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Earth Dances

The Earth revolves around the Sun every 365 days, and this is why our calendar has 365 days in a year. That means the Earth moves completely around the Sun one time each year. So why does the Earth orbit the Sun? Think of it like this:
The Earth is spinning around the Sun just like you would twirl a ball on a string. If the string breaks, the ball flies off. Why doesn't the Earth "fly off" into outer space? That is because of gravity. Gravity is a natural force that attracts objects to each other. The Sun and the Earth are held together by gravity, so even though the Earth is spinning around the Sun, it remains in orbit because of gravity. This is the same reason why all of the planets orbit the Sun and also why the Moon orbits the Earth. Gravity is like the string that holds the twirling ball.

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Orbit Song

Sing a song about the orbit times of the Earth and the Moon.



Gravity is the reason we keep our feet on the ground. We feel Earth's gravity pulling us down. Because the Moon is smaller than the Earth, there is less gravity. If you weigh 60 pounds on Earth, you would only weigh 10 pounds on the moon!

Earth's orbital path is created by two things: gravity and a sideways motion
The sun is on the left and the earth is towards the right.  The earth is orbitting the sun and the rounded orbital path is shown.  An arrow labeled 'Sideways Motion' points from the earth directly to the top of the page.  An arrow labeled 'Gravity' ponits directly from the moon towards the sun.

The Earth also has an axis, and it rotates on its axis every 24 hours. This is why there are 24 hours in a day. Revolution is when the Earth moves in a circle around the Sun, and rotation is when the Earth spins on its axis. Because the Earth rotates one time every 24 hours, at any point in a day, half of the Earth is facing the Sun and half of the Earth is facing away from the Sun. In North America, we have daytime when our continent is facing the Sun. North America has nighttime when our continent is on the side of Earth facing away from the Sun. So, when it is nighttime in North America, it is daytime in places on the other side of the Earth.

Agronaut Log LogoEntry 5: Can you find an example of a country that is experiencing nighttime when you are experiencing daytime? Record the country in your log. Write a paragraph about 1) what you are doing at 8:00am and 2) what a boy or girl your age in that country might be doing at that same moment.


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