Examples of Electrical Conductivity
We explain the examples of electrical conductivity. The electrical conductivity is the physical property by which a material is capable of transporting an electrical current through it . It occurs to a greater extent in transition metals and in aqueous solutions of ionic substances, because there are electrons available in them that can help the movement of charges.
Units of conductivity
Electrical conductivity is represented by the Greek letter sigma σ, and it is unique for each substance according to its chemical constitution. The units that are handled are the Siemens each meter (S / m). Sometimes actually measured values are generally very small, so their submultiples are used, such as:
- MicroSiemens / centimeter (mS / cm), which equals 1 * 10 -6 Siemens every centimeter.
- MilliSiemens / centimeter (ms / cm), which is equal to 1 * 10 -3 Siemens every centimeter. electrical conductivity
Electrical conductivity in substances
All matter that has electrical conductivity is called an electrical conductor . The flow of electrical energy through a conductor is due to the transport of electrons . Depending on how this transport is carried out, this material can be of two types:
- Metallic or electronic conductor
- Ionic or electrolytic conductor electrical conductivity
A metallic or electronic conductor is a metal whose internal structure has electrons arranged to transport a charge. The transition metals meet this characteristic, so are suitable: the best conductors are gold, silver and copper. Due to its economy, copper is the most widely used for electrical installations; it is transformed into thin wires and covered with an insulator to make electricity available to humanity.
The ionic or electrolytic conductors are mixtures of water with an ionic compound, ie, aqueous solutions such as salt water table. In them, the conductivity depends directly on the concentration of dissolved solids , therefore, the higher the concentration, the higher the conductivity. If in that case more salt is added to the water, the conductivity of the mixture will be higher.
Conductivity in solutions is also affected by temperature . When the mixture is cold, below room temperature (20 ° C to 25 ° C), the particles are more ordered and the ions will be accessible for the electric current to travel thanks to them. On the other hand, if the solution is hot, its particles will be agitated and will obstruct the flow of the current. It is not only about connecting a source such as a battery, but also regulating the temperature.
How is electrical conductivity measured?
There are specialized devices for measuring electrical conductivity called conductivity meters . The conductivity meters have a sensor, a panel and a digital display that will show the value of conductivity in a substance, especially in aqueous solutions. examples of electrical conductivity
- The sensor is tubular in shape and has a membrane at its tip. The latter will come into contact with the aqueous solution and will detect the concentration to relate it to a conductivity value. If several measurements are made, it is always essential to wash the body of the sensor with distilled water, so that each time it starts from a “blank” and the measurement is authentic. examples of electrical conductivity
- The board offers keys for power, calibration options, change of units (μS / cm to mS / cm), among other more specific commands such as transferring data to a USB memory.
- The digital display will show the conductivity reading in the units that are set before starting. Since the measurement takes time to stabilize, you will have to wait a few seconds and shake the solution a little so that the membrane assimilates the concentration that is present. The value in the reading will fluctuate until it remains fixed. electrical conductivity
Examples of electrical conductivity
- Distilled water: 0.5 μS / cm
- Domestic water: between 500 and 800 μS / cm
- Sea water: 56 mS / cm or 56,000 μS / cm
- Deionized water: 5.5 * 10 -6 S / m
- Maximum value for drinking water: 1,055 mS / cm or 1,055,000 μS / cm. electrical conductivity
- Copper: 59.6 * 10 6 S / m
- Graphene: 98.7 * 10 6 S / m
- Silver: 63 * 10 6 S / m
- Gold: 45.5 * 10 6 S / m
- Iron: 15.6 * 10 6 S / m
- Nickel: 14.3 * 10 6 S / m
- Aluminum: 37.8 * 10 6 S / m
- Tungsten: 18.2 * 10 6 S / m
- Palladium: 9.5 * 10 6 S / m
- Zirconium: 2.36 * 10 6 S / m
- Carbon: 2.80 * 10 4 S / m
- Silicon: 1.60 * 10 -5 S / m
- Germanium: 0.0220 S / m
- Quartz: 1.33 * 10 -18 S / m
- Paraffin: 3.37 * 10 -17 S / m