Chapter 5. Project: Water Conductivity/Numerical Output

The conductivity meter is probably the simplest environmental meter in this book. Its workings rely upon the fact that pure water does not actually carry an electric charge very well. So what we’re really doing with this device is assessing the concentration of conductive particles that are floating in the (mostly nonconductive) water.

What Is Conductivity, and Why Do I Care?

Water is very seldom just the sum of its basic chemical formula: two atoms of hydrogen and one of oxygen. Typically, water is a mixture that also includes other substances that have dissolved into it, including minerals, metals, and salts. In chemistry, water is the solvent, the other substances the solutes, and combined they make a solution.

Solutes create ions: atoms that carry an electric charge. These ions are what actually move electricity through water.

That’s why measuring conductivity is a good way to learn how pure (really, how impure) a water sample may be: the more stuff that’s dissolved in the watery solution, the faster electricity will move through it.

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