We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is Thermal Expansion?

By Jason C. Chavis
Updated: May 21, 2024

As a result of changes in temperature, matter changes in volume. This concept is known as thermal expansion. As a substance heats up, the particles within the matter move about, becoming more active as the temperature rises. This activity causes the particles to need additional space between each other, enlarging the size of a material. The equation to describe this concept is known as the coefficient of thermal expansion and can be defined by the fact that the degree of expansion is divided by the change of temperature in a material.

The use of certain solid materials in construction and engineering is a direct result of this thermal expansion. The need for objects to retain their shape without major distortion results in the common practice of using metals and plastics. For example, a hammer needs to retain its shape as temperatures rise to prevent impairment. While this principle is generally true based on the type of material used, certain structures, such as crystals, can posses different coefficients of thermal expansion depending on the shape.

Likewise with the concept of negative thermal expansion, conditions such as extreme cold cause materials to contract for the exact opposite reasons as regular thermal expansion. Often other materials with different coefficients are needed in conjunction with these solids. One example would be a window, which needs rubber fittings to prevent the expansion and contraction of the metal frame.

The harder the material, the lower the thermal expansion. Liquids will expand more readily than solids. This is caused by the fact that as the energy bond between the particles increases, the thermal expansion decreases in these substances. In addition, certain materials change size due to the absorption or desorption of water or solvents.

A type of expansion known as anisotropic expansion can occur within certain types of materials. This means that the solid will not expand exactly alike in each direction. Any material with a number of layers, such as graphite, usually expands more readily in a perpendicular fashion with the layers rather than vertically against the layers. This can be beneficial for designers when attempting to make a fitting that would need to expand in only one direction when exposed to temperature changes.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By keanwei282 — On Nov 05, 2012

What are the changes that will happen in the properties of two different materials with different coefficients of thermal expansion?

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.