Does electricity travel faster through tap, lake, or sea water?
November 16, 2010
I'm working on an adv. science class project so I need to know, does electricity travel through chlorinated, tap, lake, or sea water faster?Sierra C [last name deleted for privacy by Editor]
6th grader - Forks, Washington, U.S.A
November 16, 2010
Hi, Sierra. You are young to be considering such a question, but the actual answer is that electricity travels faster through hot water than cold and through turbulent water than still, but the amount of salt or chlorine doesn't much effect the speed of the electricity moving through the water. But electricity travels much easier, and with less resistance, and a greater current will flow through salt water.
The explanation is that electricity moves through water by means of small particles called "ions" that physically migrate through the water from one electrical pole to the other. For example, salt is sodium chloride, the chemical formula is NaCl. When you put salt into water it dissolves and separates into Na and Cl halves called ions. The Na ions are positively charged, that is, they have one more proton than electron. The Cl ions are negatively charged, that is, they have one more electron than proton. The positively charged Na ions migrate toward the negative pole because electrical opposites attract, and the negatively charged Cl ions migrate toward the positive pole for the same reason. In this way extra electrons or extra protons move from one pole to the other, effectively making an electric current.
Heat is actually a measure of electrons "vibrating" and that pushing and shoving speeds up the travel of the ions; movement of the water as a whole also speeds up the movement.
If there is very little salt dissolved in the water, there are very few ions available to transport these charges, so not much current flows. It takes billions of electrons to make a barely measurable flow of current. If the water is very salty, there are plenty of these "charge carriers" available, so the current flow is high. Chlorinating the water also provides Cl ions to transport charges, but realistically the amount of chlorine, and Cl ions from chlorinating drinking water is quite minimal.
Ted Mooney, P.E. RET
Pine Beach, New Jersey