Read the "Solids, Liquids, and Gases" section. Note the differences between these three phases of matter on both the microscopic and macroscopic levels. Solids, like wooden blocks, have definite shape and definite volume, and the particles are ordered and close together. Liquids have definite volume and indefinite shape, meaning they take on the shape of the container. Imagine the differences between iced tea in a pitcher versus in a glass. A liquid's particles are less ordered, but still relatively close together. Gases, such as the air inside balloons, have indefinite shape and indefinite volume and their particles are highly disordered.