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Who discovered air pressure?

Air pressure is the weight and force of air pressing down on the earth. Air pressure constantly changes due to weather systems and altitude. Low air pressure usually signals stormy weather, while high air pressure typically means clear skies and calm weather. Using a barometer to measure air pressure helps meteorologists accurately predict the weather.

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What causes fluctuation in line voltage?

Additionally, existing electrical infrastructure commonly deals with increasing electrical demands, which it is not always able to accommodate. Poor power generation and distribution is the result. Symptoms of voltage fluctuation include flickering or dimming lights, computer crashes, motor tripping, cooking problems, equipment stalling and even electrical shocks. The lifespan of light bulbs is also a common indicator, as light bulbs do not last as long under poor power distribution.

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Why is phosphorus trichloride polar?

Phosphorus trichloride has a pyramidal structure, with the phosphorus atom in the center. Chlorine is very electronegative and pulls electrons closer to it. The lone pair of electrons, however, doesn't pull electrons toward itself; in fact, it repels them. The net result is a movement of electron density away from the lone pair, which creates a center of positive charge. Conversely, the area between the three chlorine atoms becomes a center of negative charge, making the atom polar.

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What are some different types of transformers?

Power transformers are used in electric power transmissions and electrical appliances to convert main voltage to low voltage. There are two types of power transformers: laminated core and toroidal transformers. Laminated core transformers have an insulated lamination that minimizes eddy current loss in the inner core. Toroidal transformers have a lower external field and take up less space than the laminated core transformers.\nPotential transformers are used to monitor single-phase and three-phase power line voltages in power metering applications. There are three types of potential transform..

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How many cubic liters are in a liter?

One can convert between liters and cubic units where the units are measurements of length. For example, 1 milliliter, or 1/1,000 of a liter, is equivalent to 1 cubic centimeter; therefore, 1 liter is equal to 1,000 cubic centimeters. One liter is also equivalent to 1 cubic decimeter. One cubic meter is equal to 1 kiloliter, or 1,000 liters; similarly, 1 liter is equivalent to 1/1,000 of a cubic meter.

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What does the phrase "grass erosion dam" mean?

While the application and forms can vary, erosion dams are an essential part of any construction project. This is especially true with very damp areas or construction taking place on a slope. With road construction, the risk of the roadway being undercut by water run off is very real. The danger results from a loss of structural stability which occurs when too much of the supporting soil becomes stripped from beneath the asphalt, eventually causing the shoulder of the road to fail and collapse. Any disturbed earth presents a similar problem, whether from recent utility work or other constructi..

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What is a Faraday box, also known as a Faraday cage?

The Faraday cage was invented by Michael Faraday, an English scientist who discovered many fundamental concepts of electromagnetism. Faraday's first "cage" was an entire room lined with metal foil. While this may seem similar in execution to the notorious tinfoil hat, tinfoil hats are actually ineffective at blocking electromagnetism because they are not fully enclosed. As hats, they are open at the bottom, and they actually serve to conduct electromagnetism into the body and amplify it. The ideal Faraday cage is a solid piece and contains no openings; however, mesh enclosures can also sh..

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What are highland climate regions?

The difference between climates at high altitudes in comparison to lower altitudes occurs for several reasons. As altitude increases, temperatures and pressure falls. Levels of dust and overhead air also decrease, which allows for greater atmospheric transparency. Precipitation also increases with altitude, and orientation of mountain slopes may influence climate as well.

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What are the different types of clay?

These categories of clay are based on how long and at what temperature the clay must be fired in order to reach maturation, or its optimal hardness. Each category includes clays with different colors and degrees of workability. Clay colors are caused by impurities. For instance, red clay generally contains a high level of iron relative to other clays, and black clay contains manganese. Clay workability refers to how plastic the clay is. Higher levels of kaolin make clays less plastic, but also less porous.\nPorcelain clays have the highest firing temperature. They are made of fine-grained whit..

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What does stone mean in terms of weight?

Historically, the stone was a local weight standard that varied widely between different locations. The weight was frequently set based on a stone that had been chosen for use in weighing different goods. The stone stood for anywhere between 3 and 40 pounds, depending on the location. In Britain, a stone of different commodities stood for different weights. For example, a stone of wool was 14 pounds, but a stone of mutton was only 8 pounds.

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