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Particulate

Particulates are very tiny pieces of a solid or liquid that are carried floating in a gas. When the tiny pieces are solid, it is called a smoke. When the tiny pieces are liquid, it is called an aerosol. Aerosols can be naturally found in clouds a ...

                                               

Pasithee (moon)

Pasithee or Jupiter XXXVIII, is a non-spherical moon of Jupiter. It was found by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the designation S/2001 J 6. Pasithee is about 2 kilometres in diamete ...

                                               

Peaking power plant

A peaking power plant is a power station that only runs during peak hours of demand of electricity. Because of that, the price of electricity it generates is generally higher than the electricity generated by base load power plant, which operates ...

                                               

Pearl

Pearls are made of a kind of material made by mollusks, like oysters. Pearls are small and often white but sometimes in pale colors or even black. They are often round, but sometimes half-round, oval, or in different shapes. Pearls are often used ...

                                               

Pebble

A pebble is a piece of rock with a particle size of 4 to 64 millimetres. They are often made of flint. Pebbles are larger than granules 2 to 4 millimetres diameter and smaller than cobbles 64 to 256 millimetres diameter. A rock made predominantly ...

                                               

Pedogenesis

Pedogenesis or soil evolution is the process by which soil is formed. Climate regulates soil formation. Soils are more developed in areas with higher rainfall and more warmth. The rate of chemical weathering increases by 2-3 times when the temper ...

                                               

Perdita (moon)

Perdita is a closer moon to Uranus. Perditas discovery was not simple. The first pictures of Perdita were taken by the Voyager 2 spacecraft in 1986, but it was not seen on the photographs for more than ten years. In 1999, the moon was noticed and ...

                                               

Peridot

Peridot is the gem quality version of the mineral olivine. The name of the gemstone is believed to come from either the Arabic word faridat meaning "gem" or the French word peritot meaning "unclear." Peridot is one of the few gemstones that comes ...

                                               

Perseus Arm

The Perseus Arm is one of two major spiral arms of the Milky Way galaxy. The second major arm is called the Scutum–Centaurus Arm. The Milky Way is a barred spiral galaxy with two major arms and a number of minor arms or spurs. The Perseus Spiral ...

                                               

Persistent organic pollutant

Persistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. For this reason, they persist in the environment for a long time. They can be transported ...

                                               

Pest control

Pest control is group of methods to control some species of animals and plants that are considered by humans as harmful to their health, economy or ecology. Pest control is as old as agriculture, as there has always been a need to keep crops free ...

                                               

Petrified wood

Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of per mineralization. All the organic materials have been replaced ...

                                               

Phase change

A phase change is a change in the states of matter. For example, a solid may become a liquid. This phase change is called melting. When a solid changes into a gas, it is called sublimation. When a gas changes into a liquid, it is called condensat ...

                                               

Phonology

Phonology is part of linguistics. Linguistics is the scientific study of language. Phonology is the science that studies the way that sounds carry meaning in language. Sounds that carry meaning in language are called phonemes. Sounds that do not ...

                                               

Phosphor

The chemical element is called Phosphorus in English A phosphor is a chemical compound that emits light when it is exposed to light of a different wavelength. Phosphors do not contain the chemical element Phosphorus, which can be made to glow a d ...

                                               

Pigment

A pigment is something that is added to something else to give it color. Natural pigments can come from just about anything. Pigments can be made from animals, plants, rocks and minerals or even the ground itself, for example clay plus salts. Pig ...

                                               

Piltdown Man

Piltdown Man was once thought to be a "missing link" between man and ape. The first Piltdown fragments were discovered in 1912. Thereafter, over 500 scientific essays were written on the Piltdown Man in a 40-year period. The discovery was proven ...

                                               

Planetarium

A planetarium is a theater built to show educational and entertaining presentations about astronomy and the night sky. They are also used for training in celestial navigation. A main part of most planetariums is the large dome-shaped screen onto ...

                                               

Plate boundary

The major types of plate boundaries are: Collision boundaries. These collide, forming a subduction zone West coast of the Americas or a continental collision India with Asia. Mountains orogeny, valleys, volcanoes. Transform or fault boundaries. H ...

                                               

Pleiades

The Pleiades are a group of stars in the night sky. You can see them in the constellation Taurus, the bull. Charles Messier gave it the name M45. They are named after the Pleiades in Greek mythology. This an open star cluster of middle-aged hot B ...

                                               

Pōhutukawa

The pōhutukawa, also known as the New Zealand Christmas tree, New Zealand Christmas bush, and iron tree, is a tree native to New Zealand. It grows mainly on the coast of the North Island. It is evergreen and has bright red flowers. These flowers ...

                                               

Polar vortex

The polar vortex is a persistent large-scale cyclone located near geographical poles of a planet. On Earth, a polar vortex is usually in the middle and upper troposphere and stratosphere. The cyclone surrounds the polar highs. Polar storms lie in ...

                                               

Pollutant

Pollutants are compounds which are dangerous to the environment. They can also be harmful to humans in the long-term range. They come from mineral and fossil sources or are produced by humans themselves. Many pollutants have a poisonous effect on ...

                                               

Polyp (medicine)

A polyp is a growth of tissue in areas such as the colon, stomach, nose and ear. It has a stalk which attaches the growth. If it doesnt have a stalk then it is called sessile.

                                               

Population pyramid

A population pyramid is a graph. It has two back-to-back bars. These bars show the population in groups of ages, with woman in one side and man in the other side. The pyramids show the age distribution of the place, which can help in understandin ...

