What is Materials: Definition and 980 Discussions

A material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified based on their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials and their applications.
Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials by synthesis.
In industry, materials are inputs to manufacturing processes to produce products or more complex materials.

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  1. R

    Why is the speed of light different when traveling in different materials?

    In my physics class, we learned that light moves slower when traveling in different materials like water or air. However, it is the fastest in a vacuum. I was wondering why this happens. I read something about a refraction index in the different materials. For example, water has a refraction...
  2. M

    Can materials act as a low pass filter for laser beams?

    There are materials which block laser beams (or light globally) or weaken its intensity via shading i.e. a beam must have crossed a specific energy barrier in order to pass this shading where beams with less energy will fade and won't pass. The question is, is there a material or a type of...
  3. N

    Choosing materials for a bridge

    Hello everybody, We need your advice with a project for building a simple one-beam bridge. We have figured out the dimensions, required load, max allowable stress and safety factor. We need to choose a material that would support our requirements. Which formula should we use to compare...
  4. P

    Why do compressed materials fail in shear?

    Why when you compress materials like concrete do they fail in shear? Can the thing you're compressing be too small to fail in this way?
  5. V

    To pursue a PhD in NE with materials specialization

    I am an undergraduate student in nuclear engineering, and I want to pursue a PhD in nuclear materials. I have research background in materials corrosion, but my undergraduate university doesn't have courses on materials science for nuclear engineering students. I have noticed that many...
  6. A

    Math Subject GRE Practice Materials

    I am taking the Math Subject GRE on Saturday and finding study materials has been nothing short of a major pain. Maybe we should compile all of the study materials we have found into one central location here. I'll start: http://www.math.ucla.edu/~cmarshak/GREWorkshop.html Feel free to...
  7. T

    Differences between para and ferroelectric materials

    Hi I am having toruble differentiating between the two. below the curie temperature BaTiO3 behaves as a ferroelectric, the Ti ions are offset from the centre, causing a polar domain. But it has a net polarisation is zero. Now above the curie temperature all the dipole cancel each other out...
  8. C

    Bayesian statistics learning materials

    Does anyone here know any good Bayesian statistics, Bayesian hypothesis testing, Bayesian inference, etc. learning materials (preferably online)?
  9. N

    Magnetic Force on Materials

    Homework Statement A) Which of these materials will feel a force from a permanent magnet - wood, aluminum or steel? B) Will the materials that are attracted by the magnet be attracted to the north pole of the magnet, the south pole, or both? Homework Equations The Attempt at a...
  10. V

    Programs Is a Background in Materials Science Essential for a PhD in Nuclear Materials?

    Hi, everyone! I am undergraduate student from China. I am applying to pursue a PhD degree in United States next year. I am interested in nuclear materials, but the problem is that my home school offers little course on materials science. I am affraid that students of materials science may be...
  11. A

    Decrease permeability of ferromagnetic materials

    Hello. I know very few things about solid state physics, so my question is very basic.. I'm just searching for a clue.. Have some of you ever heard about, or imagine a way, of decreasing the permeability of a ferromagnetic material? Not by raising temperature, but with electric field or...
  12. P

    Strength of Materials - Steel Beams

    Homework Statement QUESTION 2 (Total 20 marks) Figure 4 below shows a diagrammatic section of the floor of a typical house suspended over a garage. The steel beam shown in section spans 7.2 metres centre to centre of supports. The floor, including an allowance for the self weight of...
  13. A

    Isomorphous Materials: Beyond Copper-Nickel Diagrams

    I'm working on an assignment about phase diagrams and one of the topics we skim is isomorphous phase diagrams. As a topic its easy to grasp and the copper nickel diagram is a good example, however I was wondering if someone can outline any other isomorphous materials because I would like to use...
  14. R

    Are the Material Properties in My Physics Library Accurate?

    Hi everyone! Im developing an application with a physics library. In the application I pre-setted some materials with the following properties, Density, Friction and Restitution Im not sure if this informations are truly trustable, Can you guys just review this for me...
  15. R

    Reflectivity, emissivity, and absorptivity of opaque materials

    Homework Statement what is the relation between reflectivity, emissivity, and absorptivity for an opaque material? if an opaque material's reflectivity is 0.075 for solar radiation in the visible range and 0.95 for radiation of a heated surface of 80 degrees Celsius in the far infrared...
  16. N

    Materials Science: Close packed vs closest packed

    Sorry if this is the wrong forum, but I figure it is the most relevant since it deal with crystal structures. I'm taking a materials science course currently, and have some confusion on the definition of close packing. Since it seems to represent different things depending on if it is viewed...
  17. S

