Battery of lemon
The lemon battery experiment is proposed as a project in many science textbooks. Involves inserting in a lemon, two objects made of different metals,for example a galvanized nail and a copper coin. These two objects function as electrodes, causing an electrochemical reaction mediated lemon juice that generates a smallamount of electric current.
The aim of this experiment is to show students how batteries work. After the battery is assembled, you can use a multimeter to check the voltagegenerated, which usually does not exceed 1 V. The voltage and current produced is insufficient to ignite a standard LED, would be required for a battery made of severalstacks of lemon. It takes at least two cells connected in series to double the number of voltage and connected in parallel to achieve currents of 5 mA.
Technically occuroxidation and reduction.
At the anode, zinc (zinc) is oxidized:
Zn → Zn2 + - 2 e-
At the cathode, the copper is reduced:
Cu + + + 2e-→ Cu
A common alternative to lemons aresometimes apples or potatoes. Any fruit or vegetable containing acid or another electrolyte may be used, but the lemons are preferred due to their higher acidity. Othercombinations of metals (as magnesium and copper) are more efficient, but are usually used zinc and copper that are reasonably safe and easy to obtain.
Use a strip of magnesiuminstead of zinc must duplicate about the current produced in the cell of lemon (approximately 240 uA with zinc and about 400 uA with magnesium) and also slightly increases thevoltage (0.97 V and 1.6 V with zinc with magnesium). The voltages and currents reached critically depend on the acidity of the lemons and the size and metal objects used.
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