👉 A spreading fluid, also known as a viscous fluid or non-Newtonian fluid, is a substance that flows more easily when subjected to stress or external forces. Unlike Newtonian fluids like water, whose viscosity remains constant regardless of applied force, spreading fluids exhibit a change in viscosity based on the stress applied. This means that when a spreading fluid is initially at rest, it resists movement and has a high viscosity. However, when force is applied—such as during the spreading of paint, ketchup, or even blood—it becomes less viscous and flows more freely. This behavior is due to the internal structure of the fluid, often composed of particles or molecules that can rearrange themselves under stress, reducing resistance and allowing the fluid to spread more easily.
