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Kimberlite

Kimberlite is an igneous rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa. The discovery of a big 83.5-carat diamond in 1871 started a "diamond rush". This resulted in the Big Hole, a larg ...

Ophiolite

An ophiolite is a section of the Earths oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level. The rocks which make up ophiolites are an altered form of basalt. The rocks are often green. They are found ...

Palisades Sill

The Palisades Sill is a Triassic intrusion, formed 200 million years ago. It runs through parts of New York and New Jersey. It is noteworthy for The Palisades, cliffs which rise steeply above the western bank of the Hudson River. The visibility o ...

Sill (geology)

In geology, a sill is a flat sheet-like intrusion. As molten magma, it pushed between older layers of rock. The older rock may be sedimentary rock, beds of volcanic lava or tuff, or metamorphic rock. The sill does not cut across preexisting rocks ...

Tuff

Tuff is a type of rock produced by the eruption of volcanoes. It consists of consolidated volcanic ash ejected from vents during a volcanic eruption. Rock with more than 50% tuff is called tuffaceous. The chemical and mineral composition of tuff ...

Xenolith

A xenolith is a rock fragment which another rock surrounds. It happens most in igneous rock when magma is fluid enough to flow round more solid rock. Xenoliths may be covered in the margins of a magma chamber, torn loose from the walls of a flow ...

Gneiss

Gneiss is a type of metamorphic rock. The minerals in gneiss may come from rocks which were originally either igneous or sedimentary. They were heated and squeezed, and the minerals recrystallized. Orthogneiss is gneiss got from igneous rock such ...

Greenstone belt

Greenstone belts are large regions of very ancient metamorphosed volcanic rocks. The name comes from the green colour of the minerals in the rocks. Chlorite, actinolite and other green amphiboles are the typical green minerals. Greenstone belts w ...

Millook

Millook is a place on the north coast of Cornwall. It has these remarkable cliffs. The cliffs at Millook are so famous they were voted by the Geological Society as one of Britains top 10 geological sites. They came top of the "folding and faultin ...

Schist

The schists are a group of metamorphic rocks which have lamellar minerals, such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains so that a form called quartz schist is produced. By definition, sc ...

Slate

Slate is a metamorphic rock. It is formed from shale by being under pressure and moderate heat. Shale itself is formed from muddy clay, splits into thin plates. This characteristic splitting is carried over into slate. Schist is a rather similar ...

Ashford Black Marble

Ashford Black Marble is a kind of dark limestone, which was mined from Ashford-in-the-Water, in Derbyshire, England. Once cut, turned and polished, its shiny black surface becomes very beautiful. Strictly speaking, Ashford Black Marble is not a m ...

Breccia

Breccia is a type of rock formed of broken fragments of minerals or rock cemented together by a fine-grained matrix. The matrix may be similar to or different from the composition of the fragments. Rocks formed by sticking together pieces of prev ...

Clay

Clay is a fine-grained silicate mineral made when rocks break down. Wet clay is soft and can be shaped to make pottery, bricks and other things. When it is shaped and then fired in a kiln to make it hard, it becomes pottery. Clay often contains s ...

Flint

Flint, or flintstone, is a kind of sedimentary rock, made of silica. Bands of flint are found embedded in chalk and other kinds of soft limestone. When the chalk is eroded, the hard flint nodules survive as pebbles on a shingle beach. It may happ ...

Mudrock

Mudrocks make up most of the sedimentary rocks on Earth. They are a class of fine grained siliciclastic sedimentary rocks. The types of mudrocks include: siltstone, claystone, mudstone, slate, and shale. Most of the particles are less than 0.0625 ...

Peat

Peat forms when plant material, usually in marshy areas, is inhibited from decaying fully by acidic and anaerobic conditions. It is composed mainly of marshland vegetation: trees, grasses, fungi, as well as other types of organic remains, such as ...

Red beds

The term red beds usually refers to strata of reddish-colored sedimentary rocks such as sandstone, siltstone or shale that were deposited in hot climates under oxidizing conditions. They are usually formed in terrestrial situations: on land, and ...

Shale

Shale is a fine-grained sedimentary rock formed from mud. The mud is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by ...

Siltstone

A siltstone is a mudrock. For a rock to be a siltstone, it must be over fifty percent silt-sized material. Silt is any particle smaller than sand, 1 / 16th of a millimeter ~0.06 mm, and larger than clay, 1 / 256th ~0.004 mm of millimeter. Silt is ...

Matter

Matter is the substance of which all material is made. That means objects which have mass. More specifically, they must have rest mass, which is a form of energy that matter has even when it is not moving, is extremely cold, etc. Matter is a word ...

Antimatter

Antimatter is a term in particle physics. Antimatter is a material composed of antiparticles. These have the same mass as particles of ordinary matter but have opposite charge and properties, such as lepton and baryon number. Encounters between a ...

Vacuum

A vacuum is a place where there is no matter. Sound cannot move in a vacuum. Outer space is not a perfect vacuum, because there is a very small number of particles there.

Alternating current

An alternating current is an electric current of which magnitude and direction vary, unlike direct current, whose direction remains constant. This means that the direction of current flowing in a circuit is constantly being reversed back and fort ...

Cogeneration

Cogeneration is the use of a heat engine or a power station to make both electricity and useful heat at the same time. Conventional power plants emit the heat created as a byproduct of electricity generation into the environment through cooling t ...

