Physical Properties of Liquid
Physical Properties of Liquids
Liquids have several unique physical properties that distinguish them from solids and gases. These properties are essential to understand the behaviour and applications of liquids in different scientific and industrial fields. Some important physical properties of liquid are discussed below-
Density
Density is mass per unit volume and is expressed in kilograms per cubic meter (kg/m³). Density of liquids is higher than gases but lower than solids. It is important for buoyancy, floatation, and sedimentation phenomena.
Viscosity
Viscosity is a property of liquid that resistance to flow. It is expressed in pascal-seconds (Pa·s). Liquids having high viscosity flow slowly, while those having low viscosity flow easily. Viscosity affects the pouring behaviour, spreadability and flow rate of liquids..
Surface Tension
Surface tension is surface phenomenon. It is the force that acts at the surface of a liquid, causing to behave like a thin elastic membrane. It is expressed in newtons per meter (N/m). Surface tension is responsible for droplet formation, capillary action, and the formation of liquid interfaces.
Capillary Action
Capillary action is the ability of a liquid to flow against gravity in a narrow space such as a thin tube. It happens due to the combined effects of surface tension and adhesion between the liquid and the tube walls. Capillary action is essential in plants for water transportation and in various microfluidic applications.
Boiling Point
The temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure is boiling point of that liquid. At this temperature, the liquid transforms into a gas (vapor) that means liquid starts to boil. The boiling point is expressed in units of degrees Celsius (°C) or Kelvin (K).
Vapour Pressure
Pressure exerted by vapour on the surface of liquid at a particular temperature is called vapour pressure. It represents the tendency of a liquid to evaporate. Liquids having high vapor pressures tend to evaporate more easily than those having low vapor pressures.
Volume Expansivity
It is the measure of change in volume of a liquid with temperature. Liquids generally expand when heated and contract when cooled.
Specific Heat Capacity
The amount of heat required to raise the temperature of one gram of a liquid by one degree (in Celsius or in Kelvin) is heat capacity. It is the ability of a liquid to store thermal energy.
Refractive Index
Refractive index is the measure of bending of a light ray when passing into liquid from another medium. It is crucial in optics and lens design.
