Why do we have seasons?
Quick answer from Eartha
Seasons happen because our planet is slightly tilted as it travels around the sun. When your part of the world leans towards the sun, you get more direct sunlight and warmer weather, that's summer. When it leans away, sunlight is weaker and spread out, and that's winter. It takes a whole year to go all the way around.
The longer story
Our planet doesn't stand up perfectly straight. It's tilted a little on its axis, like a spinning top that's leaning slightly to one side.
As the planet travels around the sun over a whole year, that tilt means different places lean towards or away from the sun at different times. When your home leans towards the sun, sunlight hits more directly and days feel warmer, that's summer.
When your home leans away from the sun, sunlight arrives at a shallow angle and spreads out over a bigger area, making it feel weaker and cooler, that's winter. Spring and autumn happen in between, as the tilt shifts gradually.
This is also why the seasons are opposite in different parts of the world. When it's summer in Australia, it's winter in places like the United Kingdom, because they're leaning away from the sun while we're leaning towards it.
Try this at home: torch and ball seasons
- Shine a torch straight onto a ball to make a small, bright circle of light.
- Now tilt the ball slightly so the torchlight hits it at an angle.
- Notice how the light spreads out and looks dimmer, just like winter sunlight.
Words to know
- axis
- An invisible line through the middle of the planet that it spins around.
- tilt
- To lean a little to one side instead of standing straight up.
- orbit
- The path a planet travels as it goes around the sun.
For grown-ups: what is my child learning here?
Age band: Ages 5-8
Curriculum link: Australian Curriculum v9 Science, Year 3 to Year 4, Earth and Space Sciences strand: exploring Earth's rotation and orbit and how they affect observable phenomena.
The concept: The child is learning that the tilt of the planet, not distance from the sun, causes the seasons.
More classroom ideas are on our teachers page, and safety notes for families are on for parents.
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