    Capacitor with two angled dielectric materials

    Homework Statement Find the capacitance of the capacitor shown in the figure. Asume H << L. http://imageshack.us/a/img39/1935/capacitor.png Homework Equations Capacitance of a plate parallel capacitor with a dielectric material e: eA/H where A denotes the area of the plate, and H...
  18. R

    High strength high temp rated non conductive materials

    Does anyone know of any good materials to make pipe out of that can withstand around 200 psig, 250 F and is completely non conductive? Would also be nice if it was durable to external bumps and drops as well. Was thinking carbon fiber but that won't handle high temperature.
  19. S

    Moment for bending materials test

    Homework Statement I have to do the following practical, but I am unsure of how to calculate one of the variables. We are doing this test and we are given this information to calculate E. I have equations on how to calculate R and I, but I am not sure how to calculate M. It's...
  20. D

    Bremsstrahlung from different materials

    I'm curious about the compatibility of a whipple shield and bremsstrahlung prevention(like that provided by paraffin). Until a short time ago, I was under the impression that bremsstrahlung is only generated when a charged particle collides with a metal. This is apparently not the case. So...
  21. U

    Where Can I Send Samples for Advanced Materials Characterization?

    Dear All, I am looking for contact address(es) of university institution(s) where i could send samples for characterization. I work using XRD, EDX, SEM, IS(impedance spectroscopy analyzers-upto GHz frequencies). Also, DTA/DSC/TGA, UV-Vis and NMR, among others, principally. I Work...
  22. B

    Linear isotropic dielectric mixture two materials

    Homework Statement Consider an x1:x2 mix of two linear isotropic dielectrics (by volume). x1+x2=1. On large length scales the mixture is homogenous and can be characterized with a dielectric constant ε_mix but on short length scales the material is granular so the dielectric constant is...
  23. S

    Learning Materials for Speech, Music, and Acoustics Research

    I am interested in starting to research into the acoustics of speech and music. In particular I want to analyze the spectral profile of human voice in hopes of finding relationships between it and music. A possible future direction for this research is to improve synthetic speech to mimic...
  24. dbmorpher

    Solar Driven low Resource Consuption Steam Engine Materials

    Hi I'm dbmorpher For my local History fair I am basing my report on the Indutrial Evolution and it's Inventions namely the Steam Engine. I wanted to know if there was an easy way to make a steam engine that was or had... Low cost parts No fuel such as coal or wood No need for complicated...
  25. M

    Compressive pressure between interacting materials

    Hello. I'm conducting some experiments to test for the pressure exerted by a thermally expanding cylinder inside a tube. The cylinder is placed snugly inside the tube, usually with zero to a few 0.001s clearance. The cylinder has a higher coefficient of friction than the tube, therefore we...
  26. T

    Recently graduated with BE in Materials Engineering. What should I do next?

    I recently graduated from NUST, Pakistan completing my Bachelors in Materials Engineering. I've applied to several industries within and outside Pakistan but so far the response has been disappointing. I've been confused regarding where to start. There are a couple of questions I want to ask...
  27. P

    Materials - determining indices for planes. can someone check answers?

    Homework Statement I'm not sure if this is the right section, but I also posted in the chemistry section. I'm taking a materials engineering class which involves a lot of chemistry. I attached the problem. Homework Equations The Attempt at a Solution Plane A: since the plane...
  28. X

    Thermal Conductance Through Two Materials

    I had a thermal conductance homework problem where heat flowed through gold, and then silver. Both materials were of the same length and same cross sectional area. The problem mentioned that the energy transfer had reached a steady state, and I found through doing the problem that under these...
  29. M

    Materials Science/Attraction Forces Between Ions

    Homework Statement Calculate the force of attraction between a Ca2+ and an O2- ion, the centers of which are separated by a distance of 1.25 nm.Homework Equations Attractive energy (E) = -(A/r) *The constant A is equal to (1/(4∏ε0))(Z1e)(Z2e) where ε0 is the permittivity of a vacuum (8.85 x...
  30. C

    How do I measure/calculate the permittivity constant of materials?

    Hi, I am trying to figure out how to calculate the permeability constant of a lot of plastics by making solenoid (because that seemed to be the best method of doing so). I am currently using: μ=Ll/((N^2)A) to calculate that constant. Using this method I will only need an induction meter...
  31. R

    Programs Materials Science and Engineering/Chemistry, M.S. or PhD?

    Hi, I wanted to ask a question about graduate school, programs, and ask for any advice on what I should do/plan for my future. I'm currently a Senior majoring in Biochemistry (B.S.), minoring in Mathematics, with nearly 160 credit hours and a 3.78 GPA. I have a strong mathematical and chemical...
  32. A

    Plate materials in capacitors

    Hi I was wondering about an issue i thought about while attending a masters thesis dissertation earlier does the material of the plate (not the filling dielectric) affect capacitance (even if in the fringing level) ? Check the attached picture , for a better explanation
  33. J

    Colors of thin layers of materials

    Hi everyone. I have the following question: on passivated copper sheets used under high electric fields I found some color patterns I can't really explain. A possible explanation would be that there are some thin layers of material on top of pure copper, for instance the copper dioxide coming...
  34. Q

    How does voltage in wires affect conduit and nearby materials?

