1、Why is the sky blue during the day?
2、Why do we experience seasons on Earth?
3、Why is the ocean salty?
4、Why do stars twinkle at night?
5、Why does ice float on water?
6、Why do plants need sunlight to grow?
7、Why is the Earth round?
8、Why do we have tides in the oceans?
9、Why is the moon sometimes visible during the day?
10、Why does the Sun appear to rise and set every day?