EARTH-SUN RELATIONSHIPS

UNIT OBJECTIVES

•

EXPLAIN THE EFFECTS OF THE EARTH-SUN RELATIONSHIP ON LIFE ON EARTH.

•

IDENTIFY THE FACTORS THAT CONTRIBUTE

TO EARTH’S CLIMATES.

•

DESCRIBE THE MAJOR CLIMATE PATTERNS FOUND ON EARTH.

EARTH-SUN RELATIONSHIPS

OBJECTIVES

• DESCRIBE HOW EARTH’S POSITION IN RELATION TO THE SUN AFFECTS TEMPERATURES ON

EARTH.

• EXPLAIN HOW EARTH’S ROTATION CAUSES DAY AND NIGHT.

• DISCUSS THE RELATIONSHIP OF THE EARTH TO THE SUN DURING EACH SEASON.

• IDENTIFY HOW GLOBAL WARMING MIGHT AFFECT EARTH’S AIR, LAND, AND WATER.

EARTH-SUN RELATIONSHIPSTERMS TO KNOW PLACES TO LOCATE

CLIMATE SEASONS TROPIC OF CANCER

AXIS ECLIPTIC TROPIC OF CAPRICORN

TEMPERATURE ENERGY EQUATOR

REVOLUTION ROTATION POLES

EQUINOX CONDUCTOR

SOLSTICE CONVECTION

GREENHOUSE EFFECT ADVECTION

GLOBAL WARMING RADIATION

WEATHER PERIHELION

APHELION

EARTH-SUN RELATIONSHIPS

THE SUN, THE BRIGHTEST STAR IN OUR SKY, IS A MAJOR FACTOR IN CREATING EARTH’S

CLIMATES. THE SUN, COMPOSED OF HYDROGEN, HELIUM, AND OTHER GASES, ROTATES ON

AN AXIS AT ABOUT THE SAME ANGLE AS THE EARTH’S AXIS. ONLY A TINY FRACTION OF THE

POWER GENERATED BY THE SUN REACHES THE EARTH.

OUR SOLAR SYSTEM

DIMENSIONS AND DISTANCES

• EARTH’S ORBIT

• AVERAGE DISTANCE FROM EARTH TO THE SUN IS 150,000,000 KM (93,000,000 MI).

• PERIHELION

• CLOSEST AT JANUARY 3.

• 147,255,000 KM (91,500,000 MI).

• APHELION

• FARTHEST AT JULY 4.

• 152,083,000 KM (94,500,000 MI).

• EARTH IS 8 MINUTES 20 SECONDS FROM THE SUN.

• PLANE OF EARTH’S ORBIT IS THE PLANE OF THE ECLIPTIC.

EARTH’S TILT AND ROTATION

• EARTH IS CURRENTLY TILTED AT AN ANGLE OF ABOUT 23½°. BECAUSE OF THE TILT OF THIS

AXIS, NOT ALL PLACES ON EARTH RECEIVE THE SAME AMOUNT OF DIRECT SUNLIGHT AT

THE SAME TIME.

AXIAL TILT AND PARALLELISM

EARTH’S REVOLUTION

• EARTH TRAVELS IN AN ORBIT AROUND THE SUN, COMPLETING ONE TRIP ABOUT EVERY365

DAYS.

• THE SEASONS ARE CAUSED BY THE EARTH’S REVOLUTION AROUND THE SUN AND THE

EARTH’S TILT.

• THE EQUATOR DIVIDES EARTH INTO THE NORTHERN AND SOUTHERN HEMISPHERES. WHEN

ONE HEMISPHERE EXPERIENCES WINTER, THE OTHER EXPERIENCES SUMMER.

REVOLUTION AND ROTATION

THE POLES

• THE NORTH POLE AND THE SOUTH POLE ARE LOCATED AT EITHER END OF THE EARTH’S

AXIS.

• EACH POLE RECEIVES CONTINUOUS INDIRECT SUNLIGHT SIX MONTHS EACH YEAR.

• WHILE ONE RECEIVES CONTINUOUS SUNLIGHT, THE OTHER RECEIVES LITTLE TO NO

SUNLIGHT.

- UNEVEN DISTRIBUTION OF INSULATION.- INTENSITY IS SEASONAL & LATITUDINAL.- MOST INTENSE AT THE SUB-SOLAR POINT

THE TROPICS OF CANCER AND CAPRICORN

• THE LINE OF LATITUDE AT 23½°N IS CALLED THE TROPIC OF CANCER

– THE NORTHERN MOST LATITUDE ON THE EARTH TO RECEIVE THE SUN’S DIRECT RAYS.

• THE LINE OF LATITUDE AT 23½°S IS CALLED THE TROPIC OF CAPRICORN

– THE SOUTHERN MOST LATITUDE TO RECEIVE THE SUN’S DIRECT RAYS.

SEASONALITY

• SEASONAL CHANGES.

– SUN’S ALTITUDE

– ANGLE ABOVE HORIZON.

– DECLINATION

– LOCATION OF THE SUB-SOLAR POINT.

– LENGTH OF DAYLIGHT.

REASONS FOR SEASONS

• REVOLUTION.

• ROTATION.

• TILT OF EARTH’S AXIS.

• AXIAL PARALLELISM.

• SPHERICITY.

REASONS FOR SEASONS• REVOLUTION

– EARTH REVOLVES AROUND THE SUN.

– VOYAGE TAKES ONE YEAR.

– EARTH’S SPEED IS 107,280 KMPH (66,660 MPH)

• ROTATION

– EARTH ROTATES ON ITS AXIS ONCE EVERY 24 HOURS.

