Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.

Why does everything look flat even though the Earth is round? – Zayden, age 11, Corona, California

Ever since the ancient Greeks first made observations of the circular Moon and the skies, scientists have known that the Earth is a sphere. We’ve all seen beautiful images of the Earth from space, some photographed by astronauts and others collected remotely by orbiting satellites. So why doesn’t our planet look round when we’re standing in a park or looking out a window?

The answer is all about perspective. Humans are pretty tiny creatures living on a really large sphere.

An average adult is between 5 feet and 6 feet 6 inches tall (1.5 to 2 meters), and kids are smaller. Imagine you’re a circus acrobat standing on a ball that’s about 3 feet (1 meter) wide. From on top of the ball, you would see it curving away from your feet........

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