1. Earth’s Motion

2. Do Now What is the shape of a planet’s orbit?
Describe how the planets of the solar system formed.
A galaxy is __________.
The modern heliocentric model states that the planets travel around the ____ in a _______ orbit.
Two types of evidence for the big bang theory include __________.

3. Lesson Essential Question
How does the Earth move?
(Rotation, Revolution, Precession, Nutation)

4. Notes on the Universe
The universe is made of galaxies which are made of many stars. Some stars have planetary systems similar to our solar system. Earth is a satellite planet of one particular star (our sun)

5. ROTATION Rotation – turning or spinning on it’s axis
Rotations CAUSE DAY and NIGHT
Earth rotates as it orbits AROUND the SUN
Spins Counterclockwise
one day to equal 24 hours

6. The Earth’s Axis The tilt of the axis is responsible for SEASONS
The axis moves counterclockwise
The Earth’s axis has a tilt of 23.5 degrees
When the axis is tilted TOWARDS the sun = WARM seasons in the NORTHERN HEMISPHERE and COOL seasons in the SOUTHERN HEMISPHERE

7. Revolution
Revolution – the motion of a body along a path around some point in space
Earth’s orbit is an elliptical
Earth orbits (revolves) the sun ONCE a year

8. Precession
The direction this axis of a planet is pointing in will change, but the tilt will not change.
This will change the stars near the pole but will not change the seasons (as long as the angle of the tilt, 23.5 in the case of Earth, stays the same)
The Earth’s axis points to two stars: Polaris and Vega

9. Nutation Nutation happens when the axis of a planet starts to wobble
The angle of the axis will change during nutation ½ degree one direction or the other
Nutation happens over the course of 18 years
Nutation is a direct result of the moon (or moons) of a planet

10. How it works…DRAW this diagram!

11. Let’s Take a Look
Rotation and Revolution

12. Barycenter
Barycenter – the point between 2 objects where they balance each other
The center of mass where 2 or more celestial bodies orbit each other.
KEY POINT – the Barycenter is CLOSER to the object that has the GREATER MASS.

14. The sun is NOT stationary in our solar system.
It moves as the planets tug on it causing it to orbit the solar systems’ barycenter.
The sun never strays too far from the solar system.

15. Exit Ticket
1. Identify the evidence that supports the Earth’s rotation. 2. What is the reason for Earth’s spheroidal shape (wider at the equator)? 3.

16. Summary of Rotation and Revolution

17. Rotation – Revolution Contrast & Comparison
Contrasts
Comparisons
Revolution vs. Rotation
Revolution= object moves around another object
Rotation = an object spin in one place
Orbit vs. Revolution
Orbit = path that object takes around another object
Revolution = object moves around another object
Revolution vs. Rotation
Both involve circular movement
Orbit vs. Revolution
The orbit is the path that an object takes while it is revolving another object

18. Rotation – Revolution Contrast & Comparison cont.
Contrasts
Comparisons
Rotation, vs. Rotation Axis vs. Equator
Rotation = spinning of an object
Rotation Axis = point on Earth where the spinning occurs
Equator = imaginary line that circles the middle of the Earth
Rotation, vs. Rotation Axis vs. Equator
The rotation of Earth occurs on the rotation axis
The equator is the midway point between the North and South Rotation axis

19. Rotation – Revolution Contrast & Comparison
Contrasts
Comparisons
Solstice vs. Equinox
Solstice = occurs when the Northern and Southern hemispheres have opposite weather (during summer and winter).
Equinoxes = occurs when the northern and southern hemispheres have equal weather (spring and fall)
Solstice vs. Equinox
Solstices and Equinoxes alternate seasons (spring equinoxes, summer solstice, fall equinoxes, winter solstice)

20. Seasons

21. December Solstice
The north end of Earth’s axis leans away from the sun = Winter Solstice
In the Northern Hemisphere = Winter
In the Southern Hemisphere = Summer
Temperatures are cooler in the Northern Hemisphere because solar radiation is more spread out and less concentrated during this time.

22. March Equinox
The number of daylight hours is 12 hour day and 12 hours night
In the Northern Hemisphere = Spring
In the Southern Hemisphere = Fall
The sunlight is distributed equally during this time

23. June Solstice
The north end of the Earth’s axis leans towards the sun = Summer Solstice
In the Northern Hemisphere = Summer
In the Southern Hemisphere = Winter
The temperatures is higher because the solar radiation is more concentrated during this time.

24. September Equinox
The number of daylight hours during the Fall is 12 hours of daylight and 12 hours of night
In the Northern Hemisphere = Fall
In the Southern Hemisphere = Spring
The sunlight is distributed equally

25. Eclipses

26. Eclipses
Eclipse – when an object passes between the observer and the object that emits light.
Two types – Solar (sun) and Lunar (moon)

27. Solar Lunar
The Moon blocks solar radiation from the Sun and solar radiation is blocked from reaching the Earth’s surface
During Solar Eclipse – the position of the Sun, Moon, and Earth are in a STRAIGHT LINE…in THAT order
The Earth blocks solar radiation from the Sun and solar radiation is blocked from reaching the Moon’s surface
During Lunar Eclipse – the position of the Sun, Earth, and Moon are in a STRAIGHT LINE…in THAT order

29. What are tides?
Tides are changes in the elevation of the oceans surface

30. Tides What causes tides? What is a spring tide? What is a neap tide?
Gravitational pull of the Sun and Moon
What is a spring tide?
When the high tide is higher than the normal tide because the Moon, Sun, and Earth are aligned in a straight line in the same direction.
What is a neap tide?
When the high tides are lower than normal tide because the Moon, Sun, and Earth are not aligned in a straight line in the same direction (right angle/perpendicular)

31. When do tides occur in relation to the moon?
Spring tides - occur during NEW and FULL moon because the GRAVITATIONAL forces are ADDED together.
Neap tides - occur during 1st and 3rd quarter moon because the GRAVITATION forces are OFFSET

32. What does it look like?

33. Tidal patterns

34. Tidal Pattern 1 Diurnal = Daily
One HIGH tide and One LOW tide each lunar day
Lunar day – tides occur 50 minutes later due to the rotation pattern of the Earth and the moon.

35. Tide Pattern 2
Semidiurnal – TWO high and TWO low tides. Each high and low tides are similar to each other
Occurs in the Atlantic Coast

36. Tidal Pattern 3 Mixed – TWO high tides and TWO low tides each day.
Each high and low tides are DIFFERENT from each other
Occurs on the West Coast