4.2 E ARTH ’ S R OTATION DAHS Mr. Sweet 1 O BJECTIVES Give evidence of Earth’s rotation. Relate...
-
Upload
alvin-mclaughlin -
Category
Documents
-
view
216 -
download
0
Transcript of 4.2 E ARTH ’ S R OTATION DAHS Mr. Sweet 1 O BJECTIVES Give evidence of Earth’s rotation. Relate...
4.2 EARTH’S ROTATIONDAHS
Mr. Sweet
1
OBJECTIVES
Give evidence of Earth’s rotation. Relate Earth’s rotation to the day-night cycle
and the time zones.
2
Evidence for Rotation
Jean Foucault in 1851 Pendulum Direction of swing
does not change Shifts 11o per hour in
clockwise motion Earth is turning
beneath the pendulum
3
EVIDENCE FOR ROTATION
Coriolis Effect Wind and water is
deflected due to spin of earth
Right in North and Left in South
4
EVIDENCE FOR ROTATION
Change from day to night.
5
Axis
Imaginary line from pole to pole
Orbital Plane Earth’s path around
the sun Axis tilted to 23.5o
Pointed at Polaris Star Called Parallelism
6
Rate of Rotation
360o every 23 hours, 56 minutes, 4.1 seconds
15o every hour Distance traveled at
Equator is 40,074 km 1690 km per hour
Poles is 0 km
7
Measuring Time
Earth rotates clockwise
Half of earth is light and half dark
24 hour day Solar noon is when
sun is directly overhead Moves westward 15o
every day or 1o every 4 minutes
8
STANDARD TIME ZONES
24 time zones Each 15o of longitude wide Each time zone centered on a line of
longitude called a time meridian All area in the time zone keep the same time Clock time is the average solar time at the
zone’s time meridian Rarely a straight line on land
9
U.S. TIME ZONES
10
WORLD TIME ZONES
11
PRIME MERIDIAN
Arbitrary line in Greenwich, England
East of the PM clocks are set earlier
West of the PM clocks are set later
12
INTERNATIONAL DATE LINE
The longitude at which the date changes
Moving west the date is one day later
Moving east the date is one earlier
Western half is one day ahead of the eastern half USA is one day
behind Eastern Asia 13
SECTION REVIEW 4.2
Page 78 Complete questions 1, 2, 3, 4, 5
14