Have you ever stepped out on a blazing hot day or walked through a snowstorm and wondered why we have seasons? Seasons on Earth are created by tilt and rotation and this lesson will help you learn why we have them.
It’s All About the Tilt
Have you ever looked at a globe? If you have, you may have noticed that the north and south poles don’t point straight up and down. In fact, the whole globe is tilted. It’s this tilt that is the main cause of the seasons.
When a basketball player spins a ball on his finger, the ball spins around with the bottom pointing down and the top pointing up. The basketball player’s finger is holding the ball in place.
The Earth has an imaginary finger that it spins around called the axis. The axis is the imaginary line or finger that the Earth spins around. But unlike the basketball, the axis is not right at the bottom of the Earth. If the Earth was a clock face, the north pole would point toward 1 o’clock and the south pole would be pointing to 7 o’clock.
Leaning Toward the Sun
So now that you can imagine the Earth spinning at a tilt and not like a basketball on a finger, imagine that the Earth rotates around the sun in a giant circle called an orbit, kind of like a big fly buzzing around your head. The tilt of the Earth stays the same direction, so when the Earth is to the far left of the sun, the north pole is tilted towards the sun, so the northern half, or hemisphere, is having the warmest season called summer. Now, since the north pole is tilted closer to the sun, the south pole is tilted away, making it the coldest season, winter, there because the sun is the farther away.
in summer, and the lower right picture has the U.S. in winter.
Since the Earth is round, some parts are closer to the sun.
The equator is the fattest part of the globe and goes around the middle like a big imaginary belt. With the tilting poles, the equator stays at the same distance from the sun, which is why the seasons don’t change there. Winter and summer have the same weather. Winter at the north or south poles is freezing cold and constantly dark and the summers are warm with constant sunlight.
The Earth experiences different types of climate at different times of the year because of the seasons. We have seasons because the Earth is tilted on its axis as it rotates around the sun. What part of the Earth is tilted toward the sun determines the seasons, and the equator is always the closest part of the Earth to the Sun.