The heat engines namely steam engine and Internal Combustion engine solved travel and transportation problems of mankind. From depending on manual human labour and animal power- which came with a number of limitations, to portable engines that could drive the wheels without being tiered for hours and for miles; the jump was significant. The society started progressing in leaps and bounds. Raw material could reach factories faster and finished products could reach markets faster. Agriculture produces could reach to consumers faster.
But human endeavour to understand nature and natural forces did not end here. Man continued to find laws that governed nature based on natural phenomenon. These laws inspired inventors to build machine that put these laws to use for making the human lives easier and far more enriching. One such discovery that changed the course of human civilization forever was ELECTRICITY.
Humans were introduced to electricity by electric eel and such aquatic creatures. However, this introduction was hardly productive. The next big milestone came when humans discovered Static Electricity. Rubbing of certain materials on certain other materials made the material charged and it could attract lighter objects like feathers. The first record of this phenomenon is available since as early as 600 BCE. But this phenomenon was not well understood and could not be put to use to any human use.
In 17th and 18th century, more experiments were done on static electricity. Benjamin Franklin is credited to discovery of electricity. He used a kite and key to experiment in 1752. His experiment showed that the lightening is the same as electricity. This was a crucial understanding to see electricity in action in natural phenomenon. After all, science uses naturally occurring events as a step stone to develop its understanding, to mimic the event and put it to human use.
However, all these discoveries and experiments of static electricity were giving power in a sudden burst which was not possible to contain or put to any use. (In fact, to this day we wish to harness the power of lightening. It could solve all our power problems.) So, it was a milestone achievement when Italian physicist Alessandro Volta discovered that certain chemical reactions could also generate electricity. If one could control the rate of the chemical reaction, one could ensure a steady supply of electricity.
This discovery was that chemical reactions could generate electricity was quite a chance discovery. Around 1800, an Italian doctor Luigi Galvani found that a frog’s leg twitched when it touched two different kinds of metals. Volta studied these findings and concluded that the different metals created a potential difference and thus the electric current flowed. So, Volta needed only to create a potential difference between two points which could be connected through a wire for electric current to flow. As simple as water flowing through pipe.
The Voltaic cell opened a door for chemical cells. Different metals and electrolytes have been tried by different scientists. A few that we use till date are Lead Acid cell, and Dry cells (as in pencil/AAA batteries).