Direct current

Direct current is the flow of electricity in a single direction, from the positive to the negative terminals. The direct current always flow in the same direction, distinguishing it from the alternating current AC. Direct current used to be calle ...

Electric power transmission

Electric power transmission is the transmitting of electricity to places where it will be used. Specifically, it is the bulk transfer of electrical power from the power plant to substations near populated areas. Electric power distribution is the ...

Electrical circuit

An electrical circuit is a path in which electrons from a voltage or current source flow. The point where those electrons enter an electrical circuit is called the "source" of electrons. The point where the electrons leave an electrical circuit i ...

Electrical energy

Electrical energy can refer to several closely related things. It can mean: The energy provided by electricity. The energy stored in an electric field. The potential energy of a charged particle in an electric field. In any of these cases, the SI ...

Electrical filament

An incandescent light bulb has a small thin wire with two bigger wires holding it up. This wire is called a filament. The filament is the part of the light bulb that produces light. Filaments in incandescent light bulbs are made of tungsten. When ...

Electricity generation

Making electricity in one central place became useful when electric power distribution was possible. This required power transformers which could change voltage. Electricity could be sent as alternating current along electric power lines for grea ...

High-voltage direct current

A high-voltage direct current is a transmission system which uses direct electric current to transmit electricity. It is more efficient over long distances than the usual high-voltage alternating current.

Kirchhoffs circuit laws

In 1845, German physicist Gustav Kirchhoff described two laws about electrical circuits. These laws are generalizations of Ohms law. Kirchhoffs circuit laws are very useful in solving circuit problems.

Leyden jar

The Leyden jar is a device for storing static electricity. It is large glass bottle, usually lined on both the inside and the outside with some type of metal foil. Some of the early ones had water inside. They allow the experimenter to collect a ...

Lightning rod

A lightning rod or lightning conductor is an iron rod that is used to make lightning strike it, rather than strike something else. It is part of a lightning protection system. Such a system is made of many such rods. These rods are usually placed ...

Magnetic reluctance

Magnetic reluctance, or magnetic resistance, is a measurement used in the analysis of magnetic circuits. It is like resistance in an electrical circuit, but rather than dissipating magnetic energy it stores magnetic energy. As an electric field c ...

Ohms law

Ohms law says that in an electrical circuit, the current passing through a resistor is related to the voltage difference and the electrical resistance between the two sides, as long as the physical conditions and the temperature of the conductor ...

Photovoltaics

Photovoltaics are arrays of cells containing a solar photovoltaic material that converts solar radiation or energy from the sun into direct current electricity. Due to the growing demand for renewable energy sources, the manufacturing of solar ce ...

Piezoelectricity

Piezoelectric material generates a small electrical voltage, when its shape is deformed. This can be by as little as a 0.09% change, and can produce 12mAh worth of electricity at 230V. It is important to note that the actual values of a piezoelec ...

Power line

Power lines are wires that conduct electricity through to another place. Many have transformers. The voltage of the power at the end is usually 100V, 120V, or 220-240V, but is much higher while going through the electric power transmission lines. ...

Power station

A power station is a place where electricity is produced. Most do this by a big spinning electrical generator. In big powers stations the spinning is usually driven by a steam turbine. The steam may come from: Nuclear power, using radioactive sou ...

Series and parallel circuits

In a series circuit, the electrical current is only able to flow around a single path. The current will flow from a power source, such as a battery, into one or more electrical loads, such as a light bulb, and then back to the power source. In a ...

Short circuit

A short circuit is a problem in an electrical circuit where two or more wires that are not supposed to come in contact with each other touch. A short circuit can result in a very high current flowing through the circuit. The high current can dest ...

Solar panel

Solar panels get energy from the sun for people to use. There are two types of solar panels, those that collect heat, and those that produce electricity. Heat from solar panels is often used for space heating and for hot water. Solar panels colle ...

Static electricity

Static electricity means the increase of electric charge on the surface of objects. This electric charge remains on an object until it either flows into the ground, or loses its charge quickly by a discharge. Charge exchange can happen in conditi ...

Volt

For the electric plug-in hybrid concept car, see Chevrolet Volt. For the record label, see Volt Records The volt is the SI derived unit of electric potential difference or electromotive force. It is named in honor of the Italian physicist Alessan ...

Advanced Light Source

The Advanced Light Source at Lawrence Berkeley National Laboratory in Berkeley, California is a synchrotron light source. It was built from 1987 to 1993. 210 scientists and staff currently work there. The ALS is a national user facility. The ALS ...

Ferromagnetism

Ferromagnetism is a property of many materials like iron. They are magnets, so they are attracted to, or pulled towards other magnets. In physics, there are many different types of magnetism. Ferromagnetism is the strongest one. It is used every ...

Magnetic field line

A magnetic field line or magnetic flux line shows the direction of a magnets force and the strength of a magnet. The idea of lines of force was invented by Michael Faraday. His theory is that all of reality is made up of force itself. His theory ...

Meissner effect

The Meissner effect is when a magnetic field is pushed out of a superconductor when it becomes superconducting. If you were to put a superconductor in the field of a big magnet and you looked just inside the superconductor, you would see that the ...

Encyclopedic dictionary

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Pino - logical board game which is based on tactics and strategy. In general this is a remix of chess, checkers and corners. The game develops imagination, concentration, teaches how to solve tasks, plan their own actions and of course to think logically. It does not matter how much pieces you have, the main thing is how they are placement!

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