What is Metal: Definition and 999 Discussions

A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.
In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure.
In chemistry, two elements that would otherwise qualify (in physics) as brittle metals—arsenic and antimony—are commonly instead recognised as metalloids due to their chemistry (predominantly non-metallic for arsenic, and balanced between metallicity and nonmetallicity for antimony). Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved.
In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than helium, and not just traditional metals. In this sense the first four "metals" collecting in stellar cores through nucleosynthesis are carbon, nitrogen, oxygen, and neon, all of which are strictly non-metals in chemistry. A star fuses lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. Used in that sense, the metallicity of an astronomical object is the proportion of its matter made up of the heavier chemical elements.Metals, as chemical elements, comprise 25% of the Earth's crust and are present in many aspects of modern life. The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge construction, as well as most vehicles, many home appliances, tools, pipes, and railroad tracks. Precious metals were historically used as coinage, but in the modern era, coinage metals have extended to at least 23 of the chemical elements.The history of refined metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the 5th millennium BCE. Subsequent developments include the production of early forms of steel; the discovery of sodium—the first light metal—in 1809; the rise of modern alloy steels; and, since the end of World War II, the development of more sophisticated alloys.

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  1. T

    How to attach clamp to metal bar?

    Hi, I am trying to find a way to attach the clamp to the metal bar seen in the picture so that they become a rigid unit. I am not sure what is best way to do it. Drilling somehow? screws where? if anyone has a suggestion, please let me know. The metal bar in black seen in the picture is...
  2. Dale

    I Tunneling of light through thin metal films

    Metal is normally opaque in the visible range of the spectrum, so that makes it a good "barrier" to photons in that range. But if a film of metal is made thin enough then it is semi-transparent. Is this an example of tunneling or is it based on some other principle? Does the attenuation as a...
  3. G

    I What radioactive metal glows white hot all the time?

    1961 My father worked for a well drilling company called, Schlumberger in Lansing MI. One day he told me the company has a radioactive piece of metal that glows white hot all the time we keep it in a cement box in the ground inside a metal box with a lid. Sunday Schlumberger was closed and no...
  4. A

    B Can I use this method to charge a metal sphere?

    Consider a metal sphere connected to one end of the battery and the other end of the battery to be connected to the ground. Does the metal sphere become electrically charged with this method?
  5. R

    Density calculation sometimes can be confusing

    Ok, let's compare two cubes of lead. First lead cube weigh 6078 grams and its area is 3376 cm. The second lead cube is smaller and lighter at 5216 grams and 2713 cm area. The density of the first lead cube which is the bigger and heavier lead (by dividing its weight with the area) is 1.800 g/cm2...
  6. sophiecentaur

    Misc. Why do pyrolytic ovens require the removal of metal racks for cleaning?

    I just tried cleaning our new oven with the pyrolytic function. Incredible results and it certainly warmed up the house. But the intructions insisted that I remove all metal racks etc. I have to wonder why, bearing in mind that the temperature can't melt the stainless steel. This increases the...
  7. D

    Misc. Levitating Metal with a Solar Cooker: A Feasibility Study

    I would like to build what is usually used for heat production and is called a solar cooker. However, I would like to use it to try to levitate a piece of metal. Here are my assumptions: A. aluminum density = 2.7 g / cm^3 B. Sunlight intensity on Earth's surface is about 1000 W / m^2 C...
  8. ergospherical

    Electrons escaping a metal surface

    In the low temperature limit ##\mu \approx E_F## and the Fermi-Dirac distribution is ##n(E) \approx g(E)/(e^{\beta(E-E_F)}+1)##. An escaping electron contributes ##\Delta j_z = -ev_z = -ep_z/m## to the current density. How can I calculate the rate that electrons escape at? I can't see how to...
  9. E

    Electron encountering metal surface (1D Step potential)

    I am struggling with how to go about this; in particular, I'm not sure I understand what state is being alluded to when Ballentine says "For an electron that approaches the surface from the interior, with momentum ##\hbar k## in the positive ##x## direction, calculate the probability that it...
  10. abdulbadii

    Measuring thermal conductivity of a metal

    What'd be practical method and/or portable, simple tool (like sort of electricians' multimeter) to meter the heat conductive constant of a metal?
  11. Kupa140

    Analyzing the Force of Two Disk Magnets on a Metal Plate

    The situation is as follows. We have two disk magnets. One is fixed on the ground, table, or surface and has the north pole facing up. Then we have a metal plate fixed on the vertical axis rod or something similar such that it can't move up or down, but only rotate horizontally with as less...
  12. C

    Looking for ways of joining metal and plastic

    i have a plastic handle and want to join it with a metal body. i can join it with heat stacking method i have find a product who done done that. is there any other way to join permenently?
  13. LarryS

    Formula for Resonant Frequency of 2 Metal Coaxial Cylinders?

