1. EARTH'S MOTION

2. Rotation The spin of the Earth on its axis
(rate of 15 /hr)
Earth is tilted at an angle of 23.5 degrees from perpendicular
The Earth’s axis is always tilted in the same direction throughout its orbit (parallelism)

4. Evidence of Movement
Foucault Pendulum- Changes its direction of swing over time
Coriolis Effect- The deflection of air and water to the right in the northern hemisphere
Sorry, Bart Simpson was not right. Water DOES turn counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere, HOWEVER… in toilets, the direction is caused by the force of
the pump, not CORIOLIS!

7. Solar Time
The measurement of time based on the apparent movement of the sun through the sky
Solar Noon is the time of day when the sun is at its highest altitude above the horizon
Problem - solar noon does not occur at the same time for everyone (solar noon differs by approx. 1 minute for every 12 miles east/west of a specific location)

8. To make up for this “problem”, time zones were established (each 15 longitude wide – 1 hour of rotation)
Time zones begin at the Prime Meridian
Every 15 degrees EAST is +1 hour, every 15 degrees WEST is –1 hour
Clock time is the average solar time

10. Revolution
movement of the Earth around the sun in its elliptical orbit
One complete revolution is days (1 year)
In conjunction with AXIAL TILT, this causes a change in the seasons
no tilt of the axis = no seasonal changes
Evidence of movement: Change in visible constellations throughout the year

11. Solstices and Equinoxes
SOLSTICE - extremes from the sun
WINTER (perihelion) – 8 hours day/16 hr night
SUMMER (aphelion) – 16 hours day/8 hr night
EQUINOX – equal distances from the sun (equal days/nights)
Autumn (Vernal), Spring – 12 hours day/night

15. Nighttime on the Artic Circle during the Summer. The sun never sets
Nighttime on the Artic Circle during the Summer. The sun never sets! It’s always on the horizon.

19. Causes of Seasons Earth’s revolution Tilt of the Earth on its axis
Parallelism
More sunshine = more energy = warmer time of year
Less sunshine = less energy = cooler time of year