– ROTATIONAL VELOCITY AT EQUATOR IS 1,674 KMPH (1,041 MPH)

• TILT OF EARTH’S AXIS

– AXIS IS TILTED 23.5° FROM PLANE OF ECLIPTIC.

• AXIAL PARALLELISM

– AXIS MAINTAINS ALIGNMENT DURING ORBIT AROUND THE SUN.

– NORTH POLE POINTS TOWARD THE NORTH STAR(POLARIS)

• SPHERICITY

ANNUAL MARCH OF THE SEASONS• WINTER SOLSTICE

– DECEMBER 21 OR 22.

– SUBSOLAR POINT, TROPIC OF CAPRICORN.

• SPRING EQUINOX

– MARCH 20 OR 21.

– SUBSOLAR POINT, EQUATOR.

• SUMMER SOLSTICE

– JUNE 20 OR 21.

– SUBSOLAR POINT, TROPIC OF CANCER.

• FALL EQUINOX

– SEPTEMBER 22 OR 23.

– SUBSOLAR POINT, EQUATOR

ANNUAL MARCH OF THE SEASONS

EARTH-SUN RELATIONSHIPS

• KEY POINTS

• THE EARTH’S POSITION IN RELATION TO THE SUN AFFECTS TEMPERATURES ON

EARTH.

• THE ROTATION OF THE EARTH CAUSES DAY AND NIGHT.

• THE EARTH’S REVOLUTION AND ITS TILT IN RELATION TO THE SUN PRODUCE

THE SEASONS.

• GLOBAL TEMPERATURES MAY BE INCREASING AS A RESULT OF HUMAN

ACTIVITY

EARTH’S REVOLUTION

• DISCUSSION QUESTION

• HOW DOES THE REVERSAL OF SEASONS IN THE NORTHERN AND SOUTHERN HEMISPHERES

AFFECT THE LIVES OF PEOPLE ON EARTH?

• POSSIBLE ANSWER: FOOD CROPS CAN BE PRODUCED YEAR-ROUND BECAUSE OF THE

REVERSAL OF SEASONS, SO FRESH FRUITS AND VEGETABLES GENERALLY ARE AVAILABLE

ALL YEAR LONG

CRITICAL THINKING

Q: DRAWING CONCLUSIONS WHAT EFFECTS DOES THE EARTH’S TILT ON ITS AXIS

HAVE ON YOUR DAILY LIFE?

A: THE TILT CAUSES TEMPERATURE VARIATIONS AND AFFECTS ANY DAILY ACTIVITIES

THAT ARE DEPENDENT ON WEATHER OR TEMPERATURE(CHOICE OF CLOTHING,

OUTDOOR ACTIVITIES, INDOOR HEATING OR COOLING, AND SO ON).

CRITICAL THINKING

Q: ANALYZING INFORMATION WHAT WOULD YOU PACK IF YOU WERE VISITING

ARGENTINA IN DECEMBER?

A: YOU WOULD PACK CLOTHING FOR WARM WEATHER (IN LOW ELEVATIONS) AND

WARM CLOTHING FOR MOUNTAINS OR EXTREME SOUTHERN LATITUDES IF YOU

WERE VISITING ARGENTINA IN DECEMBER.

ANALYZING DIAGRAMS

Location Study the diagram of the seasons below. In what months do

the sun’s rays strike the Equator directly? The Tropics of Cancer and Capricorn?

ANALYZING DIAGRAMS

The sun’s rays strike the Equator directly in March and September. They strike

the Tropics of Cancer and Capricorn in December or June.

EARTH’S TILT AND ROTATION

DISCUSSION QUESTION

Q: WHICH PLACES ON EARTH RECEIVE THE MOST DIRECT SUNLIGHT? HOW DOES THIS

PHENOMENON AFFECT THEIR CLIMATES?

A: REGIONS IN THE TROPICS RECEIVE THE MOST DIRECT SUNLIGHT. THESE REGIONS ARE

GENERALLY WARM OR HOT YEAR-ROUND, DEPENDING ON THEIR ELEVATION.

CLIMATE AND WEATHER

DISCUSSION QUESTION

Q: THINK ABOUT YOUR LOCATION AND THE EARTH’S RELATIONSHIP TO THE SUN. HOW

DOES THE EARTH-SUN RELATIONSHIP AFFECT YOUR LIFE?

ASSIGNMENT: EARTH/SUN RELATIONSHIPS (TEAM PROJECT)

• SEASONAL WEATHER AND CLIMATE ARE RELATED TO EARTH/SUN RELATIONSHIPS. FOCUS

YOUR EFFORTS ON THE OKLAHOMA CITY METROPOLITAN REGION, AND GATHER CLIMATE

STATISTICS AND SEASONAL EARTH/SUN RELATIONSHIPS. ESTABLISH THE

LATITUDE/LONGITUDE FOR WILL ROGERS INTERNATIONAL AIRPORT. COLLECT CLIMATE

STATISTICS (DAILY HIGH AND LOW TEMPERATURES AND MONTHLY MEAN HIGH AND MEAN

LOW TEMPERATURES) FOR THIS STATION FOR ONE YEAR. ALSO COLLECT SEASONAL DATA

SUCH AS THE DAILY CHANGES IN THE LENGTH OF DAYLIGHT HOURS, THE DAILY LENGTH

OF DARKNESS HOURS, AND MAXIMUM AND MINIMUM DAILY SUN ANGLES (HEIGHT AT

SOLAR NOON) AND COMPASS AZIMUTHS (POSITIONS OF THE SUN). DETERMINE THE

RANGE OF THESE VALUES FOR EACH OF THE THREE SEASONS. CREATE A TABLE FOR ALL

VARIABLES YOU HAVE COLLECTED.