The first theoretical description of metals was given by Paul Drude in 1900 with the Drude model, which explained electrical and thermal properties by describing a metal as an ideal gas of then-newly discovered electrons.

The sea of electrons in metallic bonds causes the characteristically good electrical and thermal conductivity of metals, and also their " shiny " reflection of most frequencies of white light.

Other objects on which frost tends to form are those with low specific heat or high thermal emissivity, such as blackened metals ; hence the accumulation of frost on the heads of rusty nails.

All metals and alloys eventually melt or decompose, and there is significant researching into ceramic materials that can be made with greater thermal stability and desirable structural properties.

Chemical resemblances between the two metals include the formation of a nitride by reaction with N < sub > 2 </ sub >, the formation of an oxide () and peroxide () when burnt in O < sub > 2 </ sub >, salts with similar solubilities, and thermal instability of the carbonates and nitrides.

The electrical and thermal conductivity of metals originate from the fact that their outer electrons are delocalized.

It has one of the lowest coefficients of thermal expansion among commercially used metals.

Metallic bonding accounts for many physical properties of metals, such as strength, malleability, ductility, thermal and electrical conductivity, opacity, and luster.

The advent of X-ray diffraction and thermal analysis made it possible to study the structure of crystalline solids, including metals and their alloys, and the construction of phase diagrams became accessible.

In strong conductors ( metals ) electrons are so degenerate that they can not even contribute much to the thermal capacity of a metal.

Among metals, pure silver has the highest thermal conductivity ( the nonmetal carbon in the form of diamond and superfluid helium II are higher ) and one of the highest optical reflectivities.

This means that for liquid metals the thickness of the thermal boundary layer is much bigger than the velocity boundary layer.

The effect of temperature on thermal conductivity is different for metals and nonmetals.

Following Wiedemann – Franz law thermal conductivity of metals is approximately proportional to the absolute temperature ( in Kelvin ) times electrical conductivity.

In pure metals the electrical resistivity often increases proportional to temperature and thus thermal conductivity stays approximately constant.

copper, timber, iron ore, nitrates, precious metals, molybdenum, hydropower, thermal power, nutrient-rich ocean currents

This is due to the way that metals are chemically bonded: metallic bonds ( as opposed to covalent or ionic bonds ) have free-moving electrons which are able to transfer thermal energy rapidly through the metal.

Electrons also conduct electric current through conductive solids, and the thermal and electrical conductivities of most metals have about the same ratio.

By assuming that the material contains immobile positive ions and an " electron gas " of classical, non-interacting electrons, the Drude model was able to explain electrical and thermal conductivity and the Hall effect in metals, although it greatly overestimated the electronic heat capacity.

The low hardness of copper partly explains its high electrical ( 59. 6 × 10 < sup > 6 </ sup > S / m ) and thus also high thermal conductivity, which are the second highest among pure metals at room temperature.

This is because the resistivity to electron transport in metals at room temperature mostly originates from scattering of electrons on thermal vibrations of the lattice, which are relatively weak for a soft metal.

Petit also designed a special thermometer ( using weights ) to determine the thermal dilatation coefficients of several metals.

For instance the sea of electrons causes most metals to act both as electrical and thermal conductors.

Production of many metals ( cast iron, grey iron, ductile iron, compacted graphite iron, 3000 series aluminium alloys, copper alloys, silver, and complex steels ) are aided by a production technique also referred to as thermal analysis.

It has a few characteristic properties: high density, softness, ductility and malleability, poor electrical conductivity compared to other metals, high resistance to corrosion, and ability to react with organic chemicals.

Some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades ( like aluminium, magnesium, some steels, and titanium ).

The electrical conductivity, as well as the electrons ' contribution to the heat capacity and heat conductivity of metals can be calculated from the free electron model, which does not take the detailed structure of the ion lattice into account.

Chemically, the precious metals are less reactive than most elements, have high luster and high electrical conductivity.

The metals are held together by metallic bonding, which confers distinctive physical properties such as their shiny metallic lustre, ductility and malleability, and electrical conductivity.

Researchers currently are exploring ways of " doping " organic semiconductors, like melanin, with relatively small amounts of conductive metals to boost conductivity.

Radar signals are reflected especially well by materials of considerable electrical conductivity — especially by most metals, by seawater, by wet land, and by wetlands.

It has the highest electrical conductivity of all metals, even higher than copper, but its greater cost has prevented it from being widely used in place of copper for electrical purposes.

Degenerately ( very highly ) doped semiconductors have conductivity levels comparable to metals and are often used in modern integrated circuits as a replacement for metal.

