5 Nature's Patterns

World Book's Learning Ladders Nature's Patterns

该页暂无翻译

Day and night There are many patterns in nature that we can see every day. We can see the pattern of day and night. During the day, the sun moves through the sky. When the sun sets, the day ends and night begins. Earth travels around the sun. As it does so, it spins like a top. This spinning is what causes day and night. It's a fact! Between September and March, it is nearly always daytime at the South Pole. At sunrise, the sun rises into the sky.

At midday, the sun is at its highest point in the sky. People cast shadows in sunlight. The shadows move just like the people. At sunset, the sun seems to disappear beneath the ground. Daylight has ended. On cloudy days, the sun is hidden above the clouds. Cloudy days are often cooler because sunlight bounces off the clouds and goes back into space.

The moon The moon is the brightest object in the night sky. It is a huge rock that travels around Earth. Because of this movement, the moon seems to change shape over time. These changing shapes are called the moon's phases. It's a fact! If you walked on the moon, you would weigh only about 1/6 as much as you do on Earth. You could jump really high! When the moon is completely dark, it is called a new moon. A crescent moon can be seen a few days after a new moon. As the moon becomes more and more full, it is said to be waxing.

When the moon is completely full, it is called a full moon. A full moon comes about 14 days after a new moon. As the moon becomes less and less full, it is said to be waning. The moon continues to disappear. Soon the moon will be dark again. The moon is extremely hot during the day and very cold at night. Astronauts wear space suits that protect them from the heat and the cold.