The First Battery
The famous Italian scientist Luigi Galvani, while studying the anatomy of a frog, accidentally discovered that when the dissected frog’s muscles were touched with a charged (with static electricity) metal, it would agitate the frog and make its ligaments twitch. Another renowned Italian scientist Allesandro Volta was quick to understand the principle acting behind the above phenomena. He realized that there was something inside the frog’s flesh which reacted with electricity to produce the twitching effect. He was able to successfully reverse the process and, in fact, produce electricity.
It wasn’t hard for him to find out that the frog’s flesh, which acted like an electrolytic chemical when brought in contact with two different metals, could generate electricity. He further went on with his research and in 1800 made the first electricity producing battery using two dissimilar metals (zinc and silver) immersed in an electrolyte consisting of sulphuric acid.
His experiment may be understood as follows:
The electrolyte sulphuric acid used is present as 2H+ and SO42-.
The negatively charged sulphate ions (SO42- ) react with the zinc plate or electrode and the hydrogen ions react with the silver electrode producing a potential difference across them.
- When the two electrodes are connected externally, the circuit becomes completed to initiate the flow of electrons and constitutes the generation of electricity.
- Hydrogen gas is released during the process as a byproduct.
The following chemical reactions are involved in the process:
Zn → Zn2+ + 2e-
2H+ + 2e- → H2
From the above discussion, the idea becomes pretty simple to understand: by inserting two dissimilar metals into a chemical substance, electricity can be generated.