We have seasons because Earth is tilted. As Earth goes around the sun in a year, the tilt points our part of the world toward the sun for half the year and away for the other half. Toward the sun it is summer. Away it is winter.
Peabody: Hi, I am Peabody! Spring, summer, fall and winter. Why does the weather change through the year? Some people think Earth gets closer to the sun in summer. That is not it.
Crumb: I am Crumb! The real reason is the tilt. Earth spins like a top, but it leans a little to one side. It always leans the same way.
Peabody: Earth also travels around the sun. One trip takes one year. Because of the lean, different parts of Earth point toward the sun at different times.
Crumb: When your part of Earth leans toward the sun, the sunlight hits more directly. Days get longer and warmer. That is summer!
Peabody: When your part leans away, the sunlight is more spread out. Days get shorter and colder. That is winter.
Crumb: Here is a fun fact. When it is summer in the north, it is winter in the south. In Australia, they have a warm December!
Crumb: Here is a recap! Earth is tilted and goes around the sun once a year. Leaning toward the sun brings summer. Leaning away brings winter. It is the tilt, not the distance!
Quiz: five questions
Tap an answer. Stuck? Tap the hint. Nothing is scored or saved.
Question 1 of 5
What causes the seasons?
The words
tilt
a lean to one side
season
one of the four parts of the year
orbit
the path Earth takes around the sun
axis
the line Earth spins around
equator
the imaginary line around the middle of Earth
Make it: put the explainer in order
Tap the scenes in the order they happen. Which comes first?
Try it without a screen: Lamp and ball seasons
You need: a lamp with no shade, an orange or ball, a pencil, a dark room.
Push the pencil through the orange to make an axis. Tilt it a little.
Put the lamp in the middle of the room. It is the sun.
Walk the orange around the lamp, keeping the pencil pointing the same way.
Stop at four places. Notice when the top half is lit more and when it is lit less.
For the grown-up
This explainer replaces the common idea that seasons come from Earth being closer to the sun with the right one: the 23.5 degree tilt. A lamp and an orange is the classic demonstration. Earth is actually closest to the sun in early January. Nothing here is saved or shown to anyone.