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.
Hello
Can ultrasound pass through metal?
How much of it can pass and how thick the metal can be?
I couldn't find anything online, I only found some contradicting and unclear information.
Hi,
So I recently had to get an MRI. I forgot to take off my wedding ring, but the technicians said it's ok "if it's real gold".
I told them it was white gold (which is an alloy of 58.5% gold and the rest is other metals). They said it was fine, but later told me they didn't really know what...
I'm doing some calculations on deforming of metal sheets. I have a formula for calculating the force needed to bend metal sheets. Does anyone have suggestions on where I can find more information? What I would like to end up with a way of calculating the force needed to deform metal sheets such...
What protocol should I use to get a good stable 100nm Au adhesion onto a Si substrate using electron beam evaporation? I've heard talk of primer layers of either Cr or Ti at around 5nm thickness, as the typical way to do it.
Which material should I choose? What the advantages or disadvantages...
Homework Statement
Homework EquationsThe Attempt at a Solution
Potential at the center of conducting charged sphere surrounded by a grounded shell
If I take another sphere of charge –q of radius a with uniform charge density, then the potential on the spherical region from the radius a to...
Since positive charge on the photocatode increases work function of electrons, does charging metal photocatode negatively decrease work function? If not, why?
Homework Statement
Two large, flat metal plates are held parallel to each other and separated by a distance d.· They are connected together at their edge by a metal strip. A thirt plastic sheet carrying a surface charge \sigma per unit area is placed between the plates at a distance 1/3*d from...
Hi, I am researching maraging steel material used in additive manufacturing and there are references in the literature to a mesostructure. Can anyone clarify?
Hello.. (see 3 colored pictures below to illustrate the question)
I have a pair of eyeglasses with screwless spring hinges that uses spring steel metal strip (see full pictures below). I’d like to understand something about it. When the temples are fully opened.. the spring metal strip are in...
Hi,
If some voltage is traveling from a low conductivity metal to a high conductivity metal, does it impose limitations on the high conductivity metal such that it will only do as much as the low conductivity metal?
Homework Statement
Homework EquationsThe Attempt at a Solution
Since the dependence of resistance upon the tem. is different for metal and semi - conductor ( increase of tem. decreases semi - con. resistivity while increases metal's resistivity.), option c is not the right answer.
Since...
Hello, I've been thinking about if amorphous metal (aka metallic glass) could created by using regular electroplating or if it has to be created by rapid cooling of the metal after molten. There is a method which a thin layer of metal powder is applied to a flat surface where a laser beam melts...
I am trying to understand the construction of CVT Metal belts that are made up of steel elements and some rings. I do not understand the full construction details of the belt.
The most detailed information I have got ever is in this PDF on page 5...
Hello all
First time on the Math side of this great Forum.
I need to do a correlation study.
There are 3 methods to measure Form Error of a round metal part.
The base line is the traditional measuring method that is laborious but of the highest accuracy.
A cnc machine measurement machine...
I'm working on a public area audio system where we need to install our horn speakers on big height as per their installation requirements.
We designed a metal pole as described:
Pole consists of two poles: 1) a 7.5 meters height, 10" diameter, 6mm thickness. 1.5 meters are to be buried...
Hello,
I got this problem but I don't know How can Find Heat loss (or gain) - Q3 - from the curved surface of the metal rod to the surrounding.
This is the problem:
A metal rod, of diameter (d) and length (L), runs between two hot walls at temperatures, T1 (Wall
1) and T2 (Wall 2)...
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I'm curious to know, whether it is possible to produce electricity by moving a piece of metal over a magnet (i.e a immobile magnet and a moving piece of metal close to the magnet), and how this would be done in practice.
HI,
I have application where i need to lift metal plate, 3kg weight, ( 3mmX 15mm), 250degree.C hot, for the period of 1min and put it back. For lifting purpose i am using actuators. As i have no opportunity to make hole in plate i have to use magnet for lifting purpose. I got Electromagnet...
Homework Statement
Homework EquationsThe Attempt at a Solution
I solved the first part.
