The Seasons

The reason for the seasons…. e There are three reasons earth has its seasons: it has a 23.5 degree tilt, it rotates on an orbit, and its North Pole always points in the same direction. YOU NEED ALL THREE FOR THE SEASONS TO OCCUR!!

Reason # 1 : Have you ever wondered why?? e… the Earth on a globe is tilted? e Earths Tilt ­ The earths axis is not straight up and down, instead it leans at a degree angle.

Earths Axis e Axis of rotation- An imaginary line going from the north pole to the south pole. The earth spins on this.

The Earths tilt eBecause the Earth is tilted at a 23.5 degree angle, it has different amounts of sun hitting each section. Notice that the Northern Hemisphere has much more sun light.

Indirect vrs. Direct sunlight e The area of the Earth that receives the most direct sunlight experiences summer. e The area of Earth that receives indirect sunlight experiences winter. e The area that has the sunlight distributed evenly experiences either fall or spring.

Summer eIn the Northern Hemisphere the sun is directly hitting it during June, so it is summer. eWhat season is it in the Southern Hemisphere in June?

Winter eDuring December, in the Northern Hemisphere, the sun is hitting at an angle, so it is winter. eCan you tell where it is winter on these globes?

The suns angle eBecause the Earth is on an angle, the sun sits lower in the sky during the winter. Because of this Earth receives less daylight and the days are shorter.

Summer eDuring the summer the sun is much higher in the sky so the days are much longer and warmer. The more sun you have the warmer you are!

Reason #2 : Earths orbit or revolution. eWithout Earth orbiting the sun, there would not be different seasons. Take a look.

As the Earth Revolves eAs Earth revolves around the sun, different parts of it are exposed to different amounts of sun.

eIf the Earth did not revolve around the sun, it would stay one season all the time. eIf the Earth did not revolve around the sun, what season would it always be in the US?

Reason #3 eThe North Pole is always pointing in the same direction, towards Polaris (The North Star).

Sooo…. eSince the axis is always pointed towards Polaris, it will not tip back around toward the sun.

Direct sunlight Notice that the northern axis is pointed toward the sun. Notice that the southern axis is pointed away from the sun. Notice that neither axis is point toward or away from the sun.

eWhat would happen if the Earth wobbled on its tilt?

What about Spring and Autumn? eWhy do we experience Spring and Autumn?

We experience Spring and Autumn because as the Earth moves around the sun, the axis does not point toward the sun at all. So the angle of the of the sun is distributed evenly across Earth.

Equinoxes eEquinoxes : Mark an equal amount of day and night in both hemispheres. The Earths axis is not pointed toward the sun, so the Earth is receiving an equal amount of sunlight throughout. eNorthern hemisphere: eSpring Equinox: About March 20: eAutumnal Equinox: About September 22

Solstices e Winter solstice: e December 22 in the Northern Hemisphere. This marks the shortest day of the year when the Northern hemisphere is receiving the least amount of direct sunlight. e Summer solstice: e June in the Northern Hemisphere. This marks the longest day of the year when the Earth is receiving the most amount of direct sunlight.

Did you know??? e That the sun is actually closer to Earth in the winter than in the summer? e It is…but only in the Northern hemisphere. e Because of the Earths elliptical orbit, the sun is actually closer to the Earth in the winter and farther away in the summer. e The Southern hemisphere is opposite.

The seasons have almost nothing to do how close the sun is to the Earth!!! eIt is all about the angle!

The Equator eCountries near the equator do not experience the four seasons the same way we do in Utah. eEcuador is near the equator and it stays warm all year because the angle of the sun stays the same.

Earths Equator eThe Equator is an imaginary line drawn around the center of the Earth. It is of equal distance from the North and South Poles.

Rotation Versus Revolution e Rotation: When a planet or moon turns all the way around or spins on its axis one time. e Revolution: The circling of one object around another object in space. A planet revolves around the sun. A moon revolves around a planet. Rotation, revolution

Orbit eAn orbit is the path that a planet travels as it goes around the sun. eWithout our orbit we would not have the different seasons.

Las estaciones

Las razones de las estaciones La razón numero uno. (#1) La tierra tiene una inclinación de 23.5 grados grados

eLa tierra está rotando en su propia eje en un ángulo de 23.5 grados.

La razón numero dos. (#2) eLa tierra está orbitando el sol. El equinoccio otoño El 22/23 de septiembre El equinoccio primavera El 20/21 de marzo El solsticio de verano El 22/22 de junio El solsticio de invierno El 22/22 de diciembre

La razón numero tres (#3) eEl eje norte siempre está señalado a la estrella Polar.

Los equinoccios e El equinoccio es la época del año en que, por hallarse el Sol sobre el ecuador. e Los días y las noches son iguales en toda la Tierra.

Los solsticios eEs aquel instante en que el Sol se halla en uno de los dos trópicos. eDurante el solsticio de invierno, el día dura menos que la noche. eDurante el solsticio de verano, el día dura más que la noche.

Los equinoccios y solsticios El equinoccio otoño El 22/23 de septiembre El equinoccio primavera El 20/21 de marzo El solsticio de verano El 22/22 de junio El solsticio de invierno El 22/22 de diciembre

Los hemisferios e El hemisferio norte es la mitad superior de la tierra. e El hemisferio sur es la mitad inferior de la tierra.

Los Polos El polo norte El polo sur

El ecuador eEl ecuador es el área alrededor del planeta que se encuentra a la misma distancia del punto que está más al norte y del que está más al sur en la Tierra.

El invierno eDurante el invierno los días son cortos y fríos. e El eje no está señalado al sol.

El invierno eHace frío. eEstá nevando.

La primavera eDurante la primavera ni el eje norte ni el eje sur está señalado al sol.

La primavera eHace fresco. eEstá lloviendo.

El verano eDurante el verano el eje está señalado al sol.

El verano eHace calor. eHace sol. eHace buen tiempo.

El otoño eDurante el otoño ni el eje norte ni el eje sur está señalado al sol.

El otoño eHace fresco. eHace viento