Can water be electrified? The interaction between water and electricity is complex, largely depending on its purity. While pure water is a poor conductor, dissolved substances transform it into a medium through which electricity can readily flow. This distinction is important for both scientific understanding and safety.
Water’s Electrical Conductivity
Pure water is a poor conductor of electricity. Water molecules are covalently bonded and do not easily dissociate into free ions, which are necessary for carrying an electric charge. In this form, there are very few mobile charged particles available to transport an electrical current. Pure water acts more like an insulator than a conductor.
Most water encountered in daily life, however, is not pure. Tap water, pond water, and seawater contain various dissolved impurities like salts, minerals, acids, and bases. These impurities dissociate into positively charged ions (cations) and negatively charged ions (anions) when dissolved. For instance, common table salt (NaCl) dissolves into sodium ions (Na⁺) and chloride ions (Cl⁻).
These free-moving ions act as charge carriers, allowing electricity to flow through the water. The more dissolved ionic substances present, the higher its electrical conductivity. This is why saltwater, with its high concentration of dissolved ions, is a strong conductor.
The Dangers of Electricity in Water
The conductive nature of impure water presents safety concerns. Since most water in homes and outdoor environments contains dissolved impurities, it can become a dangerous pathway for electricity. When an electrical current contacts water, such as from a faulty appliance or power line, the water can become electrified. This creates a risk of electric shock for anyone in or near the water.
The human body is largely composed of water and contains dissolved salts, making it a conductor of electricity. If a person comes into contact with electrified water, the current can pass through their body. This can cause severe muscle contractions, paralysis, burns, organ damage, or cardiac arrest. Even a low-level voltage can cause muscle paralysis, leading to drowning, sometimes termed electric shock drowning (ESD).
To mitigate these dangers, several safety measures are important. Keep electrical devices and outlets away from water sources in kitchens and bathrooms. Do not handle appliances with wet hands, and ensure electrical cords are in good condition and away from hot or wet surfaces. Ground-Fault Circuit Interrupters (GFCIs) quickly shut off power if a ground fault is detected, significantly reducing shock risk in wet environments like bathrooms and swimming pools.
Electrolysis: Using Electricity to Transform Water
Beyond simply conducting electricity, water can undergo a chemical transformation through electrolysis. This process uses an electric current to break down water molecules (H₂O) into their constituent elements: hydrogen gas (H₂) and oxygen gas (O₂). Electrolysis involves passing a direct electric current through water, often with an added electrolyte to enhance conductivity, as pure water is not sufficiently conductive for efficient electrolysis.
During electrolysis, water molecules are split at two electrodes. At the cathode (negative electrode), hydrogen gas is produced, and at the anode (positive electrode), oxygen gas is generated. This chemical change is distinct from water merely allowing electricity to pass through it; electricity actively causes the water’s chemical bonds to break.
Electrolysis has various practical applications. It is a method for producing hydrogen, which can serve as a clean fuel source. This process is also used in industrial settings, such as generating oxygen for the International Space Station or in chemical manufacturing. Electrolysis demonstrates how electricity can not only travel through water but also fundamentally alter its chemical composition.