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Every cell you meet in a chemistry chapter carries two names. NCERT's Class 12 electrochemistry chapter describes the zinc-copper Daniell cell, with a potential of 1.1 V, and says "such a device is called a galvanic or a voltaic cell." The two names belong to two Italian scientists who disagreed sharply about where electricity in a frog's leg came from. Their argument produced the first battery.
What did Galvani see in his frog experiments?
Luigi Galvani (1737–1798) was a physician and professor of anatomy in Bologna. According to the Museo Galileo's biography, he observed that freshly removed frog legs contracted in response to lightning or sparks from an electrostatic machine, and also when touched with a metal arc. As an anatomist, he was convinced the cause was an electricity specific to living things, which he called animal electricity. He set out the theory in *De viribus electricitatis in motu musculari commentarius* (Bologna, 1791).
In Galvani's picture, the metal only provided a path. The electricity was already in the frog.
Why did Volta disagree?
Alessandro Volta (1745–1827), born in Como, held the chair of experimental physics at the University of Pavia from 1778, according to the Museo Galileo's biography of Volta. The Royal Society of London awarded him the Copley Medal in 1794.
Volta accepted that some fish, such as the torpedo, have special electric organs. He did not accept that ordinary animal tissue made electricity. As a 2013 paper in the Journal of the History of the Neurosciences summarises, he thought Galvani's frog experiments were flawed by the use of metals. His claim was that two different metals in contact, with something moist between them, were enough to drive electricity. The frog's leg was just a very sensitive detector.
This is a disagreement you can test. If Volta was right, you should be able to make electricity with no animal at all.
How did Volta build the first battery?
Volta described the answer in a letter to Sir Joseph Banks, President of the Royal Society, written in French and dated Como, 20 March 1800. It was read on 26 June 1800 and printed in the Philosophical Transactions under the title "On the electricity excited by the mere contact of conducting substances of different kinds". The title is his argument.
In the letter's text, Volta describes 30, 40, 60 or more pieces of copper, or better silver, each against a piece of tin, or better zinc, with an equal number of layers of water, or a better conductor such as salt water, or pieces of card or leather soaked in it. Stacked in repeating order, metal, metal, wet card, the pile gave shocks like weakly charged Leyden jars. The difference was that it never needed charging and kept working each time it was touched. Volta compared it to the natural electric organ of the torpedo and the electric eel.
The Museo Galileo notes that the pile was the first generator of a continuous current, unlike the instant discharge of an electrostatic machine. Volta demonstrated the research in Paris in 1801 before Napoleon, who later made him a count.
Worked example: why stack the cells?
Volta's pile worked because the voltages of the cells add when they are in series. Take a modern zinc-copper cell with emf 1.1 V, the value NCERT gives for the Daniell cell.
Question. Twenty such cells are connected in series. Each has an internal resistance of 0.2 Ω. They drive a 7 Ω lamp. Find the current and the voltage across the lamp.
Total emf = 20 × 1.1 = 22 V.
Total internal resistance = 20 × 0.2 = 4 Ω.
Current I = 22 ÷ (7 + 4) = 2 A.
Voltage across the lamp = I × R = 2 × 7 = 14 V. Check: lost inside the cells = 2 × 4 = 8 V, and 14 + 8 = 22 V.
The JEE (Main) 2026 syllabus lists "internal resistance, potential difference and emf of a cell, a combination of cells in series and parallel", so this is exam material. A common mistake is to forget the internal resistances add up too, which is why a tall pile was never as strong as its total emf suggests. Our post on Kirchhoff's laws and common circuit mistakes covers harder cases.
So who was right?
Both, in different ways. Volta was right that two dissimilar metals with an electrolyte make a source of current: that is every galvanic cell in your chemistry book. Galvani was right that living tissue is electrical. In a 1998 review in Brain Research Bulletin, the physiologist Marco Piccolino argues that two centuries of research showed how insightful Galvani's idea of animal electricity was, and that he founded electrophysiology, the science behind nerve impulses and the ECG.
The Museo Galileo's summary is similar: Volta's theories prevailed in his time, but Galvani deserves credit for the research that started modern electrophysiology.
What can a student take from Volta and Galvani?
Turn a disagreement into a test. Volta did not just argue. He asked what should happen if he was right, then built it.
Separate the effect from the detector. The twitching leg was real, but it did not prove where the electricity came from. In a numerical, ask the same question about which quantity is measured and which is assumed.
Expect both sides to hold part of the truth. Many textbook ideas, from light to atoms, settled this way.
If you want to see how emf, internal resistance and current trade off as you change a circuit, the Fermi Simulation Lab has interactive simulations for ideas easier to see than read. For electrode potentials, read our post on electrochemistry and the Nernst equation.
Try it now: work out the lamp voltage again with 30 cells instead of 20.
