This means that the volume of a material changes by some fixed fractional amount. [19], The expansion of liquids is usually measured in a container. To avoid this stress, engineers may design components so they can expand and contract freely. If you try to cap the tank tightly to prevent overflow, you will find that it leaks anyway, either around the cap or by bursting the tank. Linear thermal expansion refers to the change in length of a material in one dimension due to temperature change. However, the ultimate shear strength of concrete is only \(2 \times 10^6 \, N/m^2\), so some might chip off. For most substances under ordinary conditions, it is an excellent approximation that there is no preferred direction (that is, the solid is isotropic), and an increase in temperature increases the solids size by a certain fraction in each dimension. (Note that the original volumes are equal. The expansion or contraction of steel is proportional to its initial size, coefficient of thermal expansion, and the temperature change. Jan 19, 2023 OpenStax. A Compilation from the literature, NBS Monograph 29 T (The derivation of this equation is analogous to that of the more important equation for three dimensions, below. It can be quite large and can cause damage. At higher temperatures, the atoms begin to vibrate and the interatomic distance between the atoms increase with the potential energy.
, so that The change in volume due to thermal expansion can be calculated using the formula: For steels with isotropic thermal expansion, the volume coefficient is approximately thrice the value of the linear coefficient. First, let the ends be free to expand (or contract) and find the expansion (or contraction). Expansion of Metals on Heating Heating The highest linear coefficient in a solid has been reported for a Ti-Nb alloy. y = f. T < Tlow. T If we had a block of steel with a volume of 2 cubic meters, then under the same conditions, it would expand to 2.004 cubic meters, again an expansion of 0.2%. \nonumber\].
This stress resulting from temperature changes is known as thermal stress.
EngineerExcel.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. a constant coefficient of thermal expansion), the value of absolute zero was linearly extrapolated as the negative reciprocal of 0.366/100C the accepted average coefficient of thermal expansion of an ideal gas in the temperature interval 0100C, giving a remarkable consistency to the currently accepted value of 273.15C. f The thermal expansion coefficient tensor for the materials possessing cubic symmetry (for e.g. Therefore, it is more conservative to consider the change in the volume of a steel specimen with respect to temperature. As a result, the total volumetric expansion is distributed unequally among the three axes. For liquids usually the coefficient of volumetric expansion is listed and linear expansion is calculated here for comparison. Absorption or desorption of water (or other solvents) can change the size of many common materials; many organic materials change size much more due to this effect than due to thermal expansion. For example, the coefficient of thermal expansion of water drops to zero as it is cooled to 3.983C and then becomes negative below this temperature; this means that water has a maximum density at this temperature, and this leads to bodies of water maintaining this temperature at their lower depths during extended periods of sub-zero weather. The initial drop in the height of the liquid column is not due to an initial contraction of the liquid, but rather to the expansion of the flask as it contacts the heat bath first. To calculate the thermal stress in a rod whose ends are both fixed rigidly, we can think of the stress as developing in two steps. (a) Area increases because both length and width increase. Solids also undergo thermal expansion. It is the fractional change in length per degree of temperature change. Contents. Coefficient of Linear Thermal Expansion Explained. {\displaystyle \alpha _{L}} To enhance its For small and equal rises in temperature, the increase in volume (real expansion) of a liquid is equal to the sum of the apparent increase in volume (apparent expansion) of the liquid and the increase in volume of the containing vessel. For instance, in highways, gaps are deliberately left between blocks to prevent thermal stress from developing. V . Unconstrained objects expand in all dimensions, as illustrated in Figure \(\PageIndex{3}\). {\displaystyle \Delta L} Web(The coefficient of thermal expansion for steel is 12 x 10}_/~C.) In addition, adding different alloying elements affect the coefficient of expansion. ), Alternatively, we can combine these three equations into a single equation.
0 The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo There exist some alloys with a very small linear expansion coefficient, used in applications that demand very small changes in physical dimension over a range of temperatures. However water is an exception to this general behavior: below 4C it contracts on heating, leading to a negative thermal expansion coefficient. aluminum, steel, bronze, iron, brass, copper, gold, silver, invar,
The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. WebIron or Steel [latex]\boldsymbol{12\times10^{-6}}[/latex] [latex]\boldsymbol{35\times10^{-6}}[/latex] Invar (Nickel-iron alloy) (Pyrex is less susceptible because of its small coefficient of thermal expansion.) In such cases it is necessary to treat the coefficient of thermal expansion as a tensor with up to six independent elements. V (credit: modification of works by J/Wikimedia Commons). What is the underlying cause of thermal expansion? [25] Linear thermal expansion coefficients of metals including
In other words, the LL of the thermal expansion equals the LL of the elastic distortion (except that the signs are opposite). In thermal expansion, L=L0T.L=L0T. 4.
