How does Temperature Change Viscosity in Liquids and Gases?

Updated by Reginald Davey 03/03/2023

A number of factors can influence viscosity in gases and liquids, which is an important consideration for material design. This article will discuss the effect of changing temperature on the viscosity of liquids and gases.


Image Credit: Akim Lakeev/


With an increase in temperature in a fluid, there is typically an increase in the molecular interchange as molecules move faster in higher temperatures. Viscosity typically decreases as temperature increases. Generally speaking, a fluid’s viscosity is related to how easily molecules can move in respect to one another.

Do Gases Have Viscosity?

The viscosity of gas increases with temperature. According to the kinetic theory of gases, viscosity should be proportional to the square root of the absolute temperature. In practice, it increases more rapidly.

Viscosity and Temperature in Liquids

Different liquids have different viscosities. For example, the viscosity of honey is much higher than that of water. Amongst fluids, gases have lower viscosities than liquids. Viscosity is measured using a viscometer.

In a liquid, there will be molecular interchange similar to those developed in a gas but also additional, substantial, attractive, cohesive forces between the molecules within a liquid (which are much closer together than those of a gas). Both cohesion and molecular interchange contribute to liquid viscosity.

The impact of increasing the temperature of a liquid is to reduce the cohesive forces while simultaneously increasing the rate of molecular interchange.

The former effect causes a decrease in the shear stress, while the latter causes it to increase. The result is that liquids show a reduction in viscosity with increasing temperature. With high temperatures, viscosity increases in gases and decreases in liquids; the drag force will do the same.

Impact of Increasing Temperature

The impact of increasing temperature is to slow down the sphere in gases and accelerate it in liquids. Considering a liquid at room temperature, the molecules are tightly bound together by attractive inter-molecular forces such as Van der Waal forces.

It is these attractive forces that are responsible for the viscosity since it is difficult for individual molecules to move due to being tightly bound to their neighbors.

The increase in temperature causes the kinetic or thermal energy to increase and the molecules become more mobile.

The attractive binding energy is reduced, and therefore the viscosity is reduced. If the liquid continues to be heated, the kinetic energy will exceed the binding energy and molecules will escape from the liquid and it can become a vapor.

Viscosity of Water at Different Temperatures

Water is the most abundant liquid on Earth and is used in multiple industrial and commercial processes. Knowledge of the viscosity of water at different temperatures is vital for the design of products and industrial machinery.

Water, being the most abundant and studied of all liquids, is a good starting place when learning about viscosity and how factors such as temperature can affect a fluid. At room temperature, water has a dynamic velocity of approximately 1.0 mPa/s. At around 375oC, this decreases to under 0.1 mPa/s.

Commercial Importance of Viscosity

Viscosity in a liquid or gas is a key parameter in the design of products as it is an important quality indicator for consumers. For instance, a thicker liquid may be thought of as superior in quality to a thinner one.

In the food industry, viscosity measurements are an integral part of the production process to maximize cost-effectiveness and efficiency. In construction, the viscosity of concrete governs its pumping and self-leveling behavior. Viscosity is also vital for cosmetics design as it influences the flow and feel of products.

Viscosity is integral to the design of lubricants for many industries such as the automotive industry. Engine oils and lubricants must be able to function properly over a wide range of temperatures, from sub-zero conditions in winter to the hot summer months to ensure optimal performance in automobiles.

Proper knowledge of how temperature influences the viscosity of gases and liquids is essential for ensuring the optimal design of commercial and industrial products, from petroleum and refined industrial chemicals to a multitude of domestic consumer goods.

In Summary

Temperature influences the viscosity of liquids and gases, which is a key parameter in the design of many products such as oils, lubricants, food, and cosmetics. Increasing molecular interchange decreases the viscosity of a fluid as temperature increases and vice versa as temperature decreases.

To ensure the optimal design of liquid and gaseous products with the highest performance possible over a range of temperatures, it is essential to understand the influence of temperature on this key material parameter.

More from AZoM: Assessing the Cooked Viscosity of Ground Materials

This information has been sourced, reviewed and adapted from materials provided by Fungilab.

For more information on this source, please visit Fungilab.


  1. Ajit Rai Ajit Rai India says:

    Is there an exception or any cases where the viscosity of gases reduces as the temperature increases?

    • Behrooz Nabavi Behrooz Nabavi Iran says:

      if  the temperature of gas exceeds  the ionization temperature, the viscosity will be reduced. for example >10000 K for Ar.

  2. Anironi Mitra Anironi Mitra United States says:

    how does viscosity of liquids vary with pressure

    • Saurabh Thakur Saurabh Thakur United States says:

      Except water the viscosity of liquid incrases with increase in pressure

  3. Saurabh Thakur Saurabh Thakur United States says:

    Viscosity is proportional to square root then how viscosity increases because value in square root increases then whole value decrases

  4. Nikita Suponya Nikita Suponya United States says:

    Can someone please explain why the viscosity of gases increases with increasing temperature (opposite behavior of fluids).  Is this because the cohesive forces of gases are not as prevalent as that of fluids, and therefore the molecular interchange forces dominate viscous adhesion?  As in, the increased kinetic energy of gas molecules promotes the interaction and adhesion of valence electrons with neighboring molecule nuclei... which causes the increases in shear stress.

  5. Sanoj Kaushik Sanoj Kaushik India says:

    If a liquid has the viscosity of about 6000 cP at 22 degree celsius. So, what will be the viscosity of the same liquid at 40 degree celsius? is there any formula or relation for the same?

  6. rahul kikani rahul kikani India says:

    is there any solution or composition which is become adhesive after applying heating. Also remain dry at room temperature

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Your comment type