What is Thermal expansion: Definition and 276 Discussions

Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). 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. As energy in particles increases, they start moving faster and faster weakening the intermolecular forces between them, therefore expanding the substance.

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  1. fluidistic

    Thermal expansion of a pendulum

    Hi, I've done the problem but I'm unsure of my answer. I would be glad if you could check it out. Homework Statement A steal pendulum is considered a clock at a certain temperature. What is the maximum variation of temperature we can submit to the pendulum if it cannot delay more than one...
  2. P

    How to Calculate Volume Thermal Expansion Coefficient?

    Homework Statement Prove that the volume thermal expansion coefficent of a solid is equal to the sum of its linear expansion coefficients in the three directions: B = Ax + Ay + Az Homework Equations B = (dV/V)/dT A = (dL/L)/dT The Attempt at a Solution My thought was using dV/V...
  3. M

    Problem with Thermal expansion: volume

    Homework Statement The temperature of a block of lead is raised from 0°C to 100°C. What is the percentage change in its density? (The density of lead at 0°C is 11,300 kg/m3.) Homework Equations ΔV = Vi βΔT The Attempt at a Solution it gave the wrong answer when i tried to use the...
  4. O

    Thermal Expansion of Solvent Mixture question

    Hello, Currently, I am working on a science project involving the creation of silica aerogels through the process of freeze-drying. As a result, i need to experiment with mixtures of solvents with low thermal expansion coefficients (so the crystallization of the solvents will not damage the...
  5. M

    Quick question on thermal expansion.

    Homework Statement In a bimetallic strip of brass and copper which curls when heated, the brass is on the inside of the curve. True or false? Homework Equations deltaL=alpha*Lo*deltaT The Attempt at a Solution It is false but I do not get why. Brass has a higher coefficient...
  6. B

    How Does Temperature Affect the Diameter of a Hole in an Aluminum Plate?

    Homework Statement A hole in an aluminum plate has a diameter of 1.179 cm at 22.00 degrees Celsius. Part A asks for the diameter of the hole at 199 degrees Celsius.? Part B asks for the temperature of the hole when its diameter is 1.177 cm? Homework Equations ∆L = alpha L(0) ∆T...
  7. B

    Thermal Expansion of a steel plate

    Homework Statement A steel plate has a circular hole with a diameter of 1.000 cm. In order to drop a Pyrex glass marble 1.003 cm in diameter through the hole in the plate, how much must the temperature of the system be raised? (Assume the plate and the marble always have the same temperature)...
  8. B

    Searching for Joule Thomson and Thermal Expansion Coefficients of Methane

    I've been scouring the web in search of a Joule Thomson coefficient value for methane, but so far no luck. I have the volume, temperature, and specific heat as well... so I could also use the coefficient of thermal expansion for methane.. but I can't find that anywhere either! Does anyone...
  9. P

    Thermal Expansion of Mercury and Water

    Homework Statement When the temperature of liquid mecury increases by one degree celsuis , its volume increases by one part in 5500. The fractional increase in colume per unit change in temperature(when the pressure is held fixed ) is called the thermal expanision coefficient , \beta...
  10. I

    Calculating Coefficient of Thermal Expansion for a Rod

    A rod is measured to be exactly 21.81 cm long using a steel ruler at a temperature of 21.5°C. Both the rod and the ruler are placed in an oven with a temperature of 345.0 °C where the rod now measures 21.93 cm using the same ruler. What is the coefficient of thermal expansion for the material of...
  11. S

    Thermal expansion in heat engine

    A brass piston of diameter 25 cm at 20 degrees C must be able to function at 150 degrees C. In order to do so it must fit inside a steel cylidrical chamber. What must the minimum initial diameter of the cylinder be so that the piston never rubs against it. alpha=2x10^-5 for brass...
  12. C

    Thermal expansion, percent change in density problem

    Homework Statement When the temperature of a metal cylinder is raised from 0.0°C to 100°C, its length increases by 0.23%. Find the percent change in density. Homework Equations ∆L = L∆T p=m/v The Attempt at a Solution I don't have any real idea how to start the problem. How...
  13. A

    Thermal Expansion with rod and ruler.