The loss of most transmission lines are dominated by the metal loss, which causes a frequency dependency due to finite conductivity of metals, and the skin effect inside a conductor.

The quantization of conductivity is more pronounced in semiconductors like Si or GaAs than in metals, due to their lower electron density and lower effective mass.

In metals conductivity is primarily due to free electrons.

Blondlot, Augustin Charpentier, Arsène d ' Arsonval and approximately 120 other scientists in 300 published articles claimed to be able to detect N-rays emanating from most substances, including the human body with the peculiar exceptions that they were not emitted by green wood and by some treated metals.

Because of the low availability relative to demand, rhenium is among the most expensive of metals, with an average price of approximately US $ 4, 575 per kilogram ( US $ 142. 30 per troy ounce ) as of August 2011 ; it is also of critical strategic military importance, for its use in high performance military jet and rocket engines.

This process, known as smelting, was first applied to metals with lower melting points, such as tin, which melts at approximately and copper, which melts at approximately.

These tombs, which date to the Early Dynastic IIIa period ( approximately in the 25th or 24th century BC ), contained immense amounts of luxury items made out of precious metals, and semi-precious stones all of which would have had to been imported from long distances ( Iran, Afghanistan, India, Asia Minor, the Persian Gulf ).

Both systems agree on the Roman numerals, which indicate ( approximately ) the highest oxidation number of the elements in that group ( and therefore indicates similar chemistry with other elements with the same Roman numeral ), which proceeds in a linearly increasing fashion for the most part, once on the left of the table, and once on the right ( see List of oxidation states of the elements ), with some irregularities in the transition metals.

The value of the composition metals in a £ 1 coin amount to approximately 4. 18 UK pence or 6. 44 US cents as of 7 January 2012.

In metals and ceramics, requirements for it being superplastic include a fine grain size ( less than approximately 20 micrometres ) and a fine dispersion of thermally stable particles which act to pin the grain boundaries and maintain the fine grain structure at the high temperatures required for superplastic deformation.

Major projects for the 1986-90 period included a 5, 600-kilometer natural-gas pipeline from the Yamburg Peninsula ( in northern Siberia ) to Eastern Europe ; the Krivoy Rog ( in the Ukraine ), a mining and enrichment combine that would produce 13 million tons of iron ore annually ; the production and exchange of 500 million rubles ' worth ( approximately US $ 650 million ) of equipment for nuclear power plants ; and joint projects for extracting coal in Poland, magnesite in Czechoslovakia, nickel in Cuba, and nonferrous metals in Mongolia.

Compacting pressures range from to for most metals and approximately to for non-metals.

As a rule of thumb, the effects of creep deformation generally become noticeable at approximately 30 % of the melting point ( as measured on a thermodynamic temperature scale such as kelvin or rankine ) for metals and 40 – 50 % of melting point for ceramics.

This included approximately 138 tons of cardboard, 43 tons of metals, 28 tons of paper, 26 tons of plastics and 1, 776 lbs of computer waste.

When dissolved in an approximately 35 % nitric acid solution it is called Schwerter's solution and is used to test for the presence of various metals, notably for determination of silver purity.

The Company has self-funded approximately $ 1. 8 billion in capital investments between 2004 and 2009 and now believes it has world's newest and most advanced processing paths for its specialty metals, particularly for titanium and titanium alloys, nickel-based alloys and superalloys, zirconium and hafnium, and other specialty alloys.

This empirical law is named after Gustav Wiedemann and Rudolph Franz, who in 1853 reported that κ / σ has approximately the same value for different metals at the same temperature.

At the melting point of some metals the ratio can be approximately 0. 1 %.

A soldering gun is an approximately pistol-shaped tool for soldering metals using tin-based solder to achieve a strong mechanical bond with good electrical contact.

A modern ferrocerium firesteel product is composed of an alloy of rare earth metals called mischmetal ( containing approximately 50 % cerium, 25 % lanthanum, and small amounts of praseodymium and neodymium ), plus iron and a small amount of magnesium:

In the first phase ( 2005 – 2007 ), the EU ETS included some 12, 000 installations, representing approximately 40 % of EU CO < sub > 2 </ sub > emissions, covering energy activities ( combustion installations with a rated thermal input exceeding 20 MW, mineral oil refineries, coke ovens ), production and processing of ferrous metals, mineral industry ( cement clinker, glass and ceramic bricks ) and pulp, paper and board activities.

The chemicals included in the patch test kit are the offenders in approximately 85-90 percent of contact allergic eczema and include chemicals present in metals ( e. g. nickel ), rubber, leather, hair dyes, formaldehyde, lanolin, fragrance, preservative and other additives.