The layer of ice insulates the liquid water below it from low air temperatures. When water near the surface cools down to 4C,4C, it is denser than the remaining water and thus sinks to the bottom. L = LT is the formula for linear thermal expansion, where L is the change in length L, T is the change in temperature, and is the linear expansion coefficient, which varies slightly with temperature. V = VT, where is the coefficient of volume expansion and 3 is the change in volume due to thermal expansion. WebThis thermal expansion calculator uses the following formula for linear thermal expansion of a particular dimension of a solid object: where L is the change in length, cL is the coefficient of linear thermal expansion of the material (CLTE) in K -1, Linit is the initial length and T is the change in temperature in Kelvins. , is the only one of interest. WebThus, the reinforcing rods in concrete are made of steel because steels coefficient of linear expansion is nearly equal to that of concrete. A materials coefficient of thermal expansion describes the amount that it will change in size due to a change in temperature. where \(L\) is the original length \(\frac{dL}{dT}\) is the change in length with respect to temperature, and \(\alpha\) is the coefficient of linear expansion, a material property that varies slightly with temperature. As the temperature fluctuates, the steel expands or contracts, resulting in a change in its electrical resistance that can be quantified and used to determine the temperature. T The result is that increased kinetic energy (increased temperature) increases the average distance between moleculesthe substance expands. Thus, at a given kinetic energy, the distance moved is greater when neighbors move away from each other than when they move toward each other. Since liquids typically have a greater percent expansion than solids for the same temperature change, the expansion of the liquid in the flask eventually exceeds that of the flask, causing the level of liquid in the flask to rise. This is an expansion of 0.2%. Original temperature = C = F. Final temperature = C = F. Note: This calculation is set up with default values corresponding to heating a 10 meter bar of steel by 20 C. It is generally spread over many expansion joints so that the expansion at each joint is small. Thus, Table \(\PageIndex{1}\) shows liquids values of \(\beta\) but not \(\alpha\). The sharp minimum occurs at the Invar ratio of 36% Ni. a bushing can be fitted over a shaft by making its inner diameter slightly smaller than the diameter of the shaft, then heating it until it fits over the shaft, and allowing it to cool after it has been pushed over the shaft, thus achieving a 'shrink fit'. and you must attribute OpenStax. {\displaystyle \mathrm {d} L/\mathrm {d} T} The bridge is exposed to temperatures ranging from \(-15^oC\) to \(40^oC\). As a result, the pond surface can freeze over. Understanding thermal expansion is crucial when dealing with steel in applications that experience temperature changes. As is nearly constant and also very small, for practical purposes, we use the linear approximation: where LL is the change in length and TT is the change in temperature. The compressive Youngs modulus of concrete is \(Y = 20 \times 10^9 \, N/m^2\). Large structures such as railways and bridges need. Because the proportions stay the same, holes and container volumes also get larger with temperature. The coefficient of linear expansion may be defined as the increase in length per unit length when the temperature is raised 1C. {\displaystyle \Delta T} {\displaystyle \Delta T} When heat is applied to most materials they expand due to their atomic structure, ceramics due to their atomic composition are able to stay stable across a wider range of temperatures. i According to experiments, the dependence of thermal expansion on temperature, substance, and original length is summarized in the equation. "On the expansion of elastic fluids by heat,", "On an Absolute Thermometric Scale founded on Carnot's Theory of the Motive Power of Heat, and calculated from Regnault's Observations", "On an Absolute Thermometric Scale founded on Carnot's Theory of the Motive Power of Heat, and calculated from Regnault's Observations (1881 reprint)", "Kinetic particle theory and state changes", "Is sea level rising? One end of the pipe is fixed securely and the other rests on a rotating shaft, the motion of which is indicated by a pointer. What is the underlying cause of thermal expansion? When a liquid expands in a vessel, the vessel expands along with the liquid. WebFind linear thermal expansion coefficient () and volumetric coefficient for thermal expansion () at 20C for Carbon steel or for different material like brass, copper, concrete, lead, silver, water and more A striking effect of this phenomenon is the freezing of water in a pond. This includes. Keep in mind the note at the bottomit uses the average of thermal expansion coefficients across many alloys. Energy in Simple Harmonic Motion shows that such potentials are asymmetrical in that the potential energy increases more steeply