    Homework Statement A rod is measured to be exactly 21.02 cm long using a steel ruler at a temperature of 21.1oC. Both the rod and the ruler are placed in an oven with a temperature of 340.0oC where the rod now measures 21.32 cm using the same ruler. What is the coefficient of thermal...
  14. R

    Thermal Expansion for an Ideal Gas

    Homework Statement The pressure p , volume V, number of moles n, and Kelvin temperature K of an ideal gas are related by the equation pv=nRT , where R is a constant. Prove that the coefficient of volume expansion for an ideal gas is equal to the reciprocal of the Kelvin temperature if the...
  15. T

    Thermal Expansion of a gold ring

    Homework Statement You somehow manage to get a gold ring with inner diameter 2.26 cm stuck on your finger, even though your knuckle has a diameter of 2.3 cm. The temperature of the ring is 23 degrees C. To what temperature would you have to heat the ring in order to get it off your finger...
  16. M

    How to calculate deflection for thermal expansion of a ring?

    Hopefully quick/easy question. I am modeling essentially a flat plate under pressure load in ANSYS with a large thermal change. With fixed or simple support at the outer edges, of course the thermal stresses are crazy high. To try and get a better estimate of stresses without modeling the...
  17. S

    Thermal Expansion: Solve Problem w/Turpentine & Al Cylinder

    Homework Statement A hollow aluminum cylinder 18.0 cm deep has an internal capacity of 2.000 L at 24.0°C. It is completely filled with turpentine and then slowly warmed to 88.0°C. Note: If applicable, Table 19.1 is available for use in solving this problem. The Attempt at a Solution I solved...
  18. D

    Thermal expansion problem

    Hey, let's say I have a pipe with a fastener screwed into it. If they are of different materials, how can I find out the pressure/gap between the bolt and nut if they are heated? I don't expect a complete solution of course, just a couple of hints to get me going :) Thanks!
  19. P

    Calculate a thermal expansion pitch change

    Can anyone please help me figure out how to calculate the change in pitch [in cents] for a piano wire with a given change in temperature? I am not really sure where to start. I assume that I will need to first figure out the thermal expansion of the wire, but how do I then take that...
  20. 0

    Thermal Expansion of a brass plug

    Homework Statement A brass plug is to be placed in a ring made of iron. At 20 C the diameter of the plug is 8.753 cm and that of the inside ring is 8.743 cm. They must both be brought to what common temperature in order to fit? What if the plug were iron and the ring brass? Homework...
  21. B

    Does Using Celsius Instead of Kelvin Affect Thermal Expansion Calculations?

    Homework Statement Usually when temperatures are written as "T", they are given in kelvins and when written in "t" they are given in celsius. The equation dL = aLdT used T for temperature yet, in the experiment temperature is measured as celsius. Is there any difference? Why? Homework...
  22. T

    How does thermal expansion effect the diameter of a hole?

    How does thermal expansion effect the diameter of a hole in a sheet metall, When we r dealing with length it is quite easy since then it is only the propotion of change in lengt, and there r standard formulas for this ... But how do you do for a hole in a sheet metal who are free to...
  23. R

    What are the coefficients of thermal expansion for methanol in F^-1?

    Does anyone have coefficients of thermal expansion in F^-1 instead of in C^-1. I have worked out an equation from thermodynamic first principals that derives the throttling equation I then did the first order non-seperable differential equation: dT/dP = C1*T - C2 to get the following...
  24. M

    Thermal Expansion of Rod Problem

    Homework Statement In a certain experiment, it is necessary to be able to move a small radioactive source at selected, extremely slow speeds. This is accomplished by fastening the source to one end of an aluminum rod and heating the central section of the rod in a controlled way. If the...
  25. S

    Thermal Expansion: Hole Diameter in Heated Steel

    Homework Statement this is a 2 marks question a hole is drilled through a piece of steel what happens to the diameter of the hole as the steel is heated Homework Equations The Attempt at a Solution i guess the diameter of the hole decreases as both the outer as well as inner...
  26. H

