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.
Homework Statement
(Q) Calculate the center of mass of a semi-circular metal plate of uniform density ρ and thickness t. Let the radius of the plate be a. The mass of the plate is thus 1/2 (ρπat2). In your co-ordinate system, you must consider the x-axis passing through the bottom of the...
Rotational Equilibrium - Help!
Homework Statement
http://photos-a.ak.facebook.com/photos-ak-sf2p/v142/24/75/1238100168/n1238100168_30095452_8017.jpg
A uniform metal bar of mass 100 kg and length L (2.5 m) extends horizontally from a wall and connected to the wall by a pivot (F is...
Homework Statement
A hollow metal sphere has 6 cm and 10 cm inner and outer radii, respectively. The surface charge density on the inside surface is -100 nC/m^2. The surface charge density on the exterior surface is + 100 nC/m^2 .
What is the strength of the electric field at point 4 cm from...
Hi all,
It is my understanding that the color of a material results from the inability (or lesser ability) to absorb in that particular wavelength. Reading Atkins' "Physical Chemistry" (8th ed.), I run into a statement I couldn't quite get. On page 730 (chap. 20), he states the following...
Question is Why does a desk lamp often has small holes near the top of the metal lampshade. How do these holes keep the lamp cool.
This is what i think. Heat travels upward by air convection. Since air is a poor conductor, very little heat travels sideways.
That is my reason what do u...
A question about metal thermo flasks, or metal vacuum flasks if you prefer.
I understand the principle of thermo/vacuum flasks.
Just to proofed that I read up before posting this question :-)
http://en.wikipedia.org/wiki/Vacuum_flask
But today I had a look at on of those new-isch thermo...
Suppose one has a solid metal body (in static eq'm) with a cavity inside it.
Assume the cavity has no charge in it. This is how one could prove that there are no fields inside the cavity: choose two points A and B, both in the solid part of the metal body. Follow a path through the metal...
hey does anyone know how you can carry out an experiment to find out if a metal or non-metal has a metallic lustre?:confused:
i have tried looking all over the internet but i can't find anything...
if u could post answers or terms i can place into the google search panel it would be greatly...
If you drop a metal ball and a feather at the same time the ball will touch the ground before the feather, why is this? What effect is the Earth's atmosphere having on the feather? If you dropped a piece of metal in the shape of a feather it still would touch the ground before the feather and...
Homework Statement
This is a Problem 7.7 fom Griffiths Introduction to Electrodynamics (3ed)
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 page...
Hi All, my friend has a big chunk of Copper Iridium metal. It attracts all non-metals like paper, wood etc and reduces it to powder. It is not a magnet because it does not attract iron. Can someone please explain this phenomenon ? Please forgive me if I am in the wrong forum. I am totally...
We have a bunch of very strong pictures for this contest. Let's see if we can decide our favorite.
Please vote for the picture that best represents our theme, which is on metals.
1. turbo-1
2. Integral
http://home.comcast.net/~Integral50/Photo_contest/HPIM2549a.JPG
3. larkspur...
Thanks to Evo for graciously running the PF Photo Contest while I was on vacation.
Heavy Metal
Think "industrial". Your picture must have, as its main subject, something metallic, made of metals. This could be iron, steel, copper, alloys, etc. If it isn't clear, please include a brief...
I was reading there that if you wind a piece of metal wire into a coil it creates a magnetic field. Does this wire have to have current running through it? I know that a changing electric current creates a magnetic field but how does winding a piece of metal wire into a coil create magnetic flux?
Homework Statement
Ok this one is easy I just want to make sure:
A metal of mass M is in a smelter at temperature T_{o}.
How much heat does it take to melt the metal. Given: heat capacity, melting point T_{m}
Homework Equations
Q=Mc\Delta T
The Attempt at a Solution
So it would be...
I am wondering if:
1. Is it possible to design such system? I am trying to induce the Aluminium Tin, then deflect it using a positively charged metal plate.
2. If so, what is the cost needed? Let say I want to deflect the tin for about 5cm from the center, and the size of the design should...
I have a pictorial example in a book here of a solid that behaves very strangely indeed. I would have called it 'biaxial metallicity' but I have no idea what the correct term is - the material is apparently metallic in one direction but not in another - that is, appears to obey the free or...
I was reading the plasmon chapter of my solid state physics book and it says simple metals should reflect light in the visible region and transmit it in the ultraviolet, roughly speaking. (I think I read in a paper that for some metals, like Au and Cu, the threshold wavelength is in the visible...
Can microwaves melt metal? As far as I know, it can't melt a spoon no matter how long you put it in a microwave oven. Is it possible to get microwaves to melt metal?
Hi everybody
I am not so sure if this question is suitable to be in this box, but I hope it is. I know that all metals are opaque because they have lots of free electrons which absorb the energy of photons. But a polished surface of metal reflexes light other than absorbs it, especially...
I'm interested in hearing what metal bands you guys like. I like death metal so my favorites are: Kataklysm, Amon Amarth, All that Remains, and Scar Symmetry. List your bands and some vids.
here are mine:
http://youtube.com/watch?v=3rfTqmX6f3k This vid is a video of Martin Maurais (kataklysm...
I need help solving this question:
The magnetic flux through a metal ring varies with time t according to B = 3( at 3 - bt 2) Tm2, with a = 2.00 s-3 and b = 6.00 s-2. The resistance of the ring is 3.20 . Determine the current induced in the ring at t = 1.00 s.
I know that you have to take...
This is a good one.
