What is Materials: Definition and 981 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. 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...
  2. A

    Reflection of color in opaque and transparent materials

    Hi, The textbook I am using does not clearly explain why certain objects reflect certain frequencies of color. If the frequency of light matches the frequency of the opaque object it is shined upon, will it be absorbed or reflected? I'm thinking that it may be absorbed for the same reason...
  3. E

    Studying Engineering Materials Recommended Textbook

    Can anyone recommend me a good Engineering Materials textbook? Here is the course description: Introduces the physics and chemistry of engineering materials including metals, ceramics, polymers, and composites. Covers the relationships among the processing, internal structure, material...
  4. R

    Index of refraction and thickness of materials

    Hi, my current research is to determine the thickness and the index of refraction of semiconductor materials.. using reflectivity.. my adviser gave me the results of the sample by GRAPHS the reflectance percentage vs. the wavelength.. i know that i can measure the index of refraction.. if i...
  5. T

    Parallel plate capacitor with two dielectric materials?

    Homework Statement Use Gauss' law to find an expression for the electric field within a charged parallel plate capacitor with two layers of dielectric materials (?r1 and ?r2). (See attached image, this is for question 2a). The Attempt at a Solution My approach would be to split the...
  6. A

    Amount of of heat required for different materials to heat.

    Hi I am new to this Forum as well as thermodynamics. I need to find the amount of heat required to change the temperature of two given materials (iron bar and sand), from 25 deg C to 120 deg C. I have two steel tanks, one for holding each material. Both the tanks have the same dimensions (1m...
  7. S

    Thermal properties of materials

    Hey came across this question in my physics textbook. If the surface of a material is under compression, is it hot or cold relative to the body of the same piece of material? Unfortunately their explanation doesn't make any sense what so ever! Would anyone like to give an explanation that makes...
  8. C

    Can Light Travel Faster Than c in Diamagnetic Materials?

    The speed of light in vacuum is 1 / sqrt(mu_0 e_0). In matter, this is modified using relative permittivity and permeability, so the speed of light in matter is c / sqrt(k_m k_e). In diamagnetic materials, isn't k_m < 1? Then we'd have light going faster than 3 * 10^8 m/s in, say, nitrogen...
  9. R

    Constructing an Egg Drop Device with Limited Materials

    in physics we have to drop an egg 30ft and the only materials we have is 60cm of half inch thick clear tape, three sheets of paper, and four straws I am thinking about making helicopter blades for it and putting it in a modded paper water bomb with straws and paper bits as cushions but idk if...
  10. J

    Pressure formula for materials?

    Hi! Just checking reeally quick if there is any known formula for calculating out pressure on different materials. I have looked around on Google and son on but I haven't find one yet. The thing is: I have a pressure value in Pascal which I'm going to pump into a spheric material. And I wonder...
  11. G

    Mousetrap car design and materials

    Hello, I am building a mousetrap car for my physics class. I have looked at other threads for the best materials and designs but none of them have helped me much. I was wondering if anyone could give me something new to work with. I would like to have a three wheel design but my main...
  12. E

    Parts List = Bill of materials?

    Is a part list equivalent to a bill of materials?
  13. S

    Understanding Axial Forces and Section Properties in Strength of Materials

    Homework Statement I am having trouble with question 1 on the attachment posted. I understand that i need to get the area of the 2 bars. I am just not sure what to do with the forces. ALso i know the picture may be dark. P2 starts at point B and is pulling to the right and P3 starts at...
  14. E

    Nanophase components in nanoscale materials

    Hello, I'm self-studying a book on nanomedicine and in it, there is the following quote: "Nanoscale materials in general include hard and soft, wet and dry, and biotic and abiotic materials that are either nanostructured, or contain nanoscale and nanophase components." I guess my...
  15. R

    Math for Condensed Matter or Materials Science Theory

    I am a Physics major/ Math minor and would like to know what sort of undergrad upper-level math classes would be the most useful for Condensed Matter or Materials Science Theory?
  16. P

    Why does necking occur during tensile testing of ductile materials?

    Why does necking occur during tensile testing of ductile materials?
  17. J

    Galvanic protection of multiple materials maintaining electric connection

    I am looking for the best way to prevent corrosion between two different materials while maintaining electrical contact between them. Specifically, I am wondering about carbon fiber panels placed on an aluminum base and exposed to seawater. Carbon (graphite at least) has a much higher galvanic...
  18. C

    Importance of Graduate Quantum Mechanics 2 in Materials Science?

