APPARENT PATH OF THE SUN

How does the Sun’s path affect the amount of energy received on Earth?

HOMEWORK

• Textbook: read pages 257 – 260. • Do questions 17, 23-31.

SUN

• RISES IN THE EAST . . . SETS IN THE WEST

ANGLE OF INSOLATION

• Insolation: Incoming Solar Radiation is the sun's energy that enters the earth's atmosphere and surface.

• Angle of Insolation: the angle at which the sun’s rays strike the earth's surface.

• Intensity: a measure of the amount of radiation that strikes a unit area of the earth's surface.

FACTORS THAT INFLUENCE THE AMOUNT OF ENERGY RECEIVED BY THE SUN

• Angle of Insolation – lower in the mornings and evenings– Higher in the afternoons

• Duration of Insolation– In NY, Sun is out for 15 hours in Summer– In winter, Sun is out only 9 hours

• Latitude of maximum insolation– North and South Poles are much colder than the

Equator.

FACTORS THAT INFLUENCE THE AMOUNT OF ENERGY RECEIVED BY THE SUN

• Intensity of Insolation – Higher the angle of insolation, the greater or

stronger the amount of energy– Lower the angle, the weaker the amount of

energy.

High Angle – Sun is directly overhead

High Angle – Sun is directly overhead with high intensity of energy - short shadows

LOW ANGLE – Sun is low in the sky –low intensity of energy

LOW ANGLE – Long shadows, lower intensity of Sun’s energy

IMPORTANT DATES

• JUNE 21: SUMMER SOLSTICE• DECEMBER 21: WINTER SOLSTICE• MARCH 21: VERNAL EQUINOX• SEPTEMBER 21: AUTUNM EQUINOX

IMPORTANT LATITUDES

• ZENITH – POINT DIRECTLY ABOVE• JUNE 21 – 23.5 NORTH (Tropic of Cancer)• DECEMBER 21 – 23.5 SOUTH (Tropic of Capricorn)• MARCH 21 & SEPTEMBER 21 - 0 (Equator)

SUN’S PATH

SUN’S PATH

SHADOWS

• In New York– Sun’s Path is always in the southern sky.

• Shadows are always opposite the Sun• Low Sun, Long shadows• High Sun, short shadows

SHADOWS

High Noon, December 11 at Reykjavik

High Sun, Short Shadows