In the Clarendon Laboratory at Oxford University, a bell has been ringing for at least 175 years. It’s powered by a single battery that was installed back in 1840. Researchers don’t know exactly what the battery is made of. The reason for that is, they are too afraid that opening the bell would ruin the experiment.
According to the university, the Oxford bell has rung roughly 10 billion times. After more than 175 years of battery life, the voltage left in the battery is so low that the human ear can’t actually hear it ringing. In each oscillation, the bell uses 1 nanoAmp current.
What is known about the battery
The brass bells are charged by two dry piles covered in sulfur with discs of silver, zinc and a paste inside. This set-up keeps the minimum amount of moist for the electrolyte to work. In 1840, the voltage produced was about 2000 volts. Between the bells hanging by a silk thread is a small brass ball. The ball is charged by one bell and then repelled to the other. When it touches the other bell, it changes polarity and then again… repelled. This process creates what is called the “ever ringing bell”, and when looking closely, it is actually possible to see the vibrations.
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Longest battery life in the world
Oxford University suggests that the bell may actually have been set up as early as 1825. The bell’s power source holds the Guinness World Records for the “world’s most durable battery.”