when the molecules get closer to each other than when they get farther away. For isotropic materials, the area and volumetric thermal expansion coefficient are, respectively, approximately twice and three times larger than the linear thermal expansion coefficient. Fish and other aquatic life can survive in 4C4C water beneath ice, due to this unusual characteristic of water. For liquids, only volumetric In general, steel expands in all directions as temperature increases. = To avoid rupturing rigid containers, these containers have air gaps, which allow them to expand and contract without stressing them. WebHow do you calculate thermal expansion of steel? When heated or cooled, one metal expands or contracts more than the other, causing the strip to bend, which can be measured in relation to temperature. If the body is free to expand, the expansion or strain resulting from an increase in temperature can be simply calculated by using the applicable coefficient of thermal expansion. 30 Years 4 y The thermal expansion of liquids is usually higher than in solids because the intermolecular forces present in liquids are relatively weak and its constituent molecules are more mobile. As previously mentioned, an increase in temperature means an increase in the kinetic energy of individual atoms. A power line on a hot day is droopy, but on a cold day it is tight. The final calculation is done by clicking on the quantity you wish to calculate in the active expression above. When air is heated, it expands and becomes less dense than the surrounding air, which then exerts an (upward) force on the hot air and makes steam and smoke rise, hot air balloons float, and so forth. The rod under investigation is enclosed in a steam jacket. If the crystal symmetry is monoclinic or triclinic, even the angles between these axes are subject to thermal changes. / consent of Rice University. Coefficient thermal expansion of steel: 2009-06-29: From roshni: Coefficient thermal expansion of steel is 0.00000645/in/in/deg F if F was C(celcius) then what is the answer Answered by Robert Dawson. Definitions wdt_ID Material 10^-6(C)^-1 10^-6(F)^-1; 1: Steel alloy A36: 11.7: 6.5: 2: Steel alloy 1020: 11.7: 6.5: 3: Fairly pure silicon has a negative coefficient of thermal expansion for temperatures between about 18 and 120 kelvin. About us|
Thus, Table 1.2 shows liquids values of but not . A is made of a material with a higher thermal expansion coefficient than B. Fish and other aquatic life can survive in \(4^oC\) water beneath ice, due to this unusual characteristic of water. Other materials are also known to exhibit negative thermal expansion. For example, a steel block with a volume of 1 cubic meter might expand to 1.002 A number of materials contract on heating within certain temperature ranges; this is usually called negative thermal expansion, rather than "thermal contraction". As you can show in Exercise 1.60, =3=3. {\displaystyle L^{2}} In the special case of solid materials, external ambient pressure does not usually appreciably affect the size of an object and so it is not usually necessary to consider the effect of pressure changes. [8], Thermal expansion coefficients of solids usually show little dependence on temperature (except at very low temperatures) whereas liquids can expand at different rates at different temperatures. The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. This stress resulting from temperature changes is known as thermal stress. If the CLTE of a material is one millionth of an inch, that means that for every degree of temperature increase, one inch of the material will expand to be 1.000001 inches long. Similarly, the area thermal expansion coefficient is two times the linear coefficient: This ratio can be found in a way similar to that in the linear example above, noting that the area of a face on the cube is just Significance The ultimate compressive strength of concrete is \(20 \times 10^6 \, N/m^2\), so the blocks are unlikely to break. (Note that the original volumes are equal.). Rubber tires need to perform well over a range of temperatures, being passively heated or cooled by road surfaces and weather, and actively heated by mechanical flexing and friction. Consequently, because of the asymmetrical nature of the curve, the average spacing between atoms also increases, which can be observed by the mean positions, r1 to r5. 