I = 4πσV/(1/a - 1/b)
Here, it is solved assuming that both the shells have positive charges and the charge flows from the inner shell to the outer shell .
So, in the part c, it is assumed that each...
Okay, I have a very simple question that...Suppose we have a very wide cube(dense and hard)...We place two persons at each of its ends...One the persons strikes its surface at one end. Now this person A will hear the sound due to vibrations of that end's surface (which further vibrate the air...
Homework Statement
Homework EquationsThe Attempt at a Solution
For drum A,
Eqn. of COM motion gives,
## T(\hat y ) + Mg (- \hat y ) = M a_A (\hat y ) ## ; ## a_A = - |a_A| ## eq (1)
I need to know T here for getting ## a_A ##.
For drum B,
Eqn. of COM motion doesn't give...
Hello, I am a civil engineering student undertaking a project to investigate the effect of pipes and pipelines beneath the ground on the urban city environment above. In order to proceed I am designating a simple metal detector. Due to low depth capability of all commercial metal detectors mine...
Not only are lead nuclei heavier than gold ones (207 vs 200), but the atoms are smaller (ionic radius 119pm vs 137pm). There is every reason for Pb to be heavier. Why is it lighter? (11.34 vs 19.31 g/cm^3)
They both have a FCC crystal structure, so the packing should be equally efficient...
Hi guys,
I am trying to produce a desktop feature for a client which consists of a 3d printed cube with a metal ball at its center. I can suspend the ball in the center of the cube using a support or piece of rod, but I would really like to try and make it levitate using an electromagnet. I...
I have an 80 ft metal tower that is cemented into a dirt ground. It houses two small antennas to send and receive signals for wifi. This tower's power source is not a home. It has a dedicated line that runs directly to its own power meter. This tower is about 300 ft from a concrete home. The...
Homework Statement
I want to build a musical instrument for homework . I want to cut triangular metal plate where triangle will stand vertical to ground , bottom of triangle is 1 inch wide and clamped , triangle height is 42 inches.
Does that triangle produce different notes when hitting from...
Good morning everyone, new member. Have been reading some other posts for awhile. I am auto technician/business owner. I was wondering if I was to post some rudimentary plans for a rv cover I am going to build over a 2 post outdoor car lift, if some one would be willing to give me points on any...
Okay, I will give a quick run down of what I am trying to do here. What I want to do is build a tesla turbine from old hard drive disks. Being that they're already rated for high RPM, it seems like a viable option. Now these disks are probably going to be aluminum and I am probably going to buy...
I haven't been able to find much information on the thermal decomposition of metal oxides into their corresponding metals and oxygen. What temperature would Fe3O4 decompose mostly(80%) into its base elements? Additionally, how can this information be determined based upon bond...
Homework Statement
The susceptibility of a simple metal has a contribution ##\chi_{c.c}## from the conduction electrons and a contribution ##\chi_{ion}## from the diamagnetic response of the closed-shell core electrons.
Taking the conduction electron susceptibility to be given by the free...
Which metal platings on glass will provide 100% reflection as a mirror?
In which case we will get an brighter image than the actual one in mirror?And in which case it will be darker?Which metal(used for platings) will absorb a very little amount of ray? Can anyone give the explanation?
Homework Statement
A punch is used for cutting an (approximately) circular hole with a diameter of 35 mm through a metal sheet 0.2 cm thick. If the shear strength of the metal is 80 MPa, estimate the force needed to punch the hole. Make it clear how you have calculated this value.
Homework...
Homework Statement
The figure shows a metal coil labored as A. Heading torwards a region where a uniform static magnet field exists, poiting torwards the ground (hence X). The coil moves with the same constant velocity. As it enter the magnet field the coil will have an induced current in it...
Homework Statement
If a metal is adhered to a surface of another metal, let's say copper is plated onto aluminum, how can the elastic modulus of copper can be extracted given only the data of the thickness of the copper and aluminum, the young's modulus of the combined metal and the modulus of...
Hello Physics Forums!
My problem is as follows. I have a device that produces heat via Nichrome coils. I want to heat another small piece of metal (in this case stainless steel) with those Nichrome coils. I need to reach 175 degrees C, and so far I haven't found a readily available thermal...
