150 likes | 356 Views
Seasons. Seasons cont. Temperate: lies between tropics Polar: polar circles In temperate and polar regions generally four seasons are recognized: spring, summer, autumn (Fall), winter. Zones Highlighted. Why?.
E N D
Seasons cont. • Temperate: lies between tropics • Polar: polar circles • In temperate and polar regions generally four seasons are recognized: spring, summer, autumn (Fall), winter.
Why? • During June, July, and August; the northern hemisphere is exposed to more direct sunlight because the northern hemisphere faces the sun. • The same is true of the southern hemisphere in December, January, and February.
Explaination • The tilt of the Earth causes the Sun to be higher in the sky during the summer months, causing a longer day.
The Tilt • We are tilted 23.5 degrees • This exposure alternates as the Earth revolves in its orbit. Therefore, at any given time, regardless of season, the northern and southern hemispheres experience opposite seasons.
Seasons cont. • Seasonal weather differences between hemispheres are further caused by the elliptical orbit of Earth. Earth reaches perihelion (the point in its orbit closest to the Sun) in January, and it reaches aphelion (farthest point from the Sun) in July.
Daylight hours • Any point north of the Arctic Circle or south of the Antarctic Circle will have one period in the summer when the sun does not set, and one period in the winter when the sun does not rise. • Other regions change by only a few hours each season
Seasons cont. • In the conventional United States calendar: Winter (89 days) begins on 21 December, the winter solstice; spring (92 days) on 20 March, the vernal equinox; summer (93 days) on 21 June, the summer solstice; and autumn (90 days) on 22 September, the autumnal equinox
Moon and the Seasons • The moon stables the axis, which keeps the seasons happening, and to keep the poles from tilting over so far that the sun can do major damage to the ice caps. • Without a moon, the axis would become unstable, and the seasons and the stability of the ice caps would go haywire. Had earth not paired up with her satelite, it is quite possible that she would never have been able to sustain life as we know it.
Do other planets have seasons? • (Do not write) So when our North Pole is tilted toward the sun, we get summer in the Northern Hemisphere (winter in the south). When the South Pole is tilted toward the sun, we get winter. • All these planets have tilts Venus — 23 degrees tilt, Earth — 23.5, Mars — 24, Jupiter — 3, Saturn — 27
Seasons cont. • http://www.teachersdomain.org/resource/ess05.sci.ess.eiu.seasonsgame/