# Thermal expansion Definition and 28 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. ### B The collision of molecules during thermal expansion

Greetings everyone. I learned that the distance between molecules in liquid increases while the temperature increases. Hence, its density is decreased. The process is thermal expansion. At the same time, the collision between molecules would be more frequent when the temperature increases...
2. ### I Thermodynamic constant -- misunderstanding

I was reading about thermodynamics in my textbook wheni came across the following thermodynamics constants: However, i don't understand why did we define 1/V inthe constants. What is the point in doing this?
3. ### Thermal Expansion of a Liquid

##\Delta V = \beta V \Delta T## ##\rho _2 = \frac m {V + \Delta V} = \frac { \rho V} {V(1+\beta \Delta T)} = \frac \rho {1+\beta \Delta T}## ##\Delta \rho = \rho _2 - \rho = \frac \rho {1+\beta \Delta T} - \rho = \rho (\frac 1 {1+\beta \Delta T} - 1) = \rho \frac {-\beta \Delta T} {1+\beta...

22. ### Problem: using thermal expansion to calculate sea level rise

Homework Statement Since the 1980's a total of 20 x 10^22 J of additional energy has been absorbed by the worlds oceans. This is 90% of the additional heat our planet is storing as a consequence of global warming. The surface area of the worlds oceans is 361,900,000 km^2 and we will assume this...
23. ### How to solve for the spillover for a spherical container?o

Homework Statement A spherical brass shell has an interior volume of 1.60 x 10-3m^3. Within this interior volume is a solid steel ball that has a volume of 0.70 x 10-3m^3. The space between the steel ball and the inner surface of the brass shell is filled completely with mercury. A small hole...
24. ### Tension (and Frequency) with Change in Temperature

At one point I had been trying to construct an equation which would calculate the tension on a tuned string with a change in temperature (and therefore the fundamental frequency), but found my calculations were wrong. By extension, the purpose of the project was to be able to calculate what...
25. ### Gimbal Joint analysis (Thermal expansion)

Good day, I am currently developing a thermal expansion analysis of a pipe line, I need to validate if the current installed Gimbal joints will withstand those conditions. These gimbal joints just allow angular movement. Is there any software or method that can help me as reference for this...
26. ### Thermal Expansion of piano wire

I'd like to setup an Excel spreadsheet to demonstrate the expected change in string frequency due to small changes in temperature. How should I go about doing this? This is the data from the piano that I can gather: -string length -string diameter -string area -string/partial frequency How do...
27. ### Designing with Thermal expansion in mind

Hi, I am trying to design a tubular probe that's made of stainless steel (304), from what I've read it has a Thermal expansion coefficient of around 9.6 x10^-6 in/in/F give or take on the quality. I want to fill this tube halfway with an Epoxy, however from what I've read this epoxy has a...
28. ### Thermal expansion: the amount of material expanding is "irrelevant"?

Hello everyone! First time asking a question here, go easy on me! I am a first year Mech-Eng student in Ireland, and I need some guidance from one of the amazing brains here at physicsforums. I am told by my thermofluids lecturer that in thermal expansion, the amount of material expanding is...