Why do we have seasons?

It is a question that can make even the most experienced educator break out into a sweat – why do we have seasons?

Although the answer itself is fairly straightforward, the many misconceptions surrounding the seasons often mean that a demonstration involving models of the Earth and Sun is required to help students fully understand this topic.

Because we always get questions about the seasons, and we know that teachers do too, we decided to create an animated video that dives into this topic.

Key points

Key points covered in the video above are:

• Different hemispheres experience different seasons at the same time.
• The Earth is tilted by an angle of 23.4 degrees.
• Due to this tilt, at some positions in the Earth’s orbit around the Sun, one hemisphere (northern/southern) points towards the Sun while the other hemisphere (southern/northern) points away from the Sun.
• The hemisphere pointing towards the Sun receives more direct sunlight causing the temperatures to increase – that hemisphere experiences summer.
• The hemisphere pointing away from the Sun receives less direct sunlight and so the temperature drops – that hemisphere experiences winter.
• Autumn and spring occur when neither hemisphere points towards nor away from the Sun.
• Temperatures along the equator are fairly constant throughout the year because the amount of direct sunlight that falls on the equator is constant.
• Some of the other planets in our solar system experience seasons.

Common misconceptions

Students are not the only ones who have misconceptions about the seasons; many adults have the same misconceptions too.

Here are a few of the misconceptions that pop up during sessions with students and members of the public:

1. The Earth’s orbit is highly elliptical with the Sun noticeably off-centre.
2. We experience summer when the Earth is closest to the Sun and winter when it’s furthest from the Sun.
3. Both hemispheres on the same side of the Earth experience the same seasons at the same time. People living on the other side of the Earth experience the opposite season.
4. The Sun’s temperature changes throughout the year, which causes the seasons.
5. If they know the Earth is tilted, they think the tilt causes the Earth to be considerably closer to the Sun at some points in its orbit.