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.
"Plating" Metal - Cathode or Anode?
Homework Statement
You want to plate out nickel from a nickel (II) nitrate solution onto a piece of metal inserted into the solution.
Should you use copper or zinc or can you use either of these metals?
Homework Equations
Standard Reduction...
Problem: The brass bar and the aluminum bar are each attached to an immovable wall. At 21.8 °C the air gap between the rods is 1.33 x 10-3 m. At what temperature will the gap be closed? length of brass is 2.0 meters, aluminum is 1.o meters
Why my solution isn't working I'm not entirely...
The thin metal film is scored with some pattern to 50-80% of its thickness. When exerted shear stress, the film will crack/open at score. I wonder what simple/practical techniques can be used to detect its pinhole or opening in real time?
A proton (m=1.67x10^-27 kg) that has a speed of 5.0x10^6 m/s passes through a metal film of thickness 0.010mm and emerges with a speed of 2.0x10^6 m/s. How large an average force opposed its motion through the film??
can anybody give me a clue on where i can start?
I was asked by some of my students (6th grade) why does metal heat up under pressure? For example, when you hammer a piece of metal repeatedly, it is hot to the touch.
Homework Statement
"A manufacturer of corrugated metal wants to produce metal roofing panels that are 28 in. wide and 2 in. thick by processing flat metal sheets."
the illustration shows that by "2 in. thick" they are referring to the distance between the crest and valley of the sine wave...
Hello. I manufacture a fishing alarm that is activated when 2 very small rods (each about ½ inch long and the diameter of a small paper clip) come into contact. The rods are perpendicular to each other and form an “X” shape. When the rods do touch to complete the circuit, the surface area of the...
A metal alloy consists of magnesium and aluminum.When a 1.00g sample of the alloy is reacted with excess HCl, 0.0989g of hydrogen gas forms. Calculate the percent composition of the alloy.
Ok I got the following balanced equations :
Mg + 2HCl -> MgCl2 + H2
2Al + 6Hcl -> 2AlCl3 + 3H2...
Could someone help by recommending hardware to mount a prototype board like this:
http://www.protostack.com/index.php?main_page=product_info&cPath=1_2&products_id=3
to a metal box? I was planning on drilling some holes in the metal box, then somehow mounting the prototype board(s) using...
Identifying three identical metal bars (with your eyes closed!)
Homework Statement
How would you determine, non-destructively, and with eyes closed, which is which amongst three identically-shaped metal bars known to consist of a permanent magnet, a piece of soft iron and a piece of copper...
First, there is a positive point charge sitting in space which creates an electric field around it. Then, a large metal sphere with no net charge is a added some distance to the left of it. Does the addition of this sphere change the magnitude of the electric field at some points a and b which...
I stumbled on this question while studying sound waves today, and it has got me stumped. I've been thinking this through for hours, to no avail. It goes: A park has a circular fence with a metal pipe as the top rail. If the fence is hit with a hammer it produces a sound of 350 Hz. At a point...
Is there any research done on plastic engine blocks or cannon barrels ?
I interested in using plastics at high heat high pressure environments after learning some researchers cools 1600 degree plate to 80 degrees with potassium or sodium or exotic metallic liquids.
I think it might be possible...
Three tiny charged metal balls are arranged on a straight line. The middle ball is positively charged and the two outside balls are negatively charged. The two outside balls are separated by 20 cm and the middle ball is exactly halfway in between.The absolute value of the charge on each ball is...
Metal and wood common temperature for neutral "feel"
Homework Statement
Taken from the homework: At what common temperature will a block of wood and a block of metal both feel neither hot nor cold to the touch.
Homework Equations
I believe it is just conceptual, so I do not know if one...
Hi all,
Currently I am in my internship, so I don't have any real experience in metal manufacturing.
I have a difficulty of calculating the cycle time of producing a product. The product is a waterpipe fitting. The Fitting itself has 3 different types (Straight, 90-degrees elbow, and...
hi you'al,
i hang in a knife forum and there is a lot of discussion on what steel is "best" for knife blades..latest fad/dream steel is some power made to steel from Hitachi
some of what i wander is the "powder" made no for these steels and what adds to the properties of the steel
the...
voltage/charge problem
Homework Statement
Imagine a small metal sphere left by some alien civilization is floating in space. A
probe is launched directly at the sphere in order to study it. When the probe is
1000 m from the sphere, it detects a voltage of 110.0 V; and when it’s at 100.0 m...
I'm looking to assemble two sheet metal parts (in the manner a bit like joining two halves of a box) in a simple manner that is either crimpable or some sort of snap fit. I have not seen any snap fit sheet metal designs and I wonder if there is any sort of standard practice (the aluminum sheet...
Homework Statement
One end of an insulated metal rod is maintained at 100^\circ C and the other end is maintained at 0.00 ^\circ {\rm C} by an ice–water mixture. The rod has a length of 75.0 cm and a cross-sectional area of 1.40 cm^2. The heat conducted by the rod melts a mass of 7.85 g of...
Homework Statement
A metal bar of mass m slides frictionlessly on two parallel conducting rails a distance l apart. A resistor R is connected across the rails and a uniform magnetic field B , pointing into the page , fills the entire region.
a) If the bar moves to the right at speed v, what...
What is the main reason for changing the strength of metals under very high strain rate? Do all metals show the similar trend in increased strength under high strain rate? What is the effect of crystal structure on this phenomenon?:!)