    Thermal expansion and coefficient of linear expansion

    at 20C a rod is exactly 20.05cm long on a steel ruler. Both the rod and the ruler are placed in an oven at 270C, where the rod now measures 20.11cm on the same ruler. What is the coefficient of linear expansion for the material of which the rod is made? Homework Equations...
  27. C

    Solve Thermal Expansion: Floating Glass Block in Methyl Alcohol

    Homework Statement A hollow glass block is floating in a container of methyl alcohol. Initially, everything is at a temperature of 20 degrees C, and just 7% of the block is above the suface of the alcohol. If you heat the container (gently and evenly- so that everything warms up together)...
  28. F

    Thermal Expansion Ethanol Problem

    Homework Statement You pour 108 cm^3 of ethanol, at a temperature of -10.0 degrees C, into a graduated cylinder initially at 20.0 degrees C, filling it to the very top. The cylinder is made of glass with a specific heat of 840 J/(kg *K) and a coefficient of volume expansion of 1.2 *10^-5 K^-1...
  29. G

    Thermal Expansion of Metal Ball Problem

    [SOLVED] Thermal Expansion Problem Homework Statement A metal ball is just able to pass through a metal ring. When the ball is heated thermal expansion will not allow it to pass through the ring. What would happen if the ring rather than the ball, were heated? Would the ball pass through...
  30. G

    Thermal expansion coefficient for liquids.

    I am looking for a liquid with a high expansion coefficient. This liquid should act as a working fluid in a energy cycle based on a system where the working fluid does not change phase from liquid to gas. So far I have found pentane as the most suitable liquid - but I would like to know if...
  31. M

    Does Thermal Expansion Affect the Enclosed Volume or the Shell Material Volume?

    [SOLVED] thermal expansion hi everybody my question is: a spherical shell is heated. the volume changes according to the equation V(T)=V(0)(1+yT) where y=volume coeff. of thermal expansion. does this volume refer to the volume enclosed by the shell or the volume of the material making up the...
  32. T

    How Much Force Is Needed to Prevent a Steel I-Beam from Expanding When Heated?

    Homework Statement a)A steel I-beam is 30m long, and its cross-sectional area is .001 square meters. If its temperature is increased by 80C what is its change in length? Ysteel = 20x10^10 N/m^2 (Alpha)steel = 1.2x10^-5/C b) How much force should be applied to keep it from expanding...
  33. R

    Thermal expansion on a spring?

    [b]1. A brass spring has an unstrained length of .18m and a spring constant of 1.3 E4 N/m. THe temperature increases from 21 cel to 135 cel. what is the magnitude of the compressional force that must be applied to the heated spring to bring it back to its original lenght!? [b]2. Linear...
  34. J

    Thermal Expansion on Piping Systems

    Can anyone offer a literature reference regarding thermal expansion of piping systems? I am interested in reading up on how the use of a linear coefficient compares with using an area coefficient when accounting for diameter expansion. Thanks.
  35. B

    What Temperature Allows a Ring to Slide Off a Sphere?

    Problem Sphere has ring around it. At T=70C the diameter of the sphere is 0.05% larger than the diameter of the ring. At what temp will the ring be able to come off sphere? Attempt D_s=1.0005*D_r at 70C Sphere delta_V=beta*V_o*delta_T Ring delta_L=alpha*L_o*delta_T L=pi*D_r...
  36. B

    Thermal Expansion - Conceptual

    Homework Statement For each of the following statements, determine whether is is correct or incorrect. A. An iron plate has a hole cut in its center. When the plate is heated, the hole gets smaller. B. When the Celsius temperature doubles, the Fahrenheit temperature doubles. C...
  37. S

    Thermal Expansion of Gas in a Tank

    Homework Statement An underground gasoline tank at 54°F can hold 1100 gallons of gasoline. If the driver of a tanker truck fills the underground tank on a day when the temperature is 82°F, how many gallons, according to his measure on the truck, can he pour in? Assume that the temperature of...
  38. J

