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.
This demonstration shows the very unusual property which water has of expanding when it freezes. In the liquid state water molecules can pack more closely together than in the crystal structure of ice. This means the ice is less dense and so takes up more space than the liquid. It might be worth emphasising to the students that this is an unusual property and most substances become more dense as solids.