Insolation Incoming Solar Radiation Energy in Energy out

Insolation = Incoming Solar Radiation Energy in = Energy out or, Insolation In = Heat Out (Earth only emits heat)

Factors 1. Angle of insolation - direct or indirect 2. Length of Day - how much sunshine is available. 3. Type of Surface: -- light or dark -- rough or smooth

Angle of Insolation

Angle of Insolation

Axis Tilted Earth’s axis tilts 23. 50 Always tilts the same way = parallelism Seasons result.

Parallelism

Seasons

Equinox = when the sun is directly over the equator. Day and night are equal = 12 hours long Sun rises due East, sets due West Vernal (spring) Equinox = March 20 Autumnal (fall) Equinox = Sept. 22

Solstice = sun stop Summer Solstice ( 6/21) = Sun is directly over 23. 50 N (Tropic of Cancer) = most daylight Winter Solstice (12/21) = Sun is directly over 23. 50 S (Tropic of Capricorn) = least daylight

Rotation Daily Motion = stars and planets rise in the East and set in the West. Why? Earth rotates counterclockwise at 15 o / hr. Evidence: - Foucault’s Pendulum - Coriolis Effect – all winds move rightward in the northern hemisphere

Length of Day How long is a day? Is it 24 hours or 23 hrs. 56 minutes? Sidereal Day = actual time it takes to rotate 3600 (23 h 56 m). But, earth revolves around sun 10 in a day. So, it takes an additional 4 minutes to complete turn. Solar Day = Noon to Noon = Time it takes to rotate 3610 (24 h).

Revolution Earth revolves around Sun 1 o / day. Also counterclockwise. Evidence: Seasons. Constellations change during year.