Why do the season Change?

We have summer and winter weather because of the way the earth spins around the sun on a tilted axis. The axis is what we call the line from the north Pole through the South Pole, and it tilts because of the combination of forces at work on the earth, from the pull of the sun and the moon.

This means that during part of the year the North Pole tilts nearer the sun, and at other times further away from the sun. When the Northern Hemisphere is turned to sun the countries north of the equator have their hot, summer weather, while the countries of the Southern Hemisphere, who are further from the sun at this point, have their winter weather.