Have you ever wondered why we have day and night? It’s all because of how our planet, Earth, moves! Earth spins around like a top, and this spinning is called rotation. But what does it spin around? It spins around an invisible line called an axis. Imagine a stick going through the Earth from the North Pole to the South Pole. That’s the axis, and it’s tilted a little bit, at an angle of 23.5 degrees.
As Earth rotates, different parts of it face the Sun. When your part of the world is facing the Sun, it’s daytime for you because the Sun lights up the sky. But when your part of the world turns away from the Sun, it’s nighttime, and the sky gets dark. This is why we have a cycle of day and night.
It takes Earth 24 hours to make one full spin on its axis. That’s one whole day! This means every day, we get to see the Sun rise in the morning and set in the evening, giving us both day and night.
Did you know that if you could stand at the North Pole, you would see the Sun moving in a circle in the sky? It would never set for half the year, and then it would be dark for the other half!
Now you know why we have day and night. Isn’t it amazing how the Earth’s rotation makes this happen every single day?
Shadow Tracking: On a sunny day, go outside with a piece of chalk and a friend. Stand in one spot and have your friend trace your shadow on the ground with the chalk. Come back every hour and trace your shadow again. Notice how your shadow changes throughout the day. Discuss with your friend why you think the shadow moves and changes size. How does this relate to the Earth’s rotation?
Sunrise and Sunset Journal: For one week, keep a journal of the time the Sun rises and sets each day. You can ask an adult to help you find this information or observe it yourself if you can. Write down the times and draw a picture of what the sky looks like at sunrise and sunset. At the end of the week, look at your journal and see if you notice any patterns. Why do you think the times change slightly each day?
Day and Night Globe Activity: Use a globe and a flashlight to model how the Earth rotates to create day and night. Have an adult help you find your location on the globe. Shine the flashlight on the globe to represent the Sun. Slowly spin the globe and watch how different parts of it move into the light and then into the dark. Can you find out when it’s daytime and nighttime in other parts of the world? Try to explain what you see to a family member or friend.
Here’s a sanitized version of the transcript:
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Why do we experience day and night? One way the Earth moves is by spinning on its axis. An axis is an imaginary line that runs through the Earth’s center at an angle of 23.5 degrees. This spinning movement on its axis is called rotation. As it rotates, part of the Earth is facing the Sun, and this part is lit up and experiences daytime. At the same time, the opposite side of the Earth is facing away from the Sun, which is in darkness and experiences nighttime. It takes the Earth 24 hours to complete one rotation. The repeating rotation of the Earth is why we experience the daily pattern of day and night.
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