👉 A fluid is a substance that takes the shape of its container while maintaining a constant volume, unlike gases which expand to fill any space and liquids which have a fixed volume but can change shape to fit their container. Fluids exhibit viscosity, the measure of a fluid's resistance to flow, which determines how easily it moves. Examples of fluids include water, oil, and blood, all of which demonstrate the ability to flow and maintain their shape in a given space. The behavior of fluids is governed by fundamental principles like Bernoulli's equation and the Navier-Stokes equations, which describe how they move and interact under various forces.