Arrange the energy released upon hydration of Magnesium Oxide,calcium oxide,barium oxide,strontium oxide.
I placed Magnesium oxide at the last,since magnesium hydroxide is a stable so lot of energy must be released in order to achieve that state,but the answer says calcium oxide.
To elaborate more on my question: Is it possible to send metal balls through a pipe with magnets arranged a certain way which could hit a target with force. I've seen something similar done before but I think the ball was also a magnet, is that the only way possible?
I would like to know the sheet resistance of a metal mesh that consists of 3 larger busbars (W=0.0025 cm L=0.3 cm) and 10 smaller fingers (W= 0.0002 cm L= 0,16416 cm) which are all connected by a big collection bar. The thickness of the whole layer is 0.00. This collection bar has been...
Homework Statement
I need to identify which class bar 1 and bar 2 belong in based on observed attraction/repulsion. Then I need to determine if the end of 2A would attract, repel, or niether to end 3A.
EDIT: Could not get this image in the post due to security reason apparently so here is the...
Homework Statement
X and Y are two uncharged metal spheres on insulating stands, and are in contact with each other. A positively charged rod R is brought close to X. Sphere Y is then physically moved away from X. What are the final charge states of X and Y?
Homework Equations
N/A
The...
Hi,
Can anyone help me in finding out a Diamagnetic or Paramagnetism or Ferromagnetism or any other metal which has following capabilities:
1- Should not be attractive towards magnet.
2- Should not allow magnetic fields to pass through inside.
Thanks!
THG
Hello.
I'm using CT (Current Transformer) to measure the current flowing on the power line. The frequency of the current is 13.56 MHz. CT appeared to be metal-shielded (This metal case of CT may be grounded when CT is used).
CT has a toroidal shape and the power line under the measurement...
Hi all,
I have a question about charging a meta plate or a piece of metal with a capacitor. I need to charge a plate to negative or positive and search for some methods. I know charging by Conduction, Friction and Induction. I would like to use another method. I want to charge a capacitor (E.g...
Homework Statement
A metallic sphere is charged. Where will the charges go?
At center or on surface or uniformly distributed.
Homework Equations
I think it should be uniformly distributed. Cause that's why we have terms like volume charge density like we do q/volume.
The Attempt at a Solution...
Homework Statement
A uniform metal pole of height ##30.0m## and a mass ##100kg## is initially standing upright but then falls over one side without its lower end sliding or losing contact with the ground.What is the linear speed of the pole's upper end just before impact ?
Homework...
Homework Statement
A total charge of 21 μC is applied to a thin, 1μm square metal plate 72 cm on a side.
Find the electric field strength near the plate's surface, far from the edges.
Homework Equations
I think E = kq/r^2, but I really don't know.
The Attempt at a Solution
I am...
Homework Statement
Two large metal plates of area 1.1 m^2 face each other, 6.2 cm apart, with equal charge magnitudes but opposite signs. The field magnitude E between them (neglect fringing) is 50 N/C. Find |q|.Homework Equations
|q|=σA
E=σ/(2Eo)⇒σ=2EoE
|q|=2EoEA
The Attempt at a Solution
I...
Homework Statement
A metal ring with a radius of 10cm and resistance 0.1Ω passes through a delimited magnetic field, look at the photo posted below. The ring has a velocity of 5m/s, and the magnetic field has the field strength 0.4T. When the ring passes through the magnetic field, at some...
I need the ionic radius of the cation in the following anhydrous salts:
FeCl2 and CoCl2
Looking at this database: http://www.knowledgedoor.com/2/elements_handbook/shannon-prewitt_effective_ionic_radius_part_2.html
Knowing that the coordination number of both Fe2+ and Co2+ cations is 6, I am...
Homework Statement
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I had an inorganic lab this week which involved making VO(acac)2 from VOSO4⋅xH2O. In order to calculate the percentage yield, I need to work out x, that is, the number of water molecules coordinated with the vanadyl sulfate n-hydrate before the reaction. I'm stuck...