👉 A fluid, in the context of physics and engineering, is a substance that takes the shape of its container but not its volume. This characteristic fluid behavior is primarily due to the cohesive and adhesive forces between its molecules, which can be liquids, gases, or even certain solids like ice. Liquids are incompressible and have a definite volume but can flow, while gases are compressible and expand to fill any container. The key affecting fluid properties include temperature, pressure, and the nature of intermolecular forces, which can significantly alter a fluid's viscosity, surface tension, and density, impacting its behavior in various applications from hydraulic systems to atmospheric phenomena.
