthest from the sun the time of year is July.In January, the Northern hemisphere is experiencing WinterIn July, the Northern hemisphere is experiencing Summer. Therefore how close or far the Earth is from the sun does not determine whether it is summer or winter.40Review Questions

Draw a diagram, clearly (with detail), showing the Earth in its motion around the sun. Label when it is closest and farthest away from the sun. Use appropriate terms and dates. 41Review Questions

In the space below, draw and explain how and why you think we have seasons. Show the position of Earth with respect to the sun at each season. Offer an explanation for why that season is occurring where you have it drawn it. 42Review Questions

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