Unlike most world maps would have us believe, the Earth is actual tilted at a 23 degree angle as it rotates in place. This slight, and I mean slight, tilt has a big impact on what happens on the Earth’s surface. In some cases it will result in hotter areas and colder areas of the Earth over the course of its movement around the son. Because the sun takes so long to revolve around the sun (365 days), this results in changes in climate on Earth. This is the reason that most of the areas on Earth see four unique seasons.
You will find sheets that look at how seasons are created, solar and lunar eclipses, and how the Earth makes revolutions around the sun.