Seasons SC.8.E.5.9 Explain the impact of objects in space on each other, including: 1. The Sun on the Earth, including seasons and gravita>onal a?rac>on 2. The Moon on the Earth, including phases, >des, and eclipses, and the rela>ve posi>on of each body. Essen>al Ques>ons: 1. Why is it important for the Earth to rotate and to revolve around the Sun? 2. How does the >lt of the Earth affect seasons?
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Seasons BrainPOP!
I Do Length of a Day Right- hand Side The earth spins on an imaginary line that runs from the North to the South Pole. This line is called an axis. When a planet or other celes>al body spins on its axis, it is called a rota>on. We call the >me that it takes for the Earth to complete a rota>on a day.
The Earth s RotaCon The Earth rotates in a counterclockwise mo>on when you look down on the Earth from the North Pole. The rota>on is from east to west, this is the reason why the Sun rises in the east and sets in the west. As the Earth rotates, only half of the Earth is facing the sun. We call this day>me. The other half of the Earth is facing away from the Sun. That side of the planet is in the dark. We call that nighome.
Length of a Year As the Earth rotates on its axis, it is also revolving around the Sun. This is the Earth s revolu>on. The Earth completes one full trip or revolu>on around the Sun every 365.25 days. We call this length of >me a year. We have divided our year into 12 months, each las>ng 28 to 31 days. Comprehension Check: compare and contrast the terms rota>on and revolu>on.
It s Tilted! The Earth does not rotate straight up and down. The axis is >lted 23.5. Depending on where the Earth is in its revolu>on we could be >lted toward or away from the Sun. The >lt affects many condi>ons: Temperature Number of daylight hours Seasons
Tilt and Temperature The angle at which the Sun s rays strike the Earth changes as the Earth moves through its orbit. When the North Pole is >lted toward the Sun, we get more direct light. We are warmer. When the Earth is on the other side of the Sun and the North Pole is pointed away from the Sun, we have less direct light. We are cooler. ***The Earth does not change the direc>on of its >lt, it stays the same direc>on the Earth just changes loca>on.
Tilt and Daylight Hours All loca>ons of the Earth have an average of 12 hours of daylight. There is some varia>on with loca>on. The areas >lted toward the Sun have more hours of daylight. These areas travel a longer path through the lit part that others near the equator. The areas >lted away from the sun have less than 12 hours of light a day. These areas travel a shorter path through the lit part. Comprehension Check: What are the temperatures and amount of daylight in the pole >lted away from the Sun compared to the pole >lted toward?
Tilt and Seasons Seasons are characterized by temperature and weather trends. Near the equator the temperatures are almost the same year- round. At the poles there are large changes from winter to summer. As the Earth travels around the Sun, the area of sunlight changes There are 4 significant points in the revolu>on of the Earth that play a part in our seasons. They are the equinoxes and sols>ces.
Equinox/SolsCce Equinox: when the Sun shines equally on the Northern and Southern Hemispheres. September Equinox (Autumnal): sunlight shines equally at both poles. The beginning of Fall. March Equinox (Spring): half of each hemisphere is lit and sunlight is concentrated at the equator. The beginning of Spring. Sols>ce: the area of sunlight is at a maximum in one hemisphere and at a minimum in the other. December Sols>ce (Winter): the North Pole leans away from the Sun and is in complete darkness. The beginning of Winter. June Sols>ce (Summer): the North Pole leans toward the sun and is in complete sunlight and the South Pole is in complete darkness. The beginning of Summer.
We Do / CollaboraCve You Do Compare and Contrast: Autumnal and Spring Equinox Compare and Contrast: Winter and Summer Sols>ce Autumnal Spring Winter Summer
CollaboraCve You Do LeP- hand Side Common Misconcep2ons of Students Explain why the misconcep>ons are wrong. Cite evidence or draw diagrams to support your answers. 1. Seasons are caused by the Earth being closer to the Sun in the summer and farther in the winter due to Earth s ellip>cal orbit. 2. The Sun is not at the center of the Earth s orbit, therefore the earth is closer or farther away from the Sun at different >mes of the year. 3. The Earth s >lt brings it significantly closer to the Sun during the ho?est >me of the year. 4. The Sun wobbles on its axis like a top that is spinning. The seasons are caused by the wobble of the Earth on its axis.
Independent You Do LeP- hand Side 1. Why is it necessary for us to have a leap year every 4 years? 2. During summer in the Northern Hemisphere the north pole >lts toward the Sun. Despite this, there is s>ll a large temperature difference between the equator and the north pole. Explain why there is this difference in temperature.
Quiz Time!
Exit Ticket LeP- hand Side Essen>al Ques>ons: 1. Why is it important for the Earth to rotate and to revolve around the Sun? 2. How does the >lt of the Earth affect seasons?