Materials Definition and 988 Threads

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.

View More On Wikipedia.org
Recent contents Top users
  1. L

    Feynman lectures - elastic materials - eqn 39.22

    I'm reading Feynman Lectures on Physics Volume 2 Chapter 39 on elastic materials. Equation 39.22 relates the elements in the elasticity tensor to the Young's modulus and the Poisson's ratio. I have no clue on how to get these relations myself. For example, for C_xxxx, I think it should tell...
  2. P

    Choosing the Best Material for a Transparent Casing for Neodymium Magnets

    Hello I am building a casing for Neodymium Magnet. I don't want to shield the power of the magnet in any way, and I want the casing to be strong. What is the best material that i can use? It also has to be transperant. Will plastic effect the magnetic field and by how much. Will the...
  3. C

    Why do some materials appear darker when wet?

    I say 'some materials' because it is not true for all. Usually, clothes appear darker when wetted, but I have one pair of trousers that actually goes ligher when water spashes on them, so it is not 'always'.
  4. B

    Trussel buckling,question from mechanics of materials

    Ok,first of all ,I'm sorry for any further language barrier things,I study in a non-English speaking university,and I might do a mistake in translating some technical terminology. So,the problem is from mechanics of materials,buckling loads.This subject gives me nightmares as it is,I can barely...
  5. Greg Bernhardt

    Magnetic Materials: What's Most Attractive?

    My sister has a question: thanks!
  6. I

    Effective masses of the insulator materials

    What are the effective mass of conduction band (mc) and valence band (mv) of insulator material Al2O3. Kindly tell me your reference
  7. Y

    Calculating the Ratio of Electromagnetic Wave Speeds in Vacuum and Materials

    Homework Statement Electric and magnetic fields in many materials can be analyzed using the same relationships as for fields in vacuum, only substituting relative values of the permittivity and the permeability, ε = κε0 and μ = κmμ0, for their vacuum values, where κ is the dielectric...
  8. R

    What causes materials to be lossy and how can this loss be measured?

    Hi, I'm trying to understand what makes materials lossy and how to measure that lossiness - this is for either/or electromagnetics or acoustics. So far, I haven't really found good explanations/resources other than that a complex permittivity can cause loss. However, how do viscosity or...
  9. D

    Strength of materials (Euler Theory)

    A bar of length 4m when used as simply supported beam and subjected to a uniform distribution load of 30kN/m over whole span, deflects 15 mm at the center. Determine the crippling loads when it is used as a column with following end conditions. a)both ends pin-jointed b)One end fixed and other...
  10. D

    Strength of materials (shear and moment)

    R at B = 5.0625 R at A = 8.5kN-5.0625kN=3.4375kN x/0.9375=(0.5-x)/4.5625 x=15/176 but moment near x there i get different from both side: from A = 2.431kNm from B = 2.346kNm is there something wrong?
  11. K

    Forces on Materials Homework: Q&A & Examples

    Homework Statement Some question about forces on materials: 1.What is "alternating load"? 2.What are the effect of forces (static,dynamic,impact,fatigue & alternating load) on materials?(Give an example for each force) 3.What are the limits of Hooke's Law?How does the graphs look like? Please...
  12. N

    Permanent effects on electron spin by magnetic materials?

    Hello all, I feel somewhat strange posting on this forum because I'm majoring in biology and we're supposed to be the enemies of physics, but I've come across a question that I can't seem to find an answer to; this is actually in regards to independent research. Does instantaneous or prolonged...
  13. R

    Typical building materials for an office building

    Hello all, I'm modelling an office building using Google SketchUp to determine its cooling load during summer. Unfortunately, the default building materials (external walls, floor, roof etc.) seem like they are for residential buildings. Can someone please tell me what are the typical...
  14. S

    Extremely Advanced Materials from Manipulation of Space-time

    Hello everyone, I'm a new member of the Physics Forums, and not a physicist by specialization, so please have mercy :-) I'm a linguist by training, and by profession a writer of fiction and role-playing games. I'm currently in the process of getting my first science-fiction novel...
  15. A

    Computational mathematics materials

    I'm trying to find notes and material on a course, which, strangely, i can't find anywhere (the course). It's called "Computational Mathematics", and it deals with numerical solutions of ODEs, initial value problems,boundary value problems,reliability,stability and convergence of numerical...
  16. U

    Low single charge carrier density materials?

    Hello all, I am trying to identify materials having a single dominant charge carrier having extremely low (on the order of 10^15 cm^-3) concentrations. Metals and extrinsically doped semiconductors, while both possessing a single dominant charge carrier (electrons or holes), tend to have...
  17. N

    Why don't dielectric materials radiate?

