Although siphons are simple in appearance, they can provide opportunities for all kinds of discoveries and manipulations when several are connected together or when other materials are connected to them. In the process of getting water to move through a simple system and, later, through a more complex system of connected siphons, children can puzzle over some of the properties of water and air. In most situations, children ignore the presence of air because it is invisible. But when working with siphon systems, children will begin to discover that air occupies space and can exert a force. Similarly, they will discover how water pressure acts as water moves through a system of connected bottles or when water is used to inflate a balloon. Throughout this Siphon Systems project, children will be able to exercise their scientific thinking when trying to sort out and analyze what is happening as water flows through bottle systems. The overall goal of this exploration is to provide opportunities for children to become better acquainted with properties of water and air and to refine their skills in the manipulation of materials. They can also develop good habits of mind when they report on their discoveries and talk about what they think is happening. They can practice generating questions and attempt to find answers to these questions. These abilities and habits of mind are a necessary foundation for extended inquiry in school and are generally useful as life skills in adulthood. More generally, the goal of theExplore It! program is to preserve the innate curiosity and wonder of children.