What Are the Requirements for Good Conduction of Electricity?
Understanding the requirements for electrical conductivity can help you avoid making mistakes in physics or chemistry class and can also allow you to determine which items can be used to transmit an electric signal. Electricity is basically the flow of negatively charged particles, or electrons, toward a positive charge. A positive charge attracts a negative charge in the same way the north pole of a magnet is attracted to the south pole of another magnet. Most electronic conductors are metals because of their atomic structure, but nonmetals can also be conductors.
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Free Electrons
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Most metals are good conductors of electricity, and this is a result of the structure of metals at an atomic level. All atoms are made up of positively charged protons and neutral neutrons, which are contained within the atom’s nucleus. Negatively charged electrons orbit the nucleus like planets around the sun. In a metal, there are many electrons. The ones closes to the nucleus are held tightly, but the ones farther away move around freely. This is why metals are good conductors of both heat and electricity. When a negatively charged electric signal made up of electrons reaches the free electrons in the metal, it causes a domino effect of repulsion (two matching charges repelling each other), which leads to an electric current.
Ions
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Common table salt dissolved in water creates an electric conductor, because the ions within it are free to roam around in the water and be affected by the charge. Ions are electrically charged atoms or groups of atoms. The chemical name for table salt is sodium chloride; it is made up of positive sodium ions and negative chloride ions. These ions, though stuck in place when salt is crystallized, can move around when salt is dissolved in water. This allows the positive sodium ions and negative chloride ions to all congregate together in exclusive groups when an electric current is introduced. The negative cathode attracts the positive ions and the positive anode attracts the negative ions. This flow of electrically charged particles makes salt water conduct electricity.
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Low Resistance
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If you imagine an electric current as the flow of water through a hose, resistance is like the friction on the sides of the hose which slows the water down. Different hose materials would create more or less friction and thereby affect the flow of the current. Similarly, different materials hold varying degrees of resistance to electric current. For example, silver has a very low resistance, and wood has a very high resistance. The level of resistance, measured in “ohms,” measures how well a material can conduct electricity.
Superconductors
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Some materials which do not ordinarily conduct electricity can become much better conductors if cooled to drastically low temperatures. The material has to be cooled to near absolute zero (-273 degrees Celsius) for this process to work, and it only works with some substances. Essentially, super-cooled materials often lose all resistance to electricity. This obviously causes an increase in electrical conductivity and could even lead to conductors with 100 percent efficiency.
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References
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