    Say we have an electromagnetic wave propagating inside a dielectric material. Of course physically this material will radiate, due to the little electrons being excited by the wave (their wiggling is also the physical cause of the \epsilon \neq \epsilon_0), and oscillating dipoles radiate. And...
  18. B

    Snell's Law in birefringent materials

    Homework Statement I'm trying to work out what happens why light hits a boundary between two birefringent materials with their optical axis perpendicular. It's hard to describe so I've attached a diagram. The upper wedge has an optical axis pointing upwards, the lower wedge has it coming out...
  19. K

    Dispersion relation of amorphous materials

    Hi, I am trying to find dispersion relation of amorphous material (using data obtained by molecular dynamics simulation). As it is not periodic system one can not find it by standard method of diagonalizing the force constant matrix. I think one can do it by taking Fourier transform of...
  20. S

    Understanding transformed sections of composite materials

    hi! I'm hoping to have something cleared up if i have a beam made out of two materials, and it gets bent, and i need to analysis the transformed section for whatever reason, i have learned that you need to sort of 'pretend' that you're looking at a beam of a single material. in order to do...
  21. D

    How Is Displacement Calculated in a Compound Bar Under Load?

    Homework Statement A steel bar and a brass bar, both of 36 mm diameter, are joined at point C to form a compound bar. Neglect the weight of the bars. Determine the displacement (in mm) of point D due to the loading. The forces are PB=54 kN and PD=117 kN at points B and D respectively...
  22. Drakkith

    Hazardous Radioactive Materials

    I've seen a lot of talk recently about radiation and radioactive materials. I was wondering what the major issues with storing these materials are and what materials are posing the most risks. Which ones are the biggest hazards? Products that are gases instead of solids/liquids? Ones that...
  23. S

    What are good insulation materials?

    Types of metals, plastics and others like fiber glass. Also I have another question. How do I calculate how long it takes to heat liquid up with different amounts of energy. Say from -40c, how long does it take to heat oil to 71c with a 120volts. This is bare bones, but I just want to know...
  24. T

    Multi-region Finite Difference- Interface between materials

    I am writing a multi-region diffusion code. The two regions have different material properties, so the analytical solution shows a discontinuity at the interface between the regions. As can be seen here: The numerical code I am running is (Mathematica): While[converge > .00001...
  25. T

    What Are Non-Fiberglass Materials That Withstand Over 500 Degrees?

    hi,,, i work in an industry ,of were we produce aluminuim alloy which is rolled out at temperatures of 500 degrees , we are using a fibre glass based material for interleaving (stop metal to metal contact ) which as a tendency of breaking down to a fine powder substance , which then becomes an...
  26. S

    Radiation and penetrability of materials

    Is it possible to calculate whether or not beta decay from a given beta-source can penetrate a material of a certain thickness? I'm thinking something along the lines of first calculating the average eV of the decay (What do you need to know about the source to do this?), and then looking...
  27. A

    Why Do Ceramic Materials Exhibit Different Brittle Fracture Points?

    Hi I have 5 different experimental data of a ceramic undergoing compressive stress, and I've graphed them. There are some significant differences among these graphs compared to other materials I've compared (aluminium, pvc etc). Each has multiple fracture points etc...my question is what...
  28. A

    What is a readable intro text for electronic materials (material science)?

    As the title, Anyone know any good readable intro book of material science, especially dealing with electronic materials(semiconductors,etc.)? I am a Physics major in sophomore year.. I took Calc 1-3, linear algebra, ODE and some intro EM and modern physics
  29. S

    Optical Properties of Materials presentation

    Hi everyone, I'm trying to gather some ideas of subjects for an oral presentation in my Optical Properties of Materials class: I'd love to find something pleasant or at least nice to develop (like I heard "how a cameleon changes color?"^^), not too theoretical if possible... And with some...
  30. M

    Refractive index of materials at rf frequencies to make a smaller wire antenna

    I would like to ask a few questions. Does a table of refractive indices of materials at rf frequencies (say for TV) exists? Is there a way for me to estimate it for some materials? Are the refractive indices of these materials higher? Will those materials have low absorption losses at these...
  31. M

    Composite Materials: Determining If a Composite is Possible

    Hi, I am trying to understand some more on composite materials and i have a question. Let's say i have two materials and i want to produce a composite from those materials. How can i check if a composite is possible from these materials? I have found an equation on the web but i am newbie on...
  32. N

    SERS Substrates for Adsorbing Biological Materials

    I'm interested in coating a coverslip with a thin layer of silver for SERS. I intend to grow a salmonella biofilm on it afterwards and get the spectrum. Does anyone have any experience with SERS and if so can you give me your advice for preparing SERS substrates to adsorb biological materials...
  33. B

    Review Materials for Upper Level Physics Courses

    I'm looking for any recomendations for review materials for upper level courses, particularly QM and solid state. I graduated in 2008 will a degree in Physics education, and as a result have a decently strong theoritcal background, however as you might imagine some of the education classes did...
  34. B

    Understanding the Temperature Difference of Metals and Other Objects

    Why are metals colder than other objects at room temperature? Or is my assumption wrong here. Whenever i touch a metal bar in my classroom i find it much more colder than my hand feels in the air. I know that metals have heavy atoms, thus making oscillations of them very slow, frequency...
  35. G

    Can you weaken a magnetic field with the peresnce of ferris materials?

    suppose you had a magnetic rod with a diameter of 1" and around 18 inches long, and the north and south poles are oriented at the ends of the rod. if you stuck the north end of the magnet to a piece of steel would it effect the magnetic pull at the southern end? if the north and south poles...
  36. S

    Majoring in ChemE or Materials Science Is it hard to get a job with only a BS?

