👉 A fluid is a substance that takes the shape of its container while maintaining a constant volume, but unlike gases, it does not expand to fill all the space available. Instead, fluids flow and can move from areas of higher pressure to areas of lower pressure. This characteristic arises because the particles in a fluid are close enough to interact but not so tightly that they form a solid structure, allowing them to slide past each other. Examples of fluids include water, oil, and blood. The term "fluid" can also refer to a state of matter that can flow, such as lava or molten rock.