    Hello forum. I am a future M.S. Physics student (Fall 2012) that aspires to eventually obtain a PhD in some sort of materials science. Specifically, my interests lie in soft matter, thermodynamics and self assembled materials, but I am open minded to other directions. My M.S. school has the 2nd...
  19. E

    Mechanics of materials centroidal question

    Homework Statement a beam is 12 cm wide and 10 cm long. Find the neutral axis, the area centroid and the distance between them. Homework Equations Yc=h/2 The Attempt at a Solution Yc=10/2=5 cm. I can't seem to find the area centroid of a rectangle. Any help? Thanks!
  20. G

    Mechanics of Materials; I regarding this very fundamental problem.

    Why would the force P not always be equal to 60 kips? (I mean, since the structure is in equilibrium, and the members are rigid, can't we shift the two forces of 30kips each to the line of action of force P and conclude that P is always 60kips?) Thanks for your time.
  21. G

    How Do Forces Differ in Multiple Members of a Structure?

    Homework Statement (please see the attachment) Homework Equations σ=F/A The Attempt at a Solution I just can't figure out how to find the forces in the two members. Actually I thought the force in both members will be the same, but according to the problem statement it clearly...
  22. M

    Engineering Chemical vs. Materials Engineering

    I've been doing some research on majors and have narrowed my interests down to something involving a mixture of chemistry and math, possibly physics as well. From what I have found Chemical Engineering and Materials Science and Engineering seem to be closest to my ideal mix, though the...
  23. V

    The Impact of Ferromagnetic & Diamagnetic Materials on Magnetic Fields

    What is the effect of inserting any ferromagnetic, diamagnetic etc in magnetic field?? let me say there is a solenoid of turns per unit length n.magnetic field inside the solenoid will ~μnI. what will happen if an ferromagnetic substance like iron is inserted. How will it effect the magnetic...
  24. G

    Materials Science Help - Slip Systems & Resolved Shear Stress

    Hi everyone, I've taken a course at uni that may be a little bit over my head, and am pushing through an assignment for it at the moment in an attempt to do well. I've hit a bit of a roadblock on one question though, so am hoping that someone kind here can help me out! The question is...
  25. L

    Breakdown voltage of multiple materials

    I need to find an equation to figure out the breakdown voltage of layers of materials. In my case it will be air then glass then an inert gas. Any one have any info on how to get this. Thanks.
  26. B

    What causes materials to heat up when energy is converted?

    no its not a homework question it was in a quiz but i believe the teacher is wrong about it materials are heated when they absorb: -electromagnetic radiation of any type -infrared radiation only -microwaves and infrared only please choose and explain Thanks in advance
  27. P

    Strange behaviour of viscoelastic materials

    Dear Physics Forum, I posted this in the Mechanical Engineering Forum a while ago without any responses, but by looking at the other threads I suspect that it was the wrong place so I am posting it again here where it looks more at home (so apologies if i was wrong!). Can anyone explain...
  28. P

    Strange behaviour of viscoelastic materials

    Dear PF, Can anyone explain why viscoelastic materials behave differently at different strain rates? I understand the general explanation that the behaviour of viscoelastic materials is governed by a solid phase (elastic) and a fluid phase (viscous) and that at higher strain rates the...
  29. E

    Composite Materials: Matrix, Fibers & Mechanical Properties

    So I have been reading up on composite materials and have been geting a bit confused, from what I have read, composite materials consist of a matrix and reinforcement, the reinforcement can be fibers, I read that the way the fibres are placed will effect the machanical properties of the material...
  30. A

    What do materials engineers do? examples

    I'm currently in university and am taking supplemental math classes for an engineering major. I am currently undecided which engineering path to chose to major in as of yet. Materials engineering caught my eye and I just want to know some examples to work that materials engineers do. I have read...
  31. 1

    Materials Science - Derivation of Kapustinskii equation

    [b]1. The equilibrium bond length r0 in ion components (or salts) can always be obtained from the tabulated values of cationic, r+, and anionic radii, r-, respectively as r0=r+ + r- Show how on this basis, and that above (refering to the first part of the problem where i was to verify that...
  32. S

    Electromagnetic decay inside materials.

    Hey guys, back again for some help if that's okay! I've derived a formula for an electromagnetic wave entering a material, as \underline{E}e^{-\frac{x}{\delta}}e^{i(\frac{x}{\delta}- \omega t)} x=direction of propagation t=time \delta=skin depth As you can see this describes the wave...
  33. C

    Strength of materials - neutron stars

    I have a scientific background in materials science. However this is one type of material that we don't exactly learn about! Let's say you have a neutron star approaching a comparable mass black hole. As the neutron star approaches the event horizon for such a comparable black hole, tidal...
  34. Greg Bernhardt

    Medical How safe are dental materials?

