Earth-Sun Relationships Chapter 3 Section 1 Earth-Sun Relationships

Climate vs. Weather Climate is often confused with weather… Weather is the condition of the atmosphere in one place during a limited period of time Climate is the term for the weather patterns that an area typically experiences over a long period of time.

Climate vs. Weather con’t… Example of WEATHER : When you look out the window or watch the news to see if you need an umbrella today. Example of CLIMATE: People who live in Seattle frequently use umbrellas because of the rainy, wet climate.

Climate vs. Weather con’t… The climate & weather in a particular region is determined by many factors…the most important of which is the earth’s position in relation to the sun.

Earth’s Tilt & Rotation The Earth’s tilt is one reason for variations in sunlight. It is tilted at an angle, 23 ½ degrees, on an imaginary pole that runs from the North Pole to the South Pole.

Tilt & Rotation Con’t… Because of the tilt of this axis, not all places on the planet receive the same amount of direct sunlight at the same time. For this reason, the angle of tilt affects the TEMPERATURE…areas that receive a large amount of direct sunlight have warmer temps than places that receive little sunlight.

ROTATION The Earth rotates on it axis, making 1 complete rotation every 24 hours. It rotates from WEST to EAST. This is how we get day & night!

REVOLUTION While the planet is rotating on its axis, it is also REVOLVING around the sun. It takes about 365 days to complete one trip around the sun. The Earth revolves counterclockwise around the sun. “About” refers to leap year, Feb. 29th, every four years, as a result of 365 ¼ days.

Seasons The earth’s tilt & it’s revolution cause changes in the angle and amount of sunlight that reach different locations on the planet. This results in the seasons.

SEASONS Fall – September 22 Winter – December 22 Spring – March 21 Summer – June 21

SOLSTICE At 2 moments during the year the earth’s poles point toward or away from the sun more than at any other time. Definition: The time that the earth’s poles point at their greatest angle toward or away from the sun is called a solstice.

SOLSTICE con’t… Solstices occur around Dec. 21 & June 21. In the N. hemisphere, the day in Dec. on which the solstice occurs is the shortest day of the year and is the first day of winter. The day in June on which the solstice occurs is the longest day of the year and is the first day of summer.

EQUINOX Definition: An equinox, which means equal night in Latin, occurs twice a year when the earth’s poles are not pointed toward or away from the sun.

EQUINOX con’t Both hemispheres receive an equal amount of sunlight-exactly 12 hours. If you were to travel anywhere in the world during an equinox, daylight and darkness would last the same amount of time. Equinoxes occur around March 21 & Sept. 22 The March equinox signals the beginning of Spring & theSept. one signals the beginning of fall.

POLES The amount of sunlight at the Poles varies most dramatically as the earth’s revolution and tilt cause the changing seasons. For 6 months of the year, one Pole is tilted toward the sun and receives continuous sunlight, while the other Pole it tilted away from the sun and receives little to no sunlight.

POLES con’t… At the North pole, the sun never sets from about March 20-Sept. 23. It Is vice versa for the south pole. It switches 6 months later for each location!