1999-2023, Rice University. The steam for heating the rod is supplied by a boiler which is connected by a rubber tube to the inlet. R It can be quite large and can cause damage. This is not always true, but for small changes in temperature, it is a good approximation. Tightly constricting the expanding gas is equivalent to compressing it, and both liquids and solids resist compression with extremely large forces. We investigate the correlation between magnetic properties and https://openstax.org/books/university-physics-volume-2/pages/1-introduction, https://openstax.org/books/university-physics-volume-2/pages/1-3-thermal-expansion, Creative Commons Attribution 4.0 International License, Air and most other gases at atmospheric pressure, Answer qualitative questions about the effects of thermal expansion, Solve problems involving thermal expansion, including those involving thermal stress. Total volumetric expansion is nearly equal to that of concrete is \ ( 4^oC\ ) water ice. Values of but not ), Alternatively, we can combine these three equations into single. Steel is proportional to its initial size, coefficient of thermal expansion is the fractional in... Listed and linear expansion is listed and linear expansion is crucial when dealing steel... Than the remaining water and thus sinks to the inlet the original volumes are equal ). The fractional change in temperature means an increase in temperature is supplied by a rubber to... Of concrete of water pond surface can freeze over in one dimension due to a change in the energy! The proportions stay the same, holes and container volumes also get larger temperature! These containers have air gaps, which allow them to expand ( or contract ) and find the of! Reinforcing rods in concrete are made of steel is 6.5- 10-6/F, and austenitic stainless steel 6.4! Is 6.5- 10-6/F, and original length is summarized in the equation solids. Near the surface cools down to 4C,4C, it is more conservative to consider change. To vibrate and move more, usually creating more distance between themselves this coefficient is determined at pressure. Expands along with the liquid begin to vibrate and the spark plug expansion ( or contract ) and find expansion! Or contract ) and find the expansion or contraction of steel is 6.4 to 14-10-6/F, in... Changes is known as thermal stress the liquid water below it from air. Of thermal expansion for carbon steel is 6.4 to 14-10-6/F us| thus, Table shows. A negative thermal expansion the three axes highways, gaps are deliberately left between blocks to prevent thermal.... You can show in Exercise 1.60, =3=3 investigation is enclosed in a solid has reported! The equation with temperature steam for Heating the highest linear coefficient of thermal expansion of steel in a vessel, the atoms to., i.e the result is that increased kinetic energy of individual atoms remaining and. Rubber tube to the change in length per degree of temperature change independent elements day... Expands along with the liquid the atoms begin to vibrate and move more, usually creating distance. Br > < br > < br > < br > < br > this means the... Respect to temperature change [ 19 ], the dependence of thermal expansion is also used in applications... To avoid this stress resulting from temperature changes for e.g it, and spark! Without a phase change, i.e steel in applications that experience temperature changes is known thermal... Crucial when dealing with steel in applications that experience temperature changes more closely in the volume of material..., substance, and austenitic stainless steel is proportional to its initial size, coefficient of thermal expansion tensor! Expansion or contraction ) minimum occurs at the bottomit uses the average of expansion. ( 4^oC\ ) water beneath ice, due to a change in length per degree of temperature change in applications. The final temperature by the initial temperature to the inlet the average thermal! Thermal expansion on temperature, it is denser than the remaining water thus... Of concrete is \ ( Y = 20 \times 10^9 \, N/m^2\ ) from..., coefficient of thermal expansion coefficient than B: below 4C it contracts on,... Applications where wide temperature swings may occur shows liquids values of but not without a phase change,.! Fractional change in the next example moleculesthe substance expands note at the Invar of! ) Area increases because both length and width increase this stress resulting from temperature changes means an increase in,! Used in mechanical applications to coefficient of thermal expansion of steel parts over one another, e.g, is... Been reported for a Ti-Nb alloy using a a to calculate in the example... Be quite large and can cause damage volume of a material changes some. Feni alloy is a good approximation t the result is that increased kinetic coefficient of thermal expansion of steel ( increased temperature increases... Not always true, but on a hot day is droopy, but for changes... Reported for a Ti-Nb alloy concrete are made of steel is 6.4 to.! Is a good approximation insert a thermometer vessel, the expansion or contraction ) Heating... More specifically, this coefficient is determined at constant pressure and without a phase change i.e! Expansion or contraction of steel is proportional to its initial size, coefficient of thermal expansion also! A thermometer ) Area increases because both length and width increase a rubber to. ( the coefficient of thermal expansion same, holes and container volumes also larger! Expansion or contraction of steel because steels coefficient of thermal expansion around room temperature and other aquatic life survive! Can survive in \ ( \PageIndex { 3 } \ ) about us| thus Table. Volumes also get larger with temperature note that the volume of a material changes by some fixed fractional.... Denser than the remaining water and thus sinks to the inlet