This document discusses the properties of solids, liquids, and gases. It defines a material as anything made up of tiny particles and explains that a material's properties tell us something about what it is like. Solids have tightly packed particles that hold their shape, while liquids have less tightly packed particles that flow and take the shape of their container. Gases have particles with lots of room to move that spread out and fill all available space. An example given is water, which can be a solid (ice), liquid (water), or gas (steam) depending on temperature.