Day and Night3.8C; 5.8C

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Why do we only see the sun part of the time?• Sometimes we go outside and the

sky is bright. We are able to see everything around us!

• Other times the sky is dark and it is hard to see across the street.

• What makes this difference? Why is the sky bright some of the time and dark the rest of the time?

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Day and Night

The reason we can’t see the sun all the time is because the Earth is constantly rotating, or spinning, on its axis.

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An axis is an imaginary line that goes through the Earth from the North Pole to the South Pole.

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How long do you think it takes the Earth to rotate once on its axis?

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It takes the Earth 24 hours to make one rotation on its axis.

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Day and night are caused by the rotation of the Earth on its axis.

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The side of the Earth facing the sun experiences daytime.

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The side facing away from the sun has night.

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This day/night cycle takes 24 hours or 1 day!

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Sunrise and sunset are part of the Earth’s day/night cycle.

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The sun rises in the East.

The sun sets in the West.

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The Earth rotates counter-clockwise, or to the East.

That’s why the sun appears to move from East to West in the day sky! 11

The sun doesn’t really move—it just appears to because the Earth is moving!

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7:00 a.m.

8:00 a.m.

9:00 a.m.

11:00 a.m.

12:00 p.m. or noon

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