Planet EarthPlanet Earth

Earth and the Sun’s EnergyEarth and the Sun’s Energy

Earth’s MovementEarth’s Movement

• Energy from the sun Energy from the sun helps crops grow, helps crops grow, provides light and provides light and warms the earth. The warms the earth. The Earth requires this solar Earth requires this solar energy to survive. The energy to survive. The amount any area amount any area receives at a given time receives at a given time is based on the is based on the revolution, rotation and revolution, rotation and tilt of the earth along tilt of the earth along with latitude and with latitude and changes all of the time.changes all of the time.

RotationRotation

• The Earth rotates on its The Earth rotates on its axis. You can imagine axis. You can imagine a rod placed through a rod placed through the Earth from pole to the Earth from pole to pole like an axle on a pole like an axle on a wheel and the Earth wheel and the Earth spinning round the spinning round the axle. One rotation is a axle. One rotation is a complete spin of the complete spin of the Earth. As the Earth Earth. As the Earth rotates, it seems as if rotates, it seems as if the Sun travels around the Sun travels around the Earth – however it the Earth – however it don’t!don’t!

Earth’s rotationEarth’s rotation

RotationRotation

• Earth’s rotation also Earth’s rotation also explains the change explains the change from night to day. from night to day. The half of the Earth The half of the Earth that is facing the Sun that is facing the Sun experiences daytime experiences daytime and the opposite and the opposite night. As a result, the night. As a result, the level of solar energy level of solar energy on Earth is constantly on Earth is constantly changing.changing.

RevolutionRevolution

• As the earth spins, it As the earth spins, it also travels in orbit also travels in orbit around the Sun. The around the Sun. The orbit is not perfect and orbit is not perfect and sometimes it is closer sometimes it is closer to the Sun and at times to the Sun and at times further away. It takes further away. It takes the Earth 365 ¼ Days the Earth 365 ¼ Days to complete one to complete one revolution around the revolution around the Sun. This is the basis Sun. This is the basis of our calendar – leap of our calendar – leap year and all.year and all.

RevolutionRevolution

TiltTilt

• The earth is tilted at 23 The earth is tilted at 23 1/3 degrees from the 1/3 degrees from the vertical. This means vertical. This means that any one time, a that any one time, a given spot on the Earth given spot on the Earth is tilted away from the is tilted away from the Sun and others towards Sun and others towards it. Those tilting towards it. Those tilting towards the Sun receive more the Sun receive more energy and are warmer energy and are warmer and those tilting away and those tilting away the opposite.the opposite.

LatitudeLatitude

• The distance north or The distance north or south of the equator also south of the equator also affects the amount of affects the amount of solar energy a location solar energy a location receives. Those closer receives. Those closer to the equator receive to the equator receive direct rays from the sun direct rays from the sun all year and tend to be all year and tend to be warmer. Areas at higher warmer. Areas at higher latitudes tend to be latitudes tend to be colder – think Antarctica.colder – think Antarctica.

Latitude and TemperatureLatitude and Temperature

The SeasonsThe Seasons

• Many areas of Earth Many areas of Earth experience 4 distinct experience 4 distinct seasons. The seasons. The seasons are based seasons are based on temperature and on temperature and length of day. In length of day. In some areas, some areas, However, it is However, it is determined by determined by amount of rainfall. amount of rainfall.

Four Seasons on EarthFour Seasons on Earth

Winter and SummerWinter and Summer

• Changes in seasons Changes in seasons are created by the are created by the Earth’s tilt. As one Earth’s tilt. As one pole tilts towards pole tilts towards the Sun, it creates the Sun, it creates warmer temps and warmer temps and longer days, what longer days, what we refer to as we refer to as summer.summer.

Winter and SummerWinter and Summer

• Also because of the Also because of the tilt, the Northern tilt, the Northern and Southern and Southern Hemispheres Hemispheres seasons are seasons are opposite each opposite each other. When it is other. When it is summer in the summer in the Southern Southern Hemisphere, it is Hemisphere, it is winter in the North.winter in the North.

Spring and FallSpring and Fall

• As the Earth orbits As the Earth orbits the Sun, there are the Sun, there are periods when the periods when the poles tilt neither poles tilt neither toward or away toward or away from the Sun. This from the Sun. This is Spring and Fall. is Spring and Fall. As the poles begin As the poles begin to tilt toward the to tilt toward the Sun, it is Spring.Sun, it is Spring.

Spring and FallSpring and Fall

• And as they tilt And as they tilt away, we have Fall away, we have Fall marked by shorter marked by shorter days and cooler days and cooler temps. Solar temps. Solar energy is energy is beginning to beginning to decrease.decrease.

Rainfall and SeasonsRainfall and Seasons

• In the tropics region, In the tropics region, those close to the those close to the equator, seasons are equator, seasons are marked by the amount marked by the amount of rainfall, brought on of rainfall, brought on by moist or dry air. In by moist or dry air. In India, seasonal winds India, seasonal winds bring heavy rains called bring heavy rains called monsoons from June monsoons from June through October. Here, through October. Here, Hurricane season.Hurricane season.

Stay tuned tomorrow for …Stay tuned tomorrow for …

Water on EarthWater on Earth

The EndThe End