Nanobubbles provide pathway to build better medical devices

Researchers from the University of Sydney Nano Institute and School of Chemistry have revealed that tiny gas bubbles—nanobubbles just 100 billionths of a meter high—form on surfaces in unexpected situations, providing ...

Making an object invisible under fluid flow

The invisibility cloak is an artifact that can make the wearer transparent, rendering it undetectable to observers outside. Perhaps, one of the most well-known examples is the invisibility cloak possessed by Harry Potter ...

Water nanoproperties as a key factor for sanitation

Living organisms, viruses, and technological devices, have water layers between their cells or parts and can die or stop working when dehydrated. But why water and not any other fluid? What makes water unique under such conditions ...

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Fluid

In physics, a fluid is a substance that continually deforms (flows) under an applied shear stress, no matter how small. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids.

In common usage, "fluid" is often used as a synonym for "liquid", with no implication that gas could also be present. For example, "brake fluid" is hydraulic oil and will not perform its required function if there is gas in it. This colloquial usage of the term is also common in medicine and in nutrition ("take plenty of fluids").

Liquids form a free surface (that is, a surface not created by the container) while gases do not. The distinction between solids and fluid is not entirely obvious. The distinction is made by evaluating the viscosity of the substance. Silly Putty can be considered to behave like a solid or a fluid, depending on the time period over which it is observed. It is best described as a viscoelastic fluid. There are many examples of substances proving difficult to classify. A particularly interesting one is pitch, as demonstrated in the pitch drop experiment currently running at the University of Queensland.

This text uses material from Wikipedia, licensed under CC BY-SA