                                               

Portia (moon)

Portia is a closer moon to Uranus. It was found from the images taken by Voyager 2 on 1986-01-03, and was given the designation S/1986 U 1. The moon is named after Portia, the heroine of William Shakespeares play The Merchant of Venice. It is als ...

                                               

Positron

A positron is the antimatter version of an electron. It has the same mass and spin as an electron. However, it has a positive electric charge, whereas an electron has a negative charge. Like all antimatter, when it meets its so-called counterpart ...

                                               

Pound-force

The pound-force, or simply pound, is a unit of force. The pound-force is about equal to the gravitational force applied on a mass of one pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements. ...

                                               

Power cut

A power cut, sometimes called a power outage or blackout, is a word for when the electric power does not work in an area. It is sometimes caused by a power line falling down, but may also happen due to routine maintenance. In poor countries, such ...

                                               

Power transmission

Power transmission is moving energy from where it is made to where it is used. Power is defined formally as units of energy per unit time. In SI units: 1 watt = 1 joule/s = 1 newton * metre/second 1W=1J/s=1N m/s.

                                               

Prairie restoration

Prairie restoration is a type of habitat conservation, for prairies and habitats that lived alongside prairies. It is the act of restoring land that was once native prairie to how it once was. In North America this is usually defined as pre-settl ...

                                               

Praxidike (moon)

Praxidike or Jupiter XXVII, is a non-spherical moon of Jupiter. It was found by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000, and given the designation S/2000 J 7. Praxidike orbits Jupiter at an average dis ...

                                               

Precambrian

Pre-cambrian is a term used to describe the eons before the Cambrian. It lasted from about 4.567 billion years ago to about 542 million years ago. It starts with the beginning of the Earth, about 4.567 billion years ago. When it ends, there were ...

                                               

Prime Meridian

The Prime Meridian is the meridian that goes through the Royal Observatory, Greenwich in London it is also known as the International Meridian or Greenwich Meridian. Other longitudes are given as east or west of the Prime Meridian. Lines like thi ...

                                               

Proactivity

In behavioural psychology, proactivity is thinking ahead. It means doing things before they are needed. It also means preventing something before it happens. It means the same thing as anticipation. The term is often used in organizational behavi ...

                                               

Process (computing)

In computing, a process is an instance of a computer program that is being sequentially executed by a computer system that has the ability to run several computer programs concurrently. A computer program itself is just a passive collection of in ...

                                               

Progesterone

Progesterone is a steroid hormone. In animals, it is made from cholesterol. It is the base for making certain estrogens and androgens. In animals, it is produced by their body mainly during the second half of the menstrual cycle. During pregnancy ...

                                               

Prospero (moon)

Prospero is a small retrograde non-spherical moon of Uranus found on 1999-07-18 by the astrophysicist Matthew Holman and his team, and given designation S/1999 U 3. Confirmed as Uranus XVIII it was named after the sorcerer Prospero in William Sha ...

                                               

Proton

A proton is part of an atom. They are found in the nucleus of an atom along with neutrons. The periodic table groups atoms according to how many protons they have. A single atom of hydrogen is made up of an electron moving around a proton. Most o ...

                                               

Protostar

Protostar is an early stage in the evolution of a star that usually grows to the point of beginning nuclear fusion and becoming a star by gathering mass. It is made of a contracting cloud of cold and dark interstellar medium. Protostars has lower ...

                                               

PSR B1257+12 B

PSR B1257+12 B is an extrasolar planet in the constellation of Virgo. It is around 980 light years away from Earth. It was the first planet ever discovered outside of the Solar System. It is over four times bigger than Earth. It orbits the pulsar ...

                                               

Psychiatric hospital

A psychiatric hospital is a place where mentally ill people are kept so they can be treated. Doctors who work at psychiatric hospitals are called psychiatrists. Usually people choose to be in a psychiatric hospital. Sometimes psychiatrists can pu ...

                                               

Puck (moon)

Puck is a closer moon to Uranus. Puck was found from the images taken by Voyager 2 on December 30, 1985, and was given the designation S/1985 U 1. In Celtic mythology and English folklore, a Puck is a mischievous sprite, imagined as an evil demon ...

                                               

Puddle

A puddle is a small mass of liquid, usually water, uncontained on a surface. It can form either in depressions in the surface, or directly upon the flat surface, held together by surface tension. A puddle is generally considered to be small enoug ...

                                               

Pumice

Pumice is a term for a lightweight volcanic rock. It is a solidified frothy lava, created when highly-heated, pressured molten rock is shot out from a volcano. Its light weight is due to air spaces, which are caused by fast cooling and loss of pr ...

                                               

Quart

A quart is a unit of measurement for volume. It is a quarter of a gallon or two pints. Because the imperial system and the American system use different gallons their quarts are different too.

                                               

Quartzite

Quartzite is a hard metamorphic rock. It is formed when sandstone is squeezed and heated under a chain of mountains. Although pure quartzite is white, it usually occurs in shades of pink and red. This happens when it contains some iron oxide Fe 2 ...

                                               

Radioactive waste

Radioactive waste is a term used for certain substances that are radioactive and that are no longer useful. Most radioactive waste is a by-product of operating nuclear power plants. Certain treatments in hospitals use radioactive substances. Scie ...

                                               

Rankine scale

The Rankine scale is a thermodynamic temperature scale. It is based around absolute zero. Rankine is similar to the Kelvin scale in that it starts at absolute zero and 0 °Ra is the same as 0 K but is different as a change of 1 °Ra is the same as ...

                                               

Raven paradox

The Raven paradox is a paradox first presented by the German logician Carl Gustav Hempel in the 1940s. The paradox stems from two intuitive principles for inductive reasoning: logically-equivalent claims are interchangeable and particular instanc ...

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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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