6th Chp 2.1 Solar Energy

All life on Earth requires solar energy, or energy from the sun, to survive.

 –Amount of solar energy received changes constantly 

 –Earth’s rotation, revolution, tilt, and latitude all affect the amount of solar energy Earth receives.

Earth spins on its axis —an imaginary line that runs through the center of the planet around which it turns. 

It takes Earth 24 hours to make one rotation, or complete spin on its axis. 

As Earth spins, different parts of the planet face the sun, thus causing the changes from day to night.

Earth follows an orbit, or path, around the sun. 

It takes Earth 365¼ days to complete one revolution, or trip around the sun. 

Our calendar year is based on the time it takes Earth to complete its orbit.

At any give time of year, some places on Earth tilt toward the sun, and others tilt away. 

Places tilting toward the sun receive more solar energy and have warmer temperatures than those that tilt away.

 Latitude is the distance north or south of Earth’s equator. 

Low-latitude areas, those nearest the equator, receive direct rays from the sun all year. 

High-latitude areas, those farther from the equator, receive indirect rays from the sun and have colder temperatures.

Seasons are periods during the year that are known for a particular type of weather.

 –Many places experience four seasons: winter, spring, summer, and fall. 

 –In some parts of the world, seasons are based on the amount of rainfall

 •Earth tilts away from sun in winter and towards the sun in summer. 

 •Because of the Earth’s tilt, the Northern and Southern hemispheres experience opposite seasons.

•In spring, Earth begins to tilt toward sun, solar energy increases, temperatures rise, and days grow longer. 

 •In fall, the opposite occurs.

 •In the tropics, regions close to the equator,  seasons are marked by rainfall rather than temperature.

 •At certain times of year, winds bring either dry or moist air to the tropics, creating wet and dry seasons.