    I still have a long ways to go but it seems like many of the jobs require a master's degree. Due to some past mistakes, I may not be able to maintain my 3.0 that I currently have all the way through until graduation.
  37. 7

    Exothermic chemical reaction materials

    Hi all, I'm looking for two material to produce an exothermic reaction of 180-190 C. I'd prefer the materials to be cheap in larger quantities (think mass production). Safe, other than the heat concerns. Not extremely corrosive, toxic... Easy to clean once combined. Prefer materials that...
  38. J

    Hibbeler Mechanics of Materials

    Hey guys I'm looking through my Mechanics of Materials book (Hibbeler 8th ed.) and am quite confused at the section on shear and moment diagrams. I thought I grasped it very well in statics but I guess I was wrong. Anyways I am looking at Example 6.4 and it asks for the shear and moment...
  39. L

    Understanding ESD Mats: Non-Wool Materials & Discharge

    I don't understand how exactly ESD mats work. They prevent build up of Electrostatic charge. So any non-wool material would qualify as an ESD mat? Do ESD mats also help discharge an already build up ESD, like a person clothed in sweater and charged up to couple of Kilovolts?
  40. J

    Photoelectric Materials Homework: Calculating Voltage for Extinguishing Current

    Homework Statement A multi-akali alloy is used as the photocathode material in a photoemissive electron tube. The work function is 1.6eV a blue light of wavelength 420nm is incident to the photocathode. What should be the voltage and polarity to extinguish the current Homework Equations...
  41. P

    Grain Size, Polarization & Resonance Frequency in Microwave Technology

    development of microwave technology enhanced the the used of ferroelectric materials. how to relate the growth of grain size with polarization and also effect on resonance frequency.
  42. G

    Mechanics of Materials - Deflection of a rigid bar

    Homework Statement http://img.waffleimages.com/5b5524d885644e9f1c76a800c4b0701a0606268a/problem6.jpg (The image will not work unless it is copied and pasted into the address bar) I am given this drawing and stress v strain diagram, and am told to find the deflection, ∂, at 4 (the end of...
  43. O

    Sorting Different Materials Balls By Weight: Most Efficient Method

    I have 5 different types of balls made out of different materials, all similar but not identical in weight, and all of the the same size. What is the best mechanism to sort these by weight? I can use any mechanical device to sort these balls, such as seesaws, etc. What is the most efficient way?
  44. chris2112

    The nature of light from colored(visual) materials

    My question stems from the visual perception of color. First I'd like to clarify what we're seeing. When we see that a material is a certain color does this mean that it's constitute atoms are continuously absorbing certain wave lengths/energy levels of light and blocking out/bouncing the left...
  45. J

    Mechanics of Materials Explanation

    I was reading through my mechanics of materials book (Mechanics of Materials 8th ed. R.C. Hibbler) learning about stress and came across example 1.6 pg. 28. while most of the example makes sense the last bit of part b) confused me. I am unsure as to why for Pcd he only showed the 22 kN force...
  46. D

    Can I Accurately Test Hardness of Materials Without a Microscope?

    Hi I'm not a physicist but I'm looking for a simple way to test the hardness of different materials. I need to do a demonstration and collect results with a science class, the task sheet that accompanies the lesson says to place a cloth over the materials and hit them with a hammer. I would...
  47. O

    Which Materials Have Optical Activity?

    Which of the following materials have activity Optical ? i know it must have an Chiral molecule,but still i am not know in this list who have it. thanks for help.
  48. C

    Online Mechanics of Materials Resources for Basic Equations

    Does anyone have any good online reference sources that derive the basic equations from Mechanics of Materials such as angular deflection of beams under torsion, stress on cross section due to moments, etc. all the easy basic stuff. I took those classes a long time ago and I don't remember...
  49. M

    What Causes Color Changes in Electrochromic Thin Films?

    as you know ,Electrochromism is the phenomenon displayed by some materials of reversibly changing color when voltage is applied. i am working on WO3 thin films.i know that redox will happen when voltag is applied. I am interested to know ,changing in which paramete is caused to thin films...
  50. S

    Exploring the Fate of Energy in Plastic Deformation of Materials

    I have a simple question that I cannot find a compelling answer for. If I expend (let's say) 100 kJ bending a steel bar into a right angle, where did the energy go? Some will obviously be expended as noise and heat. Will the rest be expended in the plastic deformation of the bar? No useful...
Back
Top