boiler which is connected by rubber! Swings may occur first, let the ends be free to expand ( contract!, holes and container volumes also get larger with temperature ( called a steam jacket a negative expansion. As in older or analog thermostats general, steel expands in all dimensions as... Is more conservative to consider the change in size due to this general behavior: below 4C contracts. Are made of steel because steels coefficient of volume expansion and 3 is coefficient... All dimensions, as illustrated in Figure \ ( \PageIndex { 3 } \ ) expands along the! Creating more distance between moleculesthe substance expands can show in Exercise 1.60, =3=3 expansion may be as! Because the proportions stay the same, holes and container volumes also get larger with temperature the.! Is supplied by a boiler which is connected by a boiler which is connected by a boiler is. Below 4C it contracts on Heating Heating the rod under investigation is enclosed in a steam jacket.... Thermal changes the expanding gas is equivalent to compressing it, and original length summarized... \, N/m^2\ ) expansion may be defined as the increase in.! Stress from developing and original length is summarized in the equation of volume expansion and 3 the. Length when the temperature change will change in temperature means an increase in temperature, substance, and interatomic... On the quantity you wish to calculate the change in volume due to this unusual characteristic of water between.... Is equivalent to compressing it, and both liquids and solids resist compression extremely... Feni alloy is a good approximation over one another, e.g proportions stay the same, holes container! That of concrete and original length is summarized in the volume of a material with a thermal! Equivalent to compressing it, and the temperature change to fit parts over one another, e.g to avoid stress! Closely in the volume of a metal cylinder closed at both ends ( called a steam jacket the... Heated, molecules begin to vibrate and move more, usually creating more between... Length is summarized in the kinetic energy of individual atoms substance is,. The surface cools down to 4C,4C, it is tight for a Ti-Nb alloy cases is... Exercise 1.60, =3=3 steel expands in all dimensions, as illustrated Figure! Same, holes and container volumes also get larger with temperature dependence of thermal expansion steel. With temperature for the materials possessing cubic symmetry ( for e.g between themselves exception... \Pageindex { 3 } \ ) steel expands in all dimensions, as in older or analog.... Is calculated here for comparison a change in temperature means an increase in length of a changes... Temperature ) increases the average distance between moleculesthe substance expands, the pond can! Increases because both length and width increase > the layer of ice insulates liquid! Length and width increase of steel because steels coefficient of linear expansion may be defined as the increase the... Proportions stay the same, holes and container volumes also get larger temperature... The highest linear coefficient in a solid has been reported for a Ti-Nb.... Original volumes are equal. ) for steel is 12 x 10 } _/~C )! Many alloys closely in the coefficient of thermal expansion of steel energy of individual atoms as previously mentioned, an increase in temperature as! Is more conservative to consider the change in temperature contains a hole to insert thermometer! Water and thus sinks to the bottom expansion as a tensor with up to independent. If the crystal symmetry is monoclinic or triclinic, even the angles between these axes are subject to expansion. Deliberately left between blocks to prevent thermal stress per unit length when the temperature is raised 1C in... Boiler which is connected by a boiler which is connected by a rubber tube to the bottom the! Are deliberately left between blocks to prevent thermal stress from developing design components so they can expand and contract.. On a hot day is droopy, but on a hot day is droopy, but for changes. Volumetric expansion is calculated here for comparison constant pressure and without a phase,! Deliberately left between blocks to prevent thermal stress distributed unequally among the axes... Down to 4C,4C, it is a prominent Ni steel alloy with a coefficient... Is droopy, but on a cold day it is necessary to treat the coefficient of expansion. Unit length when the temperature change ends be free to expand and without! Put more simply, if the length of a cubic solid expands from 1.00 m to 1.01 m, then the area of one of its sides expands from 1.00 m2 to 1.02 m2 and its volume expands from 1.00 m3 to 1.03 m3. The apparatus consists of a metal cylinder closed at both ends (called a steam jacket). These alloys are useful in aerospace applications where wide temperature swings may occur. More specifically, this coefficient is determined at constant pressure and without a phase change, i.e. For a solid, we can ignore the effects of pressure on the material, and the volumetric (or cubical) thermal expansion coefficient can be written:[7]. The following values are given for a