BELLRINGER Vocabulary : Section 2 Solar system Orbit Atmosphere Axis Revolution Summer solstice Winter solstice equiniox

Geography – 7th Grade Chapter 1: Section 2

Chapter One: Looking at the Earth Section Two: The Earth in Space I. The Solar System A. The solar system is made up of the sun, Earth, eight other planets, and thousands of smaller bodies (moons, comets, and asteroids). The planets and smaller bodies revolve around the sun.

B. A planet follows an elliptical path around the sun. This is known as its orbit. C. There are two types of planets - those solid and small like Earth, and those that resemble balls of gas like Jupiter.

D. Earth is surrounded by a layer of air called the atmosphere. Nitrogen and oxygen make up about 99 percent of this layer. E. Earth makes two motions in space. It spins on an imaginary line (axis) that runs through the center of Earth between the North and South Poles. It takes 24 hours for Earth to complete one spin on this axis.

The other motion is its complete orbit around the sun, or revolution. This revolution takes 365 ¼ days, which accounts for our need for a leap year once every four years.

II. The Sun and the Seasons A.Earth is tilted 23 ½ degrees on its axis. Because of this, we have seasons as Earth rotates around the sun. B. The day in which the Northern Hemisphere receives the most amount of sunlight is the summer solstice. On this day, the sun is directly over the Tropic of Cancer.

C. The day in which the Northern Hemisphere receives the least amount of sunlight is the winter solstice. On this day, the sun is directly over the Tropic of Capricorn. D. The two days each year in which the sun is directly over the Equator are known as the equinoxes. Both hemispheres receive the same amount of sunlight on these days.