By Isaiah David Updated Mar 24, 2022

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Electricity and Conductivity

To understand why salt water conducts electricity, we first need to define electricity. Electricity is the flow of charged particles—primarily electrons—through a medium. In metals such as copper, electrons move freely, carrying current directly. In electrolytes like salt water, current is transported by ions.

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Dissolving Salt in Water

Pure water is a poor conductor; only a minuscule amount of current can pass through it. When sodium chloride (NaCl) dissolves in water, the molecules dissociate into sodium (Na⁺) and chloride (Cl⁻) ions. The Na⁺ ion, having lost an electron, carries a positive charge, while the Cl⁻ ion, having gained an electron, carries a negative charge.

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Generating a Current in Salt Water

Applying an electric source creates two terminals: a negative (cathode) and a positive (anode). Opposite charges attract, so Na⁺ ions are drawn toward the cathode and Cl⁻ ions toward the anode. These ions shuttle electrons between the terminals, forming a continuous conductive pathway that allows a measurable current to flow.

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