Earth’s Physical Geography

1. Earth’s Physical Geography Chapter 2, Section 1

2. Our Planet, the Earth • The Earth, sun, planets, and stars are all part of a galaxy, or family of stars. • What is the name of the galaxy we live in? • The sun is the center of our galaxy.

3. Days and Nights • Sun  93 million miles away; provides the Earth with light and heat • The Earth travels around the sun in an oval-shape path called an orbit • It takes one year (365 days) for the Earth to complete one revolution, a circular journey around the Earth

4. Days and Nights • Earth spins as it revolves around the sun on its axis, an imaginary line running through the Earth between the North and South poles • A complete turn takes 24 hours and is called a revolution • As Earth rotates… • It is daytime on the side facing the sun • It is night on the side away from the sun

6. Seasons • Earth’s axis is on an angle • At certain times of the year, days are long than nights • At other times, nights are longer than days • Earth’s orbit is at a tilt • The tilt causes a region to face toward the sun for more hours than it faces away from the sun • Days are longer • At other times, the region faces away from the sun for more hours than it faces toward the sun • Days are shorter

7. Seasons • Earth’s tilt and orbit cause changes in temperature during the seasons • The warmth you feel at any time of year depends on how directly the sunlight falls upon you

8. Latitudes • In some places on Earth, the sun is directly overhead at particular days during the year • On March 21 and September 23, the sun is directly above the Equator at 0 degrees latitude. • The days are almost exactly as long as the nights • Spring and fall equinoxes

9. Latitudes • Tropic of Cancer  23 ½ degrees North of the Equator • Sun shines directly above on June 21 or the 22nd • First day of summer (summer solstice) in the Northern hemisphere • Tropic of Capricorn  23 ½ degrees South of the Equator • Sun shines directly above on December 21 or 22nd • First day of winter (winter solstice) in the Northern hemisphere • When would summer solstice occur in the Southern hemisphere?

10. Latitudes • The area between the Tropic of Cancer and the Tropic of Capricorn is called the low latitudes, or the tropics. • Any location in the low latitudes receives direct sunlight at some time during the year. HOT!

11. Latitudes • Two other distinct regions  the Arctic Circle 66 ½ degrees north of the Equator and the Antarctic Circle 66 ½ degrees south of the Equator • The regions between these circles and the poles are high latitudes, or polar zones • Receive no direct sunlight… COLD!!

12. Latitudes • Middle latitudes, or the temperate zones, receive fairly direct sunlight at some times, and at others fairly indirect sunlight • Seasons occur here. • Each lasts about three months and has distinct patterns of daylight, temperature, and weather