If a hot metal forging is cooled by dropping it into a pool of water, how many boundary/initial conditions do I need to solve for the temperature? I don't want to make any assumptions about temperature gradients within the forging itself (Biot number may be large, which precludes use of lumped...
Alright, I'm not really a physics major or a scientist, but I do have a basic understanding of physics. In fact, I'm actually a writer and right now I'm trying to research the physics of what this thread is titled as, a metal planet. Problem is since I'm not a physics major or scientist, I sort...
Homework Statement
A total charge Q is shared by two metal spheres of small radii R1 and R2, that are connected by a long thin wire of length L. Fin (a) the charge on each sphre and (b) the tension in the wire.
Source: Haliday 4th edn chapter 26 q. 91, p. 738
The Attempt at a Solution...
A 6.0kg metal ball moving at 4.0m/s hits a 6.0 kg ball of putty at rest and sticks to it. The two go on at 2.0 m/s.
a) How much energy does the metal ball lose in the collision?
b) How much energy does the putty ball gain in the collision?
c) What happened to the rest of the energy?
For a)...
Homework Statement
Put a hot metal ball on parallel horizontal rails. The ball starts to move. Investigate the phenomenon.
Homework Equations
I have found two equations, one exponential and one linear relating the expansion of the rails and the ball to the temperature increase...
Homework Statement
Sodium, aluminium and silver have work functions of 2.46, 4.08 and 4.73 eV respectively. Which, if any of these metals will emit photoelectrons when irradiated by Balmer-B photons from a hydrogen discharge lamp?
Homework Equations
Energy = 13.6(\frac{1}{n_{1}^{2}}...
Homework Statement
When light is frequency 2,00 x 10(in 16force) Hz prostrate a metal surface electrons are abstracted with kinetic energy 7,50 x 10(in -18force) J.
Calculate:
(a) The frequency v0 for the metal (v0: the minimum frequency of light, below which no electrons emitted).
(b)...
Homework Statement
Chromium metal, Cr(s) can be prepared from reacting chromium oxide, Cr2O3(s), with aluminum, Al(s). Al2O3(s) is a by-product. Assume a reaction of 20,0 kg of chromium oxide with 5,00 kg of aluminum metal. 1)how much Chromium metal will produced from the above reaction? 2)...
Hi all,
If i have a charged plate of charge Q coulumbs, then what is the energy contained in it?
Is the energy independent of the way in which i managed to get a single plate of Q columbs charge? In the sense , suppose in the beginning there were two plates of charge +Q, -Q columbs...
Homework Statement
Given is a metal plate with two metal bolts attached to it, the attachement is assumed to be idealy conducting. A current I flows between the two bolts. Find a general formula for the Resistance between the two bolts (depending upon: a) the thickness of the plate (delta)...
do anyone knows how to find poisson's ratio of nimonic 115 nickle based alloy?i try google it can't found it::frown:.It took me two hours for nothing..
Homework Statement
we are mixing CuSo4 (Cu2+) with an iron (Fe) powder and we are trying to determine whether Fe2+ forms or Fe3+
now the question is :
suppose that 1.0 g of iron is used in the experiment. what is the minimum volume of Cu2+ solution that must be added in order to completely...
Two small metal spheres are located 3.0 m apart. One has radius 0.48 cm and carries charge 0.15 uC. The other has radius 0.95 cm and carries charge 0.090 uC.
If the two spheres were suddenly connected by a thin wire, how much charge would move along it?
This is a question that I have been...
This is my first question in this forum. And here it is,
How do you make an insulated metal sphere has a net positive charge with a negatively charged rod?
If the rod touches the sphere, the sphere will have negative charge. If I connect sphere to ground, bring the rod near the...
Don't exactly know where to put this but how would one examine the spectra of a metal ore to find what is in it? That being, not using a mass spectrometre.
Homework Statement
A steel bar 10cm long is welded end to end to a copper bar 20cm long. Both bars are insulated perfectly on their sides. Each bar has a square cross section, 2cm on a side. The free end of the steel bar is maintained at 100 celsius and the free end of the copper bar is...
Homework Statement
Immediately outside a very long cylindrical wire of radius r1 = 1mm, the electric field is 40kV/m directed towards the wire's surface.
A hollow cylindrical metal tube with inner radius r2 = 3mm is now placed around the wire, to form a coaxial cable. What will be the charge...
. Homework Statement
A metal bar is free to slide without friction along two parallel metal rails. The circuit is completed by a battery. (conducting bars are in the x direction, left side of drawing the conducitn bars are connected by a battery, the right side is where the metal bar is) If...
Hey ... I'm trying to study for my PhD qualifying exam, and I have a bunch of questions from previous years, but no answer keys.
Homework Statement
A think uniformly charged rod of length L is positioned vertically above a large uncharged horizontal thick metal plate. The distance between...
hi, I'm a web developer so i usually stay in front of a computer for almost 12 hrs a day.
my question is, when i get up from my computer and hold a metal, ex. faucet or a spoon, or even a refrigerator holder i get electrocuted.
FYI, by the way, i got a surgical implant in my right hand...
If yes how about in comparison to water? I ask cause I was wondering how they stop the metallic fuel injection tubes from rusting out. Is there a coating or does it just not rust in presence of gasoline?
Im assuming that gasoline doesn't rust since its a hydrocarbon and water contains O, and...
hi,
everyone, now I am trying to deposite some metal layers on micro-scale cantilever surface on the purpose of bending it under the residual stress caused by metal deposition. I read some literatures which mentioned and even gave the exact value of residual stress happened in both the...