In contrast, liquids deform easily when stressed and do not spring back to their original shape once the force is removed because the atoms are free to slide about and change neighbors—that is, they flow so they are a type of fluid , with the molecules held together by their mutual attraction. When a liquid is placed in a container with no lid on, it remains in the container providing the container has no holes below the surface of the liquid! Because the atoms are closely packed, liquids, like solids, resist compression.
Atoms in gases are separated by distances that are large compared with the size of the atoms. The forces between gas atoms are therefore very weak, except when the atoms collide with one another. Gases thus not only flow and are therefore considered to be fluids but they are relatively easy to compress because there is much space and little force between atoms.
When placed in an open container gases, unlike liquids, will escape. The major distinction is that gases are easily compressed, whereas liquids are not. We shall generally refer to both gases and liquids simply as fluids , and make a distinction between them only when they behave differently.
Skip to main content. Fluid Statics. Search for:. What Is a Fluid? Learning Objectives By the end of this section, you will be able to: State the common phases of matter. Explain the physical characteristics of solids, liquids, and gases. Describe the arrangement of atoms in solids, liquids, and gases. Matter most commonly exists as a solid, liquid, or gas; these states are known as the three common phases of matter.
We can describe fluids as something that can flow as a result of a pressure differential between two points. Liquids, in the case of liquids, are a subset of liquids. It is incompressible liquids. Examples of fluids are as follows water, honey, air, mercury, gasoline and etc. Click to rate this post!
Liquid vs. Gas Note that there are two separate terms that we are talking about here. Liquid and fluid. Fluid is a generic term, including liquids and gases as species. Water, air, and steam are fluids. A gas on the other hand, is compressible and expands to fill any volume containing it. Why is a liquid incompressible? The main difference between the study of hydrodynamics and the study of aerodynamics is the property if incompressibility.
Hydrodynamic properties are generally incompressible while aerodynamic properties are compressible. Consider the following argument. Measuring the speed of sound in a medium will give a measure of compressibility of that medium. Fluids cannot sustain a shear force, i.
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