an Al Gore Rhythm is when Al Gore tries to dance..

but seriously, an algorithm allows a person to keep using the result of an approximation to be fed back into the system again and again until a certain accuracy is achieved.. it will not be the exact answer but it is good enough...
algorithms were used in the past to predict the phases of the moon, the tides, the locations of the stars and all that in order to be used in navigation where the sailor needs only an approximation of where he is and where his destination is to a certain degree of accuracy, and everything else can be done by eye...
in today's terms, we can use algorithms for calculations where there are no fixed formulae and can be fed into a computer to be looped until a very accurate approximation of the answer is found...