    Thermal Expansion on Pendum- Period related question

    Homework Statement A grandfather clock is calibrated to 20 degrees Celsius. If the room temperature were to be increased to and maintained at 30 degrees, how much would the clock run slower by in a 7 day period? (Yes, the length of the pendulum is NOT given) Can someone help me with this...
  39. I

    Thermal Expansion with bending bars

    Well I'm having problems trying to understand this problem with a bending bar in my textbook. Since we barely touched the subject of thermal expansion in class (there were no examples on this kind of problem) I'm a little confused. The hint in the problem makes no sense to me and gets me no...
  40. J

    What is the Correct Temperature Yesterday?

    While studying for the Fundamentals of Engineering exam, I came across the following problem that has me puzzled: The problem then goes on to give four possible answers (37.06 degrees C, 38.06 degrees C, 39.06 degrees C, and d. 40.06 degrees C) though I'm convinced that none of them can be...
  41. S

    Thermal Expansion and temperature changes

    The problem is listed. I can't figure out thermal expansion really...if there was one material, I know you can say that the displacement due to thermal expansion is equal to the displacement due to the loadings via the wall (that's why normal stresses are developed in that case). But, three...
  42. D

    Thermal Expansion - Find Current for Iron, Aluminium & Copper Coils

    Hi guys, I need to find out what current i need to expand different type of coils. eg iron, aluminium, copper, etc. Is there a website that can give me this information? I tried searching but no luck. Thx Dazza
  43. C

    Volumetric thermal expansion coefficient

    Actually it's a math question. Can I cancel V from both side in step 3? thx!
  44. C

    What is the necessary gap width for thermal expansion of concrete sidewalks?

    Concrete sidewalks are always laid in sections, with gaps between each section. For example, the drawing shows three identical 2.4 m sections, the outer two of which are against immovable walls. The two identical gaps between the sections are provided so that thermal expansion will not create...
  45. B

    What is the Common Temperature for Expansion of a Steel Ring and Aluminum Rod?

    Homework Statement A steel ring with a hole having area of 3.96 cm2 is to be placed on an aluminum rod with cross-sectional area of 4.00 cm2. Both rod and ring are initially at a temperature of 36.0°C. At what common temperature can the steel ring be slipped onto one end of the aluminum rod...
  46. U

    Thermodynamics: Maxwell relation and thermal expansion

    Use a Maxwell relation and the third law of thermodynamics to prove that the thermal expansion coefficient beta must be zero at T=0. I know that B=(delta V/V)/T and I also know the Maxwell relations. I'm just not sure which one to use and how to relate it to beta.
  47. C

    Volume Thermal Expansion Question ?

    Volume Thermal Expansion Question!?? a spherical brass shell has an interior volume of 1.60 x 10^-3 m^3. Within this interior volume is a solid steel ball that has a volume of 0.70 x 10^-3 m^3. The space between the steel ball and the inner surface of the brass shell is filled completely with...
  48. S

    Thermal Expansion of thermometer in ice water

    Here is a two part problem I'm having trouble with: The length of the column of mercury in a thermometer is 4cm when the thermometer is immersed in ice water and 23.5cm when the thermometer is immersed in boiled water. a) What should be the length at room temperature 22degreesCelcius? I...
  49. C

    How Do You Calculate the Coefficient of Expansion for Glass Using Mercury?

    Hey guys, having some trouble on some thermodynamics this time. 1) A glass flask whose volume is V_o at 0.0 degrees C is completely filled with mercury at this temperature. When flask and mercury are warmed to a temperature of T, a volume V of mercury overflow. If the coefficient of volume...
  50. P

    Calculating Temperature Change for Steel Rod Stretching

    a steel rod undergoes a streching force of 500n its crossectional area is 2cm^2 find the temp change that would elongate the rod by same amount i useyoungs modulus to get change in length so ym= (F/A)/(deltaX/h) so i solve for r (which is = to h from area of circle) and with a ym for steel...
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