earth’s rotation chapter 4.2. objectives give evidence of earth’s rotation. give evidence of...
TRANSCRIPT
ObjectivesObjectives
Give evidence of Earth’s rotation.Give evidence of Earth’s rotation. Relate Earth’s rotation to the Relate Earth’s rotation to the
day-night cycle and the time day-night cycle and the time zones.zones.
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EVIDENCE FOR EVIDENCE FOR ROTATIONROTATION PENDULUM, 1851 PENDULUM, 1851
JEAN FOCAULT NO JEAN FOCAULT NO FORCE ON SWING, FORCE ON SWING,
NO NO DIRECTIONAL CHANGE = EARTH CHANGE = EARTH TURNING BENEATH TURNING BENEATH PENDULUMPENDULUM
CORIOLIS EFFECT – CORIOLIS EFFECT – WIND DIRECTIONAL WIND DIRECTIONAL CHANGECHANGE
EVIDENCE FOR EVIDENCE FOR ROTATIONROTATION
CORIOLIS EFFECT – CORIOLIS EFFECT – WIND DIRECTIONAL WIND DIRECTIONAL CHANGECHANGE
RIGHT IN THE RIGHT IN THE NORTHNORTH
AND LEFT IN SOUTHAND LEFT IN SOUTH
AXIS AND RATE OF AXIS AND RATE OF ROTATIONROTATION
ROTATION – COUNTERCLOCKWISE SPIN OF THE EARTH ABOUT IT’S AXIS.
TILTED 23.50 FROM PERPENDICULAR
1 ROTATION = 24 HR = 1 DAY
3600 / 24HR = 150 PER HOUR
10 / 4 MIN
RATE OF ROTATIONRATE OF ROTATION
LOCATION CIRCUMFERENCE ROTATIONAL RATE
POLES 0 MILES 0 MI/HR 420 NORTH 18,720 MI 780 MI/HR
EQUATOR 24,044 MI 1002
MI/HR
EFFECTS OF ROTATIONEFFECTS OF ROTATION
DAILY CHANGE DAILY CHANGE DAY TO NIGHTDAY TO NIGHT
SUN APPEARS TO SUN APPEARS TO RISE IN EAST RISE IN EAST AND SET IN AND SET IN WESTWEST
PENDULUM AND PENDULUM AND CORIOLISCORIOLIS
Day and Night VideoVideo
MEASURING TIMEMEASURING TIME
USED THE SUNUSED THE SUN RISE IN EAST SET IN WESTRISE IN EAST SET IN WEST EARTH ROTATES COUNTERCLOCKWISE WHEN EARTH ROTATES COUNTERCLOCKWISE WHEN
VIEWED FROM ABOVE NORTHPOLEVIEWED FROM ABOVE NORTHPOLE SUN MOVES IN AN ARC IN THE SKYSUN MOVES IN AN ARC IN THE SKY HIGHEST POINT IN ARC = SOLAR NOON = SUN HIGHEST POINT IN ARC = SOLAR NOON = SUN
DIRECTLY OVERHEAD TO AN OBSERVERDIRECTLY OVERHEAD TO AN OBSERVER– BECAUSE EARTH ROTATES, SOLAR NOON DOES BECAUSE EARTH ROTATES, SOLAR NOON DOES
NOT OCCUR AT THE SAME TIME DAILY NOT OCCUR AT THE SAME TIME DAILY – EX. PHILLY 75EX. PHILLY 7500 W AND DUBOIS 78 W AND DUBOIS 780 0 WW
STANDARD TIME STANDARD TIME ZONESZONES TIME MERIDIAN – EACH 150 FROM
THE PRIME MERIDIAN. CENTER LINE OF A TIME MERIDIAN 7 1/2O.
EACH TIME MERIDIAN (150) IS 1 HR DIFFERENCE IN TIME
EARTH ROTATES 3600 IN 24 HRS 3600/ 24 HOURS = 150 PER HOUR THEREFORE EACH TIME ZONE IS 150 OF LONGITUDE
iF THE TIME IN DUBOIS IS 1:00 PM, WHAT IS THE TIME IN:
LA, DETROIT AND DENVER?
US TIME ZONESUS TIME ZONES
EASTERN (75EASTERN (7500 W) W)
CENTRAL (90CENTRAL (9000 W) -1 W) -1
MOUNTAIN (105MOUNTAIN (10500 W) -2 W) -2
PACIFIC (120PACIFIC (12000 W) – 3 W) – 3
INTERNATIONAL DATELINE IDL – 1800 MERIDIAN
– OPPOSITE THE PRIME MERIDIAN WHEN TRAVELING:
– EAST ACROSS DATELINE – SUBTRACT A DAY
– WEST ACROSS DATELINE – ADD A DAY
only at midnight on the international dateline does earth have the same day!
How dateline works