Lesson Plan - Get It!
Why does the sun set? Where does it go? Where does it come from?
Have you watched the sun set or rise?
It can be a very beautiful sight. Our earth is a giant sphere, moving in a system of planets around the sun.
You cannot feel it, but the earth is constantly spinning, or rotating, on an axis. The earth's axis is a central point in the middle of the planet. The axis has a tilt, causing the earth to rotate at an angle.
It takes the earth 24 hours to make a complete rotation on its axis.
- Why do you think 24 hours is an important number?
This is how we organize time — by day and night, based on the rotation of the earth.
When it is daylight outside, we are facing the sun. At nighttime, we are facing away from the sun. If it is daytime in the United States, what time do you think it is halfway around the world?
If the United States is experiencing day, countries on the opposite side of the earth are experiencing night.
Our spherical earth spins on its axis once each day, causing day and night. It takes 24 hours to complete one spin, which is how we keep time. During that time, half of the earth receives light, while the other half is in darkness. Look at the image above.
- How might the angle of the earth impact the amount of sunlight on the earth's surface?
- Do you think the North and South Poles get the same amount of sunlight? Why or why not?
Now, make a prediction about sunlight at the North and South Poles. Write your prediction on a sheet of paper, and discuss it with a parent or teacher.
In the Got It? section, you will learn more about the cause of day and night on the earth.