# Thermal Expansion of Liquids

on . Posted in Thermodynamics

Unlike solids, which typically exhibit noticeable thermal expansion, liquids generally have a higher coefficient of volume expansion, as they lack a fixed structure like solids.  The coefficient of volume expansion quantifies the change in volume per unit volume per degree change in temperature.

When a liquid is heated, its molecules gain kinetic energy and move more rapidly, resulting in an increase in the average separation between molecules.  This increased molecular spacing leads to an expansion of the liquid, causing an increase in its volume.

The coefficient of volume expansion varies for different liquids and is typically positive, indicating that most liquids expand when heated.  However, it is important to note that the expansion of liquids is generally smaller compared to that of solids.

Thermal expansion of liquids is important to consider in various applications, such as in the design and operation of thermal systems involving liquid flow, heat transfer, and storage.  Understanding the thermal expansion behavior of liquids is crucial for the proper functioning and integrity of systems, preventing issues such as pressure changes, leakage, or damage due to thermal stresses.

### Thermal Expansion of Liquids Formula

$$\Delta V = a_v \; V_i \; \Delta T$$     (Thermal Expansion of Liquids)

$$a_v = \Delta V \;/\; V_i \; \Delta T$$

$$V_i = \Delta V \;/\; a_v \; \Delta T$$

$$\Delta T = \Delta V \;/\; a_v \; V_i$$

Symbol English Metric
$$\Delta V$$ = volume differential $$in^3$$  $$mm^3$$
$$a_v$$ = volumetric thermal expansion coefficient $$in^3 \;/\; in^3\;F$$ $$mm^3 \;/\; mm^3\;C$$
$$V_i$$ = object initial volume $$in^3$$ $$mm^3$$
$$\Delta T$$ = temperature differential $$F$$ $$C$$