It often seems to rain endlessly in spring. Although rainy days are a nuisance, they are actually vitally important to all living things. Rain showers are part of the continuous movement of water between Earth’s surface and the atmosphere that is called the water cycle. The following will introduce you to the importance of water and the basics of the water cycle. This article includes an activity which is designed for students and parents to carry out together at home. It explores the water cycle through the construction of a terrarium.