A significant part of aeronautical science is a branch of dynamics called aerodynamics, which deals with the motion of air and the way that it interacts with objects in motion, such as an aircraft.
When you pour a liquid from one container to another, the liquid takes the shape of the container. The volume of the liquid is the same. The properties that solids and liquids share are that they both have definite volume.
Water is the only common substance that is naturally found as a solid, liquid or gas. Solids, liquids and gases are known as states of matter. Before we look at why things are called solids, liquids or gases, we need to know more about matter.