Every evening, Minjun watches the sun go down. One night, he asked his sister Yuna, "Where does the sun go at night? Does it move around the Earth?"
Yuna took Minjun to a dark room and turned on a flashlight. "This light is the sun," she said. "This small globe is our Earth."
Yuna pointed the light at the globe. One side of the globe was bright, but the other side was dark. "It is day on the bright side, and it is night on the dark side," she said.
Then Yuna slowly turned the globe, and Korea moved from the bright side to the dark side. "The Earth turns like a spinning top," she said. "It makes one full spin every day. The sun does not move around the Earth. It only looks like it moves because we spin."
Minjun nodded and smiled. "So when it is night in Korea, it is day on the other side of the world." Before bed, he looked at the dark sky and waved to the children far away.