Dimensional Analysis. Dimensional Analysis (also called Factor-Label Method or the Unit Factor Method) is a problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. It is a useful technique.
In 1887, the first dry cell battery was invented. Unlike previous batteries, it used a paste electrolyte instead of a liquid.
The Baghdad Battery Believed to be the first battery, about 2000 years old from the Parthian period. The jar was found just outside Baghdad and is composed of a clay jar with a stopper made of asphalt. Sticking through the asphalt is an iron rod surrounded by a copper cylinder.