Standard and Essential Question S6E2c. Relate the tilt of the earth to the distribution of sunlight throughout the year and its effect on climate. How does the tilt of the earth affect the seasons and Earth’s climate?

The Seasons What is the difference between rotation and revolution ? What causes the earth’s seasons ? What is the position of earth during each season? How does Earth’s tilt cause temperature differences in the seasons ?

Rotation vs. Revolution The Earth ROTATES on its axis An axis is an imaginary line that goes through the center of the planet The earth is TILTED 23.5° from the vertical position of the axis The Earth REVOLVES around the sun This revolution takes approximately 365 days ( 1 year)

What causes the Earth’s Seasons ?

What causes the Earth’s Seasons ? The earth is divided by the equator into two halves called hemispheres ( North and South) The seasons are not the same on all parts of earth at the same time (winter in the Northern Hemisphere, summer in the Southern Hemisphere) http://www.fengshuiweb.co.uk/advice/hemisphere.htm

What causes the Earth’s Seasons ? Earth’s orbit + the way that the Earth tilts on its axis causes the seasons. The sun’s rays strike Earth unevenly- at different angles at different times of the year

What causes the Earth’s Seasons ? http://www.google.com/imgres?imgurl=http://www.learner.org/jnorth/images/imageshtml/earth-tilt.gif&imgrefurl=http://www.learner.org/jnorth/tm/ReasonsBack.html&h=397&w=500&sz=38&tbnid=zSrsnUpyQwApxM:&tbnh=90&tbnw=113&prev=/search%3Fq%3Dearth%2Btilt%26tbm%3Disch%26tbo%3Du&zoom=1&q=earth+tilt&usg=__Bq05HRctVKMbPsVAnB6PFBgQvnE=&docid=VA3okLH3f51z9M&hl=en&sa=X&ei=G9U5UYSqFYes8ATGhIHABg&sqi=2&ved=0CDsQ9QEwAQ&dur=7

Position of Earth The seasons are always opposite in Earth’s Northern and Southern Hemispheres.

Position of Earth The position where the Northern Hemisphere tilts towards the sun = summer. At the same time, its winter in the Southern Hemisphere WHY? The position where the Northern Hemisphere tilts away from the sun = winter. At the same time, its summer in the Southern Hemisphere

Position of Earth Two points where axis is not tilted away or toward the sun. These points mark the beginning of fall and spring Fall in Northern Hemisphere, Spring in Southern Hemisphere Spring in Northern Hemisphere, Fall in Southern Hemisphere

Position of Earth

Temperature and Daylight The sun’s rays deliver the most energy when Direct

Temperature and Daylight When its Winter in an area, the sunlight is Less direct, meaning the area receives less Energy from the sun When its Summer in an area, the sunlight is More direct, meaning the area receives more Energy from the sun

Temperature and Daylight The amount of daylight also changes with the seasons.

Temperature and Daylight The amount of daylight also changes with the seasons. Summer= more hours of daylight, so the sun heats Earth’s surface longer ( temperatures higher) Winter = less hours of daylight, so the sun heats Earth’s surface for a shorter amount of time ( temperatures lower) In the Northern Hemisphere, from Dec. 21st to June 21st the period of daylight gets longer, from June 21 to Dec. 21st, the period of daylight gets shorter

Temperature and Daylight Many parts of the earth do not have distinct seasons Places near the equator: receive direct sunlight all year long, so temperatures remain high The north and south poles: get less direct sunlight from farther poles, so even in summer, these places are still cold