A diagram explaining the cause of the season shows the earth and its orbit around the sun. What is the main factor in how the changing seasons occur?
tilt of axis
A line between the earth north pole and south pole is inclined to the orbital plane of the earth around the sun at about 23 degrees. Therefore at summer solstice in June the north is getting more sun and it is directly overhead at noon if you are about 23 degrees above the equator (tropic of Cancer, summer solstice), a quarter year later the sun is hitting the earth right at the equator (fall equinox), another quarter around and the south is getting the sun, tropic of Capricorn below the equator, then in spring another equinox as we head for summer. ( try Sea Scouts :)
tilt of axis
The main factor in how the changing seasons occur is the tilt of the Earth's axis. To understand this, let's first explain the Earth's orbit around the sun.
The Earth goes around the sun in an elliptical path called its orbit. This orbit is not perfectly upright; instead, it is tilted relative to the plane of the Earth's equator. This tilt is known as the Earth's axial tilt.
During the year, the Earth revolves around the sun, and the axial tilt remains constant. However, the orientation of this tilt in space determines the changing seasons.
Now, let's consider a diagram explaining the cause of the season with the Earth and its orbit around the sun. Imagine a circular or elliptical orbit with the sun at one of the foci. Within this orbit, draw a simple representation of the Earth as a sphere.
Next, draw a line or axis passing through the Earth from its North Pole to the South Pole. This line represents the Earth's axial tilt. The angle of this line relative to the orbital plane of the Earth gives us the axial tilt value.
To illustrate the changing seasons, create four different positions of the Earth along its orbit to represent the solstices and equinoxes:
1. Summer Solstice: Position the Earth in its orbit so that the Northern Hemisphere is tilted towards the sun. This will be at the highest point of the axial tilt. Label this position as the "June Solstice" or "Summer Solstice."
2. Fall Equinox: Move the Earth along its orbit to a point where neither hemisphere is tilted towards or away from the sun. This position represents the equinox, where the length of day and night are approximately equal. Label it as the "September Equinox" or "Fall Equinox."
3. Winter Solstice: Continue moving the Earth along its orbit until the Southern Hemisphere is tilted toward the sun, while the Northern Hemisphere is tilted away. This will be at the lowest point of the axial tilt. Label this position as the "December Solstice" or "Winter Solstice."
4. Spring Equinox: Finally, adjust the Earth's position to a point where no hemisphere is tilted towards or away from the sun. This represents the other equinox, where the length of day and night are approximately equal. Label it as the "March Equinox" or "Spring Equinox."
By observing this diagram, you can see that as the Earth orbits around the sun, different parts of the globe receive different amounts of sunlight at different times of the year due to the axial tilt. This variation in sunlight leads to the changing seasons.