4.2Earth’s Rotation

• Rotation • Earth spinning on its axis

• Earth takes 24 hours or 1 day to make one complete rotation

• Rotation causes day and night

• Evidence of Earth’s rotation

• Foucault’s Pendulum– Pendulum swing

changed every hour, evidence that earth was turning under it

• Coriolis Effect– Winds are deflected

(turned) toward the west….due to Earth spinning or rotating toward the east

• Axis • Earth is tilted on its axis 23.5o

• Time • 24 hours in one day• 24 standard time zones

on Earth (15o of longitude each)

• Prime Meridian • Move westward – move clocks back to an earlier time

• Move eastward – change clocks to a later time

• International Date Line

• When travelers cross the International Date Line, they change their calendar by one day

• Move westward, go ahead a day