👉 Fluid, often referred to as a liquid or a non-Newtonian fluid, is a substance that flows like a liquid but can also behave like a solid or even a gas under certain conditions. At rest, it has a defined volume but lacks the internal friction to flow easily like a gas. However, when subjected to stress or force, it can deform and flow more readily, similar to how a solid might deform under pressure. This unique property is due to the interactions between its molecules, which can form temporary bonds or networks when stressed. Examples of fluids include blood, which carries oxygen and nutrients; ketchup, whose consistency changes when squeezed; and even certain types of paint or mud. The behavior of fluid can be described by various models, such as the Bingham plastic model for materials that behave like solids until a certain stress threshold is reached, or the power-law model for shear-thinning fluids like ketchup.
