🌍 Day, Night and the Seasons

Why does night follow day? Why is it warm in summer and cold in winter? The answer is hidden in the movements of our Earth. Let’s find out together!

The Earth spins around its own axis. This is called rotation. One full turn takes 24 hours. The side facing the Sun has day, and the side turned away has night. As the Earth spins, the tiny child goes from day into night.

We spin with the Earth, so the Sun seems to walk across the sky. It rises on one side in the morning, climbs high at midday and sets on the other side in the evening. It is not the Sun that moves. It is the Earth.

The Earth also travels around the Sun. This is called its orbit. One full trip takes about 365 days: one year. Rotation and orbit are two different movements.

A very common mix-up: “Summer is when the Earth is closer to the Sun.” Wrong! The Earth is closest to the Sun in early January, about 147 million kilometres away. It is furthest in early July, about 152 million kilometres. The difference is tiny. And January is cold in the Northern Hemisphere. Distance is not what causes the seasons.

The real cause: the Earth’s axis is tilted (by about 23.5 degrees), and as the Earth orbits, the axis always points the same way. In June the Northern Hemisphere leans towards the Sun: it is summer there. In December it leans away from the Sun: it is winter there. When it is summer in the north, it is winter in the south.

The tilted axis changes the angle at which sunlight hits the ground. When light hits the ground straight on, it falls on a small patch and that patch gets very warm. When light comes in slanted, the same light spreads over a big patch, so everywhere warms up less. In summer the days are longer too.

If the axis were not tilted, sunlight would arrive at the same angle all year round. Then there would be no seasons. The seasons come from the tilted axis and the trip around the Sun working together.

Summary: Rotation gives us day and night, and orbit gives us the year. The seasons come not from distance but from the Earth’s tilted axis. Straight light warms a lot, slanted light less. Now try it in Earth Spins!