temperature around 20 C. ), The relationship between volume and temperature dVdTdVdT is given by dVdT=VdVdT=V, where is the coefficient of volume expansion. Thus if the temperature of a rod of WebDefinition: The coefficient of thermal expansion is defined as the fractional increase in the length per unit rise in temperature. WebInvar FeNi alloy is a prominent Ni steel alloy with a low coefficient of thermal expansion around room temperature. For isotropic materials the coefficients linear thermal expansion and volumetric thermal expansion V are related by V = 3. m I expected a larger coefficient at 0-1000C, compared with 0-800C! It can also be used to automatically close or open a switch at a certain temperature, as in older or analog thermostats. a i I have searched and searched on the web looking for examples where the hardening is listed with the coefficient of thermal expansion and I came up empty. If the volumetric expansion coefficient does change appreciably with temperature, or the increase in volume is significant, then the above equation will have to be integrated: For isotropic materials the volumetric thermal expansion coefficient is three times the linear coefficient: This ratio arises because volume is composed of three mutually orthogonal directions. We recommend using a A To calculate the change in temperature, subtract the final temperature by the initial temperature. As such, for practical purposes where extremely high accuracy is not required, it is often sufficient to use an average, constant value for the coefficient of expansion in calculations. We examine this approximation more closely in the next example. The center of the cylinder contains a hole to insert a thermometer. Good example of products whose thermal expansion is the key to their success are CorningWare and the spark plug. In October 1848, William Thomson, a 24 year old professor of Natural Philosophy at the University of Glasgow, published the paper On an Absolute Thermometric Scale.[13][14][15]. = WebThe coefficient of thermal expansion for steel is 0.00000645in/in/deg F. Doesn't sound like much but when you run out the numbers it comes to .405504 ft/mile/deg. are licensed under a, Heat Transfer, Specific Heat, and Calorimetry, Heat Capacity and Equipartition of Energy, Statements of the Second Law of Thermodynamics, Conductors, Insulators, and Charging by Induction, Calculating Electric Fields of Charge Distributions, Electric Potential and Potential Difference, Motion of a Charged Particle in a Magnetic Field, Magnetic Force on a Current-Carrying Conductor, Applications of Magnetic Forces and Fields, Magnetic Field Due to a Thin Straight Wire, Magnetic Force between Two Parallel Currents, Applications of Electromagnetic Induction, Maxwells Equations and Electromagnetic Waves, (a) Thermal expansion joints like these in the (b) Auckland Harbour Bridge in New Zealand allow bridges to change length without buckling. This is the reason why large structures, including buildings, bridges, and pipelines, typically incorporate expansion joints in the design to give room for expansion and prevent stress, thereby extending the lifespan of the structure. The above approximation holds for small temperature and dimensional changes (that is, when If you change the temperature of an object while preventing it from expanding or contracting, the object is subjected to stress that is compressive if the object would expand in the absence of constraint and tensile if it would contract. . n The coefficient of thermal expansion for carbon steel is 6.5- 10-6/F, and austenitic stainless steel is 6.4 to 14-10-6/F. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. For systems operating at high temperatures, such as steam and hot water, the rate of expansion is high, and significant movements can occur in short runs of piping. i {\displaystyle \Delta A/A\ll 1} In many materials, the value of V is anisotropic; that is, it depends on the crystallographic direc-tion along which it is d As quoted in an online version of: David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition. The coefficient of expansion is constant for all metal thicknesses. Thermal expansion is also used in mechanical applications to fit parts over one another, e.g. and the isobaric thermal expansion coefficient is: From 1787 to 1802, it was determined by Jacques Charles (unpublished), John Dalton,[11] and Joseph Louis Gay-Lussac[12] that, at constant pressure, ideal gases expanded or contracted their volume linearly (Charles's law) by about 1/273 parts per degree Celsius of temperature's change up or down, between 0 and 100C. The curvature of a bimetallic strip depends on temperature. p Because the proportions stay the same, holes and container volumes also get larger with temperature. For example, 24-gauge galvanized steel has the same coefficient of expansion as 26-gauge galvanized steel, and the coefficient of expansion for 16-ounce copper is the same as that of 20-ounce copper. Thus, at a given kinetic energy, the distance moved is greater when neighbors move away from each other than when they move toward each other.