    Consider an LC circuit consisting of a parallel plate capacitor and a solenoid inductor in series. The formula for the resonant frequency of this circuit is 1/√(LC) where “L” is the inductance of the solenoid and “C” is the capacitance of the capacitor. Now consider a high-frequency cavity...
  14. B

    I Metal drinking cup is stuck inside a pressure cooker

    the steel glass is stuck diagonally inside the press cooker, getting it out by brute foce didn't work and neither are we able to rotate it. Washing it with soapy liquid didn't work either. Any ideas on how I can get the glass out?
  15. Pushoam

    Capacitance of a parallel plate capacitor with a metal plate kept inside

    Because of the plate P, the capacitor becomes a piece of conductor. It contains zero net charge and has 0 potential difference. Hence, the capacitance is ## \frac 0 0 # # that is undefined. The capacitance of a capacitor is defined as its capacity to store charge when a potential difference is...
  16. C

    Discontinuous voltage graph for bullet going through metal coils

    For this problem, The solution is, However, dose anybody please know why the graphs for ##V_1## and ##V_2## are discontinuous where they cross the time axis? Many thanks!
  17. lxhull

    Specific Heat Capacity of a metal bar placed into water

    Previously solved thermal energy gained by water as Eth= 0.15(4180)(17.6) = 11035.2 J Not sure if its relevant
  18. DaveC426913

    Engineering What might I expect as a Junior Metal Millwright?

    Canada here. I've been in software dev for 20 years (and have been doing data entry in healthcare for the last four years, but it's only temporary.) Every time I consider a new career, I end up in software dev. I'm considering going against the grain of what I know and pushing my envelope. I'm...
  19. X

    I Trying to identify a weird metal found on a beach

    This object, about the size of a tennis ball was found by my brother. It's metal. It's very hard. Cannot scratch it with a Stanley knife. Cannot break even a small piece off using pliers. Thrown with force at concrete and undamaged. Relatively heavy. My brother estimates similar weight to lead...
  20. alukhm

    Wood/Glass/Metal Magnet Inside a Shell containing Ferromagnetic Metal

    Hello all! I have a earring project with magnets involved but no magnet expert involved :( Here are a few stupid questions I hope someone can help us with! BACKGROUND: We are designing magnetic earrings. The earrings are meant to clamp the ear with 3 different levels of pressure. The magnetic...
  21. B

    I Emission of light from incandescence of metals

    a. We know metals emit EM radiation upon heating or electric current. I'd like to understand more fundamentally how this phenomenon takes place, on the basis of the basis of band structure, and which electrons are involved ? b. Classically, charges emit radiation when accelarating or...
  22. P

    I Electrically Shocked by Metal? Exploring the Seebeck Effect

    Whenever I touch to a doorknob or any other metallic object I get electrically shocked. Does this occur because of temperature difference between me and the metal? Is it similar to seebeck effect?
  23. hilbert2

    Reactive metal wires in a fuel oxidizer mixture

    Suppose there's some slow burning pyrotechnic mixture like KNO##_3## with powdered charcoal, and several really thin threads/wires of magnesium metal (or zirconium or magnesium/aluminum alloy) are made go through a pile of that mixture. Now I would guess that because a mixture of finely powdered...
  24. thedubdude

    I Why does metal moving though a magnetic field slow down?

    A piece of metal moving West to East in a North to South fixed magnetic field slows down...but how? Yes of course eddy currents are set up in the metal and these currents generate their own magnetic field which somehow slows down the moving metal piece...but how does this actually slow the...
  25. A

    I What Causes the Darkening of Metal Bucket Color at High Temperatures?

    This is the color of the metal bucket when it's not hot. But whenever it is hot, the red changes to dark, and then back to red again when it is not hot. See the following youtube where I just threw the fake money at the bucket (see background below). Can you explain how the phenomenon work...
  26. Y

    3D Printed Metal Custom Tool Request

    Does anyone on here have a 3D printer for metal? I'm looking to get a custom made socket wrench fabricated for 10 mm bolts or nuts. I'm looking for one that is extremely low profile. I don't care about the drive style (1/4", 1/2", 3/4", 1", external hex etc). The smallest mass produced one I...
  27. A

    How long before this type of metal roof will melt in a house fire?

    Given a gauge 25 (0.02" or 0.5mm) metal roof roll formed made from hot-dip galvanized cold rolled mild steel. How long can these thin metal roof melt in a typical house or office fire with typical fire load? I read conflicting information. Some roof contractor said these thin gauge 25 metal...
  28. A

    I Molten metal flow due to high currents

    It is mentioned in the book "Ampere-Neumann Electrodynamics of Metals", Peter Graneau, that Carl Hering in 1923 operated furnaces by passing high current through the molten metal pool. He observed molten metal flow due to the currents. How is the conductor motion explained?
  29. T

    Electrical Calibrating a metal leaf or pith ball electroscope

    I'm trying to build a DIY metal leaf or pith ball electroscope. I want to provide it with a circular arc voltage scale visible directly behind the (deflected) ends of the leaves. To calibrate the scale with ballpark accuracy, I want to determine the charge density upon the leaf pair (or pith...
  30. aibolot

    Alternatives for Metal Spring?

    Hi everyone, Any alternatives you know for metal spring? The idea is to find a replacement for a metal spring that has the same efficiency in bouncing an object that's hung by the spring. Any input of a kind would be valuable. TIA
  31. L

    B Does there exist a metal that is 100% unrustable?

