Physical Earth- Earth/Sun Relationships Mr. Bergum

Terms To Understand: Weather Tropic of Cancer Climate Tropic of Capricorn Axis Revolution Rotation Equinox Solstice

Questions to Answer: What are Equinoxes and Solstices? What is the difference between weather and climate? How does the tilt of the earth and its revolution affect temperature and seasons on earth?

I. The Difference Between Weather and Climate. A. The term weather means the condition of the atmosphere at a given time/place. B. Whereas climate indicates weather conditions in a geographic region over time. Both weather and climate are strongly influenced by solar energy in the form of heat and light.

II. The Earth and Direct Sunlight A. The earth sits on an axis or tilt in relation to our sun. B. The axis is tilted at 23.5° so different parts of the earth receive different amounts of solar energy. C. More at (low latitudes) tropics, very warm. D. Less at (high latitudes) polar regions, mostly cold.

II. The Earth and Direct Sunlight E. The earth moves in space in both a rotation, one complete spin on its axis and a revolution, one elliptical orbit around the sun. F. As the earth rotates and revolves the position of direct sunlight changes. G. This causes areas on earth to heat up and cool down at different rates.

II. The Earth and Direct Sunlight H. Certain lines on the earth show the position of the sun and direct sunlight and are called tropics. 1. The Tropic of Cancer is 23.5° N. of the equator. 2. The Tropic of Capricorn is 23.5° S. of the equator. I. A solstice occurs when the poles point at their greatest angle toward or away from the sun. 1. About June 21 summer solstice, Cancer has direct rays (Longest day). 2. About Dec 21 winter solstice, Capricorn has direct rays (Shortest day).

II. The Earth and Direct Sunlight J. An equinox occurs when direct sun rays are on the equator (“equal night”). 1. About March 21 is the spring equinox, Northern Hemisphere. 2. About September 21 is the fall equinox, Northern Hemisphere. (This is reversed in the Southern Hemisphere).