    Two questions here. From real-world problems, I was hoping someone smarter than me could explain the physics behind some issues I was told about. It's been a long time since I looked at an engineering or physics book, so please bear with me. 1) For a 3-phase motor, I was told that someone...
  35. G

    Engineering How great is the demand for materials science/engineering?

    Are materials scientists and engineers in relatively high demand compared to say, electric or mechanical engineers? Which degree would be best if I want to work in the "energy" field? And what kind of energy would each be dealing with?
  36. F

    Photon frequency boosting materials

    I've been reading about fluorescence and I understand how the band-gap accounts for reemission of photons at a longer wavelength. However, can a material store a photon, and then given an external energy source reemit at a shorter wavelength? I'm imagining an electrified "glass" that could...
  37. R

    Tensor based mechanics of materials books

    I was seaching mechanics of materials books, but i need them to be tensor based. Any sugestions?
  38. B

    Materials Science vs. Materials Engineering

    I'm torn between the two options, and I would appreciate it if someone with experience could help me contrast materials science with materials engineering. From what I've heard, materials science ultimately leads towards research, and development of new material. Materials Engineers, on...
  39. N

    Pursuing PhD in Computational Materials Science

    Hi all, I'm currently a senior studying chemical engineering. I'll be graduating this December. I am greatly interested in pursuing a PhD in materials science, and I am looking for programs that include an emphasis in computational materials (e.g. simulation of atomic structures). I am...
  40. B

    Looking for Heat Insulation Materials

    Hi I am looking for some thin and light heat insulation materials probably in a flat plate form. We intend to install this kind of heat insulation plate underground for separating different utilities. Any suggestion ? Thanks alot.
  41. B

    What are the best materials for underground heat insulation plates?

    Hi I am looking for some thin and light heat insulation materials probably in a flat plate form. We intend to install this kind of heat insulation plate underground for separating different utilities. Any suggestion ? Thanks alot.
  42. S

    Why Does Paper Char First Where It Covers Wood in a Composite Rod Experiment?

    Homework Statement A composite rod is made if copper and wood joined together. a piece of paper is filled in close contact with both rods bear the junction of wood and copper. The rod is passed several times through a bunsen flame. What will be observed and why? A: the portion of the paper in...
  43. P

    Book for magnetism in materials

    I am looking for a good book that covers magnetic properties in materials. I've taken E&M (we used Purcell), and it only covered magnetism in materials briefly.
  44. Roodles01

    Dia, para & ferromagnetic materials

    From another thread I think I understand that ferromagnetic material can exist any time, but dia & para magnetic materials exist only when there is an external field. My overview is Macroscopically ferro materials have to align their domains & can remain aligned when field is removed...
  45. E

    Study materials about Closed timelike curves (CTCs)

    I'm looking for some study materials regarding Closed time-like curves (CTCs). Be it a book, paper or anything other. It is highly accepted, but I'm particularly looking for a book that includes it and similar topics.
  46. A

    Methods used to measure the density of solid materials and liquids.

    Homework Statement I have to find two methods used to measure the density of a solid material and one method to measure a liquids density Homework Equations n/a The Attempt at a Solution got one method for the solids and have written this but my teacher wants me to find the...
  47. A

    Two Dielectric Materials in Capacitor

    Homework Statement A capacitor consisting of two parallel plates of area A = 7.3 m2 and spacing d = 0.150 m is filled with two parallel slabs of dielectric material of equal thickness and with dielectric constants 1 = 3.20 and 2 = 7.50, respectively. What is the total capacitance? k1 fills...
  48. S

    Any good self-teaching Calculus materials?

    Hey, next year I'm going into University. I will be taking a more computational-style calculus course, I believe the textbook will be by James Stewart: Single Variable calculus (my assumptions), and I will also be taking Physics. I'm wondering if you guys could give me a list of helpful websites...
  49. C

    Why are some materials transparent?

    Hey! I just saw a video on youtube from the guys at nothingham university (sixty symbols) where they explained that some materials are transparent due to the energy gap between the excited states of the electrons in the material. If photons come in at lower energies they will not interact with...
  50. M

    Move or attract large/heavy materials using polarisation

    I was just wondering if it was possible theoretically to move or attract large/heavy materials using polarisation. For example I've heard examples that if you have a charged rod ,and you bring it close enough to pieces of paper the charge on the rod will polarise the paper and then if that...
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