# Thermal expansion of liquids

Do you want to determine the coefficient of thermal expansion of your liquid samples? Calnesis carries out this type of study by performing very precise density measurements as a function of temperature.

## What is the thermal expansion of liquids ?

During a temperature variation, the volume of liquids changes: they contract or expand. The coefficient of thermal expansion of liquids is a parameter which makes it possible to quantify this phenomenon. For the majority of liquids, this coefficient is of the order of 10-4/K: for each degree, the volume of the fluid increases by a few ten-thousandths of times its volume.

Special case: the volume contraction of water between 0 and 4°C

While almost all fluids expand with a rise in temperature, there is at least one exception: between 0 and 4°C, water contracts with the rise in temperature. Over this temperature range, its coefficient of thermal expansion is then negative.

## How it is measured ?

The coefficient of thermal expansion is not measured directly with a device. Its determination is carried out by calculation from precise measurements of densities carried out at several temperatures.

Coefficients of thermal expansion are determined as a function of temperature from density values ​​using the equation opposite.

At Calnesis, the density measurements allowing the determination of the evolution of the volumetric thermal expansion coefficients of liquids are carried out with a very precise vibrating tube densimeter: the Anton Paar DMA 5000M. This device allows the measurement of density with an accuracy of 0.000001 g/cm3 over a temperature range between 0°C and 100°C.

The coefficients of thermal expansion of liquids are much greater than those of solids.
Clément Duprat, Work-study engineer, Calnesis

Other measurements
Thermal expansion measurement of solid samples according to the temperature
Measurement of the density of solid samples using different technics.
Measurement of the density of liquid samples over a wide temperature range.