    Over the past few weeks I've undergone a few operations. I had a root canal, crown lengthening and filling. Throughout these procedures loads of various chemicals and materials were put in my mouth. Many times I think some got swallowed or at least eventually leak into my system. Are these...
  35. L

    Torsion on materials of variable cross section

    New here, sorry if I'm in the wrong place or unclear, etc. I've been looking at torsion on solid plates and the torsion constant. I was wondering how to handle the torsion constant on a plate of changing cross section (e.g. there are holes drilled in it, changing the area of the cross section...
  36. C

    Bioenergy: how to measure the efficiency of different materials

    Hello all! I chose not to follow the given format, as my question is kind of unique. I hate to be one of those people who just create an account for one thread (as I usually try to avoid this), but my situation is quite urgent. I have a project due Friday, in which I plan to take different...
  37. M

    Heat and moisture transport on the building materials

    I have some questions about heat and moisture transport. 1. It is known that The water vapor permeability (μ) is a function of relative humidity (φ ) within the cavity of the porous materials: μ = B1 + B2 *exp(B3*φ ) where B1, B2 and B3 are coefficients of the water vapor permeability...
  38. I

    Materials Science Homework - BIG PROBLEMS

    I know there are set ways to post in this section, but I'm having so many problems with this class that I have to do it my own way. I decided to take Materials Science to help prepare me for graduate school and I am just struggling very much with this class. I haven't taken a physics class in 3...
  39. V

    Bicycle Trailer/Cot - What Materials?

    This is a future project, but I want to have everything once the weather warms up. Also, if this is in the wrong spot, please move it. The Plan: In the early summer I plan on going on a mini tour and would be camping along the way. I will use a tarp that's big enough to use as a pup tent and...
  40. M

    Very High Temperature materials

    Hi everyone, I have been trying to find some materials that could be used for very high temperature piping but have been struggling quite a lot. I have been looking at stainless steel alloys mostly. The specs are really tough: 1200 celcius of helium at 80MPa. My main concern here is...
  41. A

    Any (books, lecture notes or internet materials) that make you master the topics?

    You must have worked with some (books, lecture notes or internet materials) which make you master new topics. Could you suggest your choice to all? I want to follow others' track to study. If you got a nice material, you can generously upload and share the links of the lecture notes and...
  42. S

    Will a magnetic field pass through non magnetic materials

    Hi and thanks for helping me with these physics questions. Firstly, will a magnetic field pass through non magnetic materials as though it was air? For example, will a magnet still attract another magnet when copper or wood is placed in between it? I understand that if the material in...
  43. G

    Help with Statics and Strengths of Materials

    Hi, I just signed up with the forum. I have a degree in Mechanical Design, have been working as a drafter. It's been about 10 years since I've done any statics and wanted to re-learn this stuff by making a bucket loader for my garden tractor. The last few months I've been reading my...
  44. B

    Analytic calculations for piezoelectric materials

    Lets assume that all properties of a piece of piezoelectrical material are known, how should the analytical calculations be performed if the goal is to convert a vibration into electrical energy? What I'm looking for is the theoretical output voltage one can achieve for a known vibration. To...
  45. L

    Materials Selection problem for a torsion shaft

    Homework Statement A drive shaft tube for a rear wheel drive high-performance sedan requires a lighter weight unit than one made from conventional steel. The requirements are that the applied torque be 814 N-m (600 ft-lbs) the factor of safety be 2 or more and the maximum angular displacement...
  46. W

    Engineering Is materials engineering too narrow?

    I recently sent in my application for the materials engineering program at McGill University. I was all set on this career path but doubt is beginning to set in. Friends and family have been telling me that materials engineering is a dead-end, that the jobs are few, and growth minuscule. They...
  47. H

    Recycling of gas and other materials in galaxies

    Hello, I am reading a fabulous (though somewhat older book) called "Intelligent life in the Universe" by s. Sagan and I.S. Shklovskii. They describe intense magnetic fields extending from the galactic core that channel interstellar gas and dust into the spiral arms which are the primary site...
  48. H

    Need a list of core materials and their permeabilities

    Anyone know where I can get a list of different core materials and their permeabilities?
  49. P

    Statics - Mechanics of Materials, check my work please?

    Could someone please check this for me? I attached a rough free body diagram of the whole frame. Any help is appreciated. Homework Statement The member ACF of the frame loaded as shown is connected to member BCD by means of a smooth peg and slot C with force P = 930 N at point D...
  50. N

    Calculate the R-value of the stack of materials

    Homework Statement Calculate the R-value of the stack of materials whose total thickness is made up of the individual thicknesses: material 1; k = 0.123 W/m/K, thickness = 0.103 m material 2: k = 0.234 W/m/K, thickness = 0.092 m material 3: k = 0.345 W/m/K, thickness = 0.081 mHence...
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