    Is there a metal that can never rust? I am tired of cars rusting even with antirust treatments.
  32. Wesley souza

    Doubts about deep drilling in metal with an HSS drill

    hello my friends, the other day I read that the barrels of firearms before 1930 (the birth of gundrills) the barrels were forged from plates until they became a tube and later, they were made from steel bars that were drilled with welded HSS drill bits. Does anyone have experience with the deep...
  33. A

    I Question regarding Electrical Resistivity of metal vapors

    What is the electrical resistivity of Caesium vapor? What is the electrical resistivity of Potassium vapor? Sorry there are no support material or reference links for this. Just a question. The unit must be in Ohm-meter.
  34. moriah

    What is the Source of Strange Sewer-Like Fumes Causing Reactions?

    I am in the need of airtight materials. Naturally, metal came to my mind. Metal is used in jar tops to create “airtight” seals. However, as I contemplated how the tops must expand slightly as they are screwed down towards the glass part of the jars, I wondered if this expansion compromises...
  35. J

    How many atoms are in a given mass of metal?

    Hi all, This may be simple chemistry, but I haven’t engaged this topic for a very long time. I have an experiment where I need to measure the masses of some elemental (99%pure) metal cubes and I also want to know how many atoms of each element there are within them. From memory, Avogadro’s...
  36. mcas

    Evaluate reflectance of an aluminum mirror

    Note: for some reason frequency on this lecture is indicated by \omega. I wanted to calculate the reflectance using one of these equations that were given to us during the lecture: R=1 where \omega < \omega_p...
  37. abdulbadii

    How to make hard metal toolkit handle from Polyethylene tube

    How do we make hard metal toolkit handle from high density Polyethylene tube/pipe inside which the tool near end is united, glued by some material (black as seen for now, try to give pic. later on)
  38. Steven Bolgiano

    I Thermodynamic Pros/Cons coating light metal tanks with rubber

    Hi Folks, I promise there is an actual question at the end of this note. I couldn't see where to attach images on this forum page, so here is a link to a rough illustration and a photo of the project site in progress (the cabinet for the digester is partially built)...
  39. E

    What happens when a conducting sphere rubs against metal?

    I know that metal is a "reservoir" of electrons, whereby electrons can flow out and in easily, so when conducting sphere is rubbed against metals, is there even a resulting charge on the conducting sphere?
  40. 1

    Is it safe to cover a floor lamp with an Aluminum metal pie plate?

    Please see the image below. I'm trying to convert my IKEA NYFORS floor lamp into a reading light, by covering the top with an Aluminium pie plate. Will this be a fire or electrical hazard? Does anyone foresee any dangers or risks? As I have 3 of these floor lamps in my attic, I don't want to...
  41. M

    I Free electrons in an accelerated metal?

    I take a conductor and expose one side to a nearby region of negative charge. The metal's free electrons are repelled, and many collect at the opposite side to the charged region. High School stuff. Okay, so now I accelerate the metal in one direction. What happens to the free electrons...do...
  42. J

    Understanding the Interaction Between a Charged Rod and a Metal Sphere

    (A) incorrect, because opposite signs attract, and the sphere would've been drawn to the charged rod. (B) correct, according to the answer key, but if the charge of the sphere and the charge of the rod are the same, then wouldn't they repel each other? I'm confused as to why this is the correct...
  43. yucheng

    How does metal sphere determine the potential of the plane by symmetry?

    The answer given states that: The entire x-y plane is obviously at the same potential since all the fields are strictly perpendicular to it (draw a diagram if youre confused). Since we choose the sphere to be at potential zero, the point on the sphere which cuts the x-y plane is also at zero...
  44. L

    Chemistry Finding the formula of the metal

    I haven't gone into a solution cause I found this question confusing
  45. Johan L

    EM re-radiation from a metal object (antennas)

    Consider the following situation. Two identical monopole antennas are placed in a field with distance d. One of them is used to receive signals and the other is disconnected and can therefor be considered to be just a metal rod (my guess). A plane wave of a single frequency is coming from a...
  46. G

    RF transmitter inside a metal enclosure, re. reflections

    wavelength is .3 m to 6m, a 3m waveguide can do up to the 6m λ, so it will reflect all the frequencies concerned
  47. kolleamm

    Can metal fluid contract under voltage?

    I was told there exists a metallic fluid that contracts when a voltage is applied to it. Does anything like this actually exist?
  48. P

    Difficult capacitance problem -- 3 long concentric metal cylinders

    A solution I found online claims that the effective capacitance between the middle and inner shell can be seen as: C (effective) = C1 + C2, where C1 is the capacitance between the inner and outermost shell, and C2 is the capacitance between the middle and outermost shell. Apparently C1 and C2...
  49. J

    B Will Metal Obstruction Affect WIFI Reception of My Sonos One Speaker?

    Hi! I’m doing a little mod/add-on to my Sonos One wireless speaker (don’t ask what and why, long story 😅). My question is, how do you think this construction may affect WIFI-reception? I’ve marked the places where I think the antennas are, do you think the metal wire may interfere in some way...