The sun shines on us. It gives us light and heat. It makes everything grow. It gives the earth life.
The earth turns round itself. As it turns, we have day and night. It's bright by day and dark by night.
The earth also travels round the sun in an orbit. As it travels, we have four seasons. It is hot in summer and cold in winter. the days are long in summer and short in winter. In spring it is warm and the days are getting longer. In autumn it is cool and the days are getting shorter.