If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Middle school Earth and space science - NGSS

Course: Middle school Earth and space science - NGSS>Unit 2

Lesson 1: Seasons

Seasons

Earth's seasons are caused by its tilt and revolution around the sun. When a hemisphere points toward the sun, it's summer. When a hemisphere points away from the sun, it's winter. The two hemispheres always have opposite seasons. Created by Sal Khan.

Want to join the conversation?

• why does the north pole have constant daylight and the south pole has constient night time?
• The North Pole gets 24 hours of sunlight near the summer solstice. The North Pole gets 24 hours a darkness near the winter solstice.

The South Pole gets 24 hours of sunlight near the winter solstice. The South Pole gets 24 hours a darkness near the summer solstice.

It works this way because the during summer, the North Pole is tilted toward the sun and the South Pole is tilted away from the Sun. Oppositely, during winter the North Pole is tilted away from the sun and the South Pole is tilted toward the Sun.

Where you live, you have day and night cycles due to the rotation of Earth. As Earth turns, your city is either in or out of sunlight based on the direction that Earth is facing. This isn't possible at the North and South Poles because the poles are the surface expression of Earth's axis of rotation. When you are at the North or South Pole Earth is still rotating, but because you are at the point that Earth rotates around Earth's rotation doesn't take you anywhere.
• Does large amounts of mass create gravity?
• Yes, everything has gravity. It is a very weak force,so, besides the earth and sun,you don't notice it in everyday life. when i say every thing has gravity, i mean EVERYTHING. From tiny little atoms, to everything that has existed, is existing, and will exist altogther. So yes, large masses have gravity.
• How come in the diagram of the 4 seasons, If the rays are hitting different angles how come at the bottom it's not always winter
• Because of the earth's tilt on its axis sometimes the bottom is actually tilted closer/towards the sun which is why it's not always winter.
• Do the solstices and equinoxes occur on the same day each year?
(1 vote)
• Nope, even though they occur at the same spots in Earth’s orbit around the sun, they don’t always line up with the same day in our calendars. For instance, the summer solstice will be on June 21st in 2022 and 2023, but June 20th in 2024.

I hope this helps! :)
• why does this happen
• Why does the moon orbit the earth and why does the earth orbit the sun
• its all because of the gravitational pull, I don't know how tho sry
• why does the north pole have constant daylight
• The north and south poles have constant daylight in the summer and constant darkness in the winter because of the Earth's tilt. They aren't rotated to dark side of the Earth in the summer, or the light side in the winter.
• Why do the phases move by the seasons?