Earth's Rotation & Revolution
1. Give evidence for Earth's rotation.
2. Relate Earth's rotation to the day-night cycle and the time zones.
3. Give evidence for Earth's revolution around the sun.
4. Describe Earth's path and rate of revolution.
5. Explain why the seasons occur.
rotation standard time zones time meridian prime meridian International Date Line revolution parallax summer solstice winter solstice vernal equinox autumnal equinox
Notes: (4-2& 4-3)
The success of every species on the planet lies in well they are suited (adapted) to their niche. Some species are nocturnal while others are diurnal and some species hibernate in the winter while others are active all year long. The development of of these niches are set up by the rotation and revolution of the Earth.
Although rotation and revolution continue throughout the day and year the axis of rotation and revolution are not on the same plane.
Rotation sets up our day and night cycles. The rotation was proved by the scientist Foucalt in 1851 when he noticed that his pendulum's sweep direction changed orientation at the rate of 11o per hour.
The revolution of the Earth on its axis is important in setting up the seasons. Evidence for this is in a phenomena called parallax where nearby stars appear to shift with regards to distant stars.
The direction of Earth's revolution is in the direction of its rotation. Because the path around the sun is not circular, we are closer to the sun at certain time of the year.
The tilt of the Earth with its elliptical orbit affect the period of day and night as well as the seasons. Here are some of the important dates to remember.
Vernal & Autumnal Equinox
(image: www.usd.edu/esci/figures/ 158280.JPG)
Last modified: February 03, 2003