We all know that in an ideal gas, there is no isothermal potential energy stored when you do work on the gas. Compress the gas: all the work appears as heat, and when you cool to ambient, it's all gone. Compressed ideal gas stores no work EXCEPT as heat.
Now, less well...
can anyone help me interpret what exactly this question is asking as i am quite unawares
By direct substitution into the heat equation and calculation of boundary values,
verify that the solution u(x, t) for a metal rod of length L which satisfies
the initial temperature u(x, 0) = f(x) and...
http://www.spikedhumor.com/articles/80802/Crazy_Liquid_Metal_Material_Shows_Extreme_Elasticity_Features.html
This is one of the most interest compounds I've ever seen. Its elasticity is hard to believe even when you see it with your own eyes. The link shows a 90 second video clip of the...
Homework Statement
A hollow metal sphere has inner radius a and outer radius b. The hollow sphere has charge +2Q. A point charge +Q sits at the center of the hollow sphere.
Determine the magnitude of the electric field in the region r < a.
Determine the magnitude of the electric field in the...
How to change the melting point of a metal?
Like example:
Iron melting point: 1535 °C
Sulfur melting point: 115.36 °C
If you combine Iron and Sulfur in a airtight container and light a monster fire under it, you get a sort of a pyrite (iron disulfide (FeS2)– Melting point 1,177-1,188 °C...
Steel is a metal alloy whose major component is iron, with carbon content between 0.02% and 1.7% by weight
Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another
Stainless steel has a minimum of 10%...
In textbooks they normally emphasis the fact that when metals and nonmetals bond, the nonmetal takes away an electron from the metal resulting in ionic bonding betwen the two.
But metal and nonmetal can still result in covalent bonding when the electronegativities between the two are similar...
A metal container, which has a mass of 9.0 kg contains 17.6 kg of water. A 2.0-kg piece of the same metal, initially at a temperature of 200.0°C, is dropped into the water. The container and the water initially have a temperature of 15.1°C and the final temperature of the entire system is...
I have what is hopefully a quick question. Using only an unmarked magnetic bar and an identical metal bar, suggest a way to find out which is the magnet and which is the metal bar. This is supposed to be in a room with nothing but these two materials. Any help is greatly appreciated!
Can i get some help with this problem?
This problem deals with the basic loop configuration you will use in the laboratory to construct a metal detector. Two concentric circular coils of wire lie in a plane. The larger coil has 49 turns and a radius of a = 7.90 cm. The smaller coil also has 49...
A light breeze of 10mi/hr blows across a metal building. The buildings wall is 3.7m tall and 6.1m wide. A net energy flux of 347w/m^2 from the sun is absorbed by the wall and then dissipated to the air through convection. Assuming the air is 27c and 1 atm and blows across the wall as a flat...
Metal in water thermal equilibrium?? Help
Determining temperature of an oven.
Guy puts a copper bar with a mass of 5.0 kg in the oven and puts an identical bar in a well-insulated 20.0 liter vessel containing 5.00 L of liquid water and the rest saturated steam at 760 mmHg. Waits until bars...
The problem is I have two blocks on an inclined plane. They are connected by a metal rod. The bottom(2) mass provides the dominate force. Fiction is involved. They have different kinetic coefficients of friction. I need to know the acceleration of the system and the tension in the rod...
Hello everybody,
I have some problems in order to count the electrons in compound using the 18th electrons rule.
In the compound [(BuO)3 Mo Mo (OBu)3] I count 12 electrons (6 e- for Mo, 3 * 1e- for Metal-Metal bound, and 3 * 1e- for OBu). Is it correct?
In the compound W(CO)3(P...
A metal strip 7.50 cm long, 0.550 cm wide, and 0.800 mm thick moves with constant velocity v through a magnetic field B = 1.00 mT pointing perpendicular to the strip, as shown in Figure 28-35. A potential difference of 3.90 µV is measured between points x and y across the strip. Calculate the...
Ok here's my problem:
When I put a piece metal in a graduated cylinder filled with water to measure the metal's volume by "water displacement" I see air bubbles trapped under the metal. How do the air bubbles affect the density, mass and volume of the metal piece? Thanks. Need quick answer...
Why it would be unwise to almost completely fill a test tube with HCL solution before adding a piece of metal? Is it because it's a acidic solution?
Thanks
Why does my phone get a signal in a metal box??
Hi guys,
Earlier today I was telling someone about how EM radiation of low wavelength would have trouble passing through a cold plasma. I gave the example of the metal mesh in front of a microwave (as metal can be treated like a plasma)...
Dumb question...but I don't know the answer.
Is there a way to determine if a piece of metal will cause electronic interference? Is it true only for ferric metals, or can any type of metal cause transmission problems?
Cya later, alligator
Hi,
We know that when we connect the two parallel plates to a battery it will hold a +ve charge on the plate connected to positive terminal and -ve charge on the other plate. If we only connect one plate to the positive terminal, can it be charged? Isn't the positive terminal is at a...
My dishwasher in the kitchen has a metal cover inside and some persons got a small electric shock when they touched the metal cover with wet hands.
So I took a voltmeter and measured the voltage between the metal cover of the dishwasher and the metal-washbowl (I suppose the metal-washbowl is...
A metal cylinder of 55kg, (0.2m in diameter), traveling at 2.5 km/sec strikes the earth. How big a crater can it be expected to make, given average characteristics for the ground where struck?
i wanted the techinical information.
bending property of solid pipe and hollow pipe with same diameter.
which will bend more and why ?
i wanted the technical answer please help me out :smile: