what is a logarithmic
A logarithm is the power to which a number must be raised in order to get some other number (see Section 3 of this Math Review for more about exponents). This is an example of a base-ten logarithm. We call it a base ten logarithm because ten is the number that is raised to a power. The base unit is the number being raised to a power. There are logarithms using different base units. If you wanted, you could use two as a base unit. For instance, the base two logarithm of eight is three, because two raised to the power of three equals eight: