Study reveals intense CO2 degassing process in magmas

The Okinawa Trough is a newly formed back-arc basin located in the outer margin of the continental shelf of the East China Sea. The submarine hydrothermal activities are widely developed in the Okinawa Trough. A typical feature ...

Why do champagne bubbles rise in a straight trajectory?

Here are some scientific findings worthy of a toast: Researchers from Brown University and the University of Toulouse in France have explained why bubbles in champagne fizz up in a straight line while bubbles in other carbonated ...

Electronic noses sniff out volatile organic compounds

Volatile organic compounds (VOCs) are chemicals emitted as gases that can have adverse health effects. They are often found in paints, pharmaceuticals, and refrigerants, among other common products, but they can also act ...

Preserving pine forests by understanding beetle flight

The mountain pine beetle is one of the main causes of tree mortality in the pine forests of North America. For example, the insect has killed thousands of acres of pine forest in British Columbia and Alberta, and as a result, ...

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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.

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