A liquid is one of the fundamental states of matter, characterized by its ability to flow and take the shape of its container while maintaining a constant volume. Liquids have a definite volume but no fixed shape, which distinguishes them from solids (which have both a definite shape and volume) and gases (which neither have a definite shape nor a definite volume).
Key properties of liquids include:
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Fluidity: Liquids can flow and move, which allows them to fill the shape of the container they are in.
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Incompressibility: While they can be slightly compressed, liquids are generally considered incompressible under normal conditions, meaning their volume remains relatively constant even under pressure.
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Surface Tension: Liquids exhibit surface tension due to the cohesive forces between molecules at the surface, which creates a "skin" effect that allows certain objects to float or resist being penetrated.
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Viscosity: This refers to the resistance of a liquid to flow; different liquids have different viscosities, which can affect how quickly they pour or spread.
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Density: The density of a liquid is defined as its mass per unit volume, and it can vary based on temperature and pressure.
Examples of common liquids include water, oil, alcohol, and mercury.