Numerous materials (like copper) and liquids (like water) can conduct electricity. However, impurities can lower this ability to keep electricity moving, which creates resistance. Fewer impurities mean lowered resistance (measured in ohms) and raised conductivity rates (measured in mhos for solids or micro-mhos for liquids). To increase their conductivity, fluids can have nutrients added and metals can be bonded with other metals (as alloys), while resistance-producing impurities are removed.
The significance of conductivity in water: Micro-mhos (µmhos/cm) are the basic measurement for conductivity for liquids. The conductivity range for distilled water is 0.5 to 3 µmhos/centimeter. U.S. rivers conductivity range from 50 to 7,500 µmhos/centimeter, and industrial waters can go up to 10,000 µmhos/centimeter. In the case of bodies of water, conductivity measures water quality, or pollution levels. Distilled water's conductivity is so low that it's considered an insulator. If minerals and metals are suspended in it, ions form. These can be measured as conductivity.
Features of copper conductivity: Copper is a great thermal (heat) conductor, it resists corrosion, and it's better at conducting electricity than any other metal with the exception of silver. Electricity flows freely through copper wires with little energy loss. Substantial strips or rods of copper ground buildings against lightning by conducting its electricity to the ground. Copper atoms are densely clustered, allowing electrons to move between them freely. Copper atoms are one electron short, making them positive ions.
Conductivity is measured with a meter that sends voltage through two electrodes submerged in the liquid or attached to the substance being tested. The voltage measurement is translated to mhos or micro-mhos per centimeter, and the answer is displayed. In the case of rivers and lakes, conductivity readings are usually obtained in the field and returned to the lab for evaluation. Determining the correct conductivity reading depends on the type of water (fresh, salt or distilled) or the metal/alloy, geography and other mitigating factors (weather or human influences, for example).
Conductivity and insolation in solid substances is important for electrical purposes. Electricity will only flow through materials that have conductivity (e.g. copper, silver and aluminum), making them best for wiring buildings and appliances. Using metals with lower resistance and higher conductivity means less power loss during transmission. Insulators (e.g. glass, wood and rubber), on the other hand, will not conduct electricity and are effective for coating conductors and preventing conductors from touching each other, which could cause an accidental short circuit between wires.
Conductivity of water is important because it reveals water's salinity and the concentration of other minerals and contaminants. Environmentalists can use conductivity to track the movement of water systems in order to predict and solve problems with marine life. Conductivity tests demonstrate the connection between soil conditions and drought, heavy rain, and other environmental conditions that could affect farming and crop yield. It takes the guess work out of whether to irrigate or fertilize.
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- Specific Conductivity. "Our Lake." September 2009.
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