👉 Fluid, in the context of physics and chemistry, refers to a substance that exists in all three states of matter: solid, liquid, and gas, but can also be described as a mixture or solution where components mix at a molecular level without forming distinct phases. This term encompasses fluids like water, oils, and gases, which can flow and change shape while maintaining their chemical composition. The term "fluid" also describes liquids, which have a definite volume but take the shape of their container, and gases, which have neither a definite volume nor shape, expanding to fill any container they occupy. The behavior of fluids is governed by principles such as viscosity, surface tension, and fluid dynamics, which explain how they interact with their environment and each other.
