Home science: soda battery
Learn about the charging power of soda!
Warning: only under adult supervision.
- two small glasses;
- two galvanized screws;
- two copper coins;
- crocodile clips;
- digital alarm clock.
Connect a copper coin to a galvanized screw using a crocodile clip. Put the coin in one glass, and fix the screw to the wall of a second glass. Using crocodile clips, connect another screw to the “–” terminal of a digital clock, and another coin to the “+” terminal. Put the second coin in the glass with the first screw, and fix the second screw on the wall of the glass with the first coin. When the glasses are filled with soda, the clock starts working!
Metal screws are often coated with zinc to prevent them from reacting with substances from their environment (for example, oxygen and water) via a phenomenon known as corrosion. Such screws are said to be “galvanized.” Meanwhile, soda contains what is known as acidity regulators, often either citric or phosphoric acid. These substances make the acidity of the drink suitable for our bodies. When the circuit is closed, these acidity regulators react with zinc and copper, electric current begins to flow through the circuit, and the clock starts working! The galvanized screws can be replaced with another metal, such as iron, but this will diminish the voltage of the “battery” as iron is less chemically active than zinc. You can confirm this by comparing the positions of zinc and iron in the electrochemical series.
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