Kepler’s Laws
Kepler’s LawsJohannes Kepler
Mars’ orbit is not a perfect circle, it is elliptical
The speed of Mars’ orbit changes
Closer to sun = faster
Farther away from sun = slower
Lead to Kepler’s 3 Laws
Kepler’s 1st LawThe path of each planet around the sun is an ellipse with the sun at one focus
Kepler’s 2nd LawEach planet revolves so that the “imaginary line” that connects it to the sun sweeps equal amount of area in equal time intervals
Closer to sun = faster
Farther away = slower
Kepler’s 3rd LawThe square of a planet’s orbital period is proportional to the cube of its distance from the sun
Orbital period - how long it takes to orbit the sun
Astronomical Unit (AU) – average distance between Earth and sun – 150 million km
T2 = d3 ; T = orbital period, d=distance from sun in AUs
Kepler’s 3rd LawT2 = d3
Mars has period (T) of 1.88 years (T = 1.88)
(1.88)2 = 3.54
d3 = 3.54
d = 1.52 AU
Kepler’s Laws Tri-fold
Use a tri-fold/brochure to explain Kepler’s 3 Laws. There should be no words other than labeling each 3rd as to which law you are demonstrating. You may also use the formula for Kepler’s 3rd law.
OrbitsBarycenter – point between two objects where they balance each other
When a moon orbits planet, or planet orbits a star, both bodies are orbiting around a point that lies outside of the larger body (star/planet)
http://en.wikipedia.org/wiki/Barycentric_coordinates_(astronomy)
http://www.youtube.com/watch?v=KnHUAc20WEU
http://www.youtube.com/watch?v=rKo6tfFtZg8(2:59)
OrbitsThe Sun is NOT a stationary object.
Sun moves as the planets tug on it
Sun orbits the solar system’s barycenter
Moon and Earth Relationship
Earth pulls on the moon, and moon pulls on Earth
This “tugging” from the moon can cause the Earth to bulge
Moon and Earth Relationship
Earth’s solids cannot give, however water does, causing our tides
Two high tides and two low tides a day
12hrs and 25 min between two high tides
Moon and Earth Relationship
Rise and fall daily due to Earth, Sun, and Moon interactions
Since earth is rotating, we experience two tides each day
Moon and Earth Relationship
Spring Tides – when moon and sun interact together and form extreme tides.
Occurs during full and new moons
Moon and Earth Relationship
Neap Tides – moon and sun pull at right angles and cancel each other out...very weak tides
http://www.youtube.com/watch?v=l37ofe9haMU
http://www.youtube.com/watch?v=rRPtNAA-9UE
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