From electric eels to execution chairs, the story of electricity involves more than just one or two electric shocks.
So how do scientists harness this mysterious power of nature?
We think of electricity as man-made and modern things. But, in fact, it exists in all of us creatures, and only by discovering a fish capable of attacking us with a voltage of 600 volts can we learn how to artificially produce it.
This creature is called the electric eel, which is native to the Amazon River. This giant marine animal (technically a fish, often mistaken for an eel) consumes enough electricity to make a horse writhe painfully.
Its body contains three organs made up of electrolytes, or "batteries," arranged in a row so that ionic currents can flow through and stacked up to increase energy. Its biology proved so vital to human understanding of electricity that the inventors of the battery copied its structure.
There are very few animals that generate electricity, mostly fish. Distributed in tropical Africa and the Nile, this electric catfish can emit a voltage of 350 volts. Electric rays or torpedo fish can produce a voltage of about 220 volts, which was recorded by the ancient Greeks and nicknamed "hemp fish" because it was used as a basic anesthetic in early medicine.
Other animals use electricity to help them locate their prey or navigate dark waters. Sharks are excellent at electrical reception, which is why they are such excellent predators. If your muscles emit electric sparks (and if you're alive, they do), sharks will find you.
Most animals that feel electricity are aquatic animals. But there are a limited number of electric mammals, such as the terrestrial echidna (sometimes referred to as the spiny anteaters) and their close relatives, platypus, which live both in the water and on land.
Both echidnas and platypus have tiny electrical receptors on their noses (up to 40,000 platypuses) that can detect current and allow them to dig holes in silt or dryland, close their eyes and locate their prey. On land, the power capacity of the echidna is more pronounced. More recently, a species of dolphin has also been discovered, and the Guyana dolphin (also technically a mammal) also uses electricity reception.
On dry land, bees flap their wings at such a fast rate that they generate an electric charge, which is then transferred to the flowers as they pollinate. Thus, another bee can detect the presence of an electric charge when visiting the same flower and tell them not to forage there.
Jack Ashby, manager of the Grant Zoological Museum at University College London, said: "It is possible that many aquatic animals, possibly other mammals, use electricity in ways that we do not know or document. ”。“ Because humans don't do that, we don't pay enough attention to it. ”
Our focus on electric eels proves that the impact it can unleash is staggering. In their native South America, electric eels have been known for generations, and some early experiments began in the 18th century. But in Europe and North America, they resemble mythical animals, such as unicorns.
More broadly, at the time, electricity was seen as a phenomenon. Humans in the Middle Ages and renaissance saw events such as lightning as something magical, invisible, mysterious, such as magic or the wrath of God.
New shocks
When naturalists first heard about electric eels in the mid-18th century, when Benjamin Franklin was experimenting with lightning rods, the discovery sparked curiosity in the scientific community.
"These eels were sent to North America and London, where they became part of the whole scientific spectacle that was being built at the time," said Ruth Garde, curator of the new exhibition "Electricity: The Spark of Life" for the Wellcome Collection. "They were put on display in the theater and were called the wonders and wonders of electricity. People spend huge sums of money watching them. ”
In those days, the term "electrician" was used to describe scientists who were interested in electrical experiments. As part of their investigation, the electricians collected charges from Leiden jars (literally glass jars lined with metal), which occasionally caused them severe electric shocks. Scientists are working to prove the existence of atmospheric electricity.
Studies of an animal proved that this animal could produce more voltage at will than humans stored in a jar, which helped a lot to improve their understanding.
Around 1800, the Prussian naturalist Alexander von Humboldt published the earliest (and most notable) report of the arrival of electric eels in Europe. He visited what was then Dutch Guiana, the area between the Orinoco and Amazon rivers in South America, and described seeing electric eels release such high voltages that locals feared they were monsters.
Humboldt described a "picturesque scene" in which fishermen herded their horses into swamps and were startled by eels so that once their electricity was released, they could be safely collected for study and experimentation.
"Some of these horses were injured or killed, and local fishermen left them in the swamp ... It's a pretty scary story, but [Humboldt's] description of it is very convincing," Gard said.
Fierce competition
But the arrival of electric eels in the U.S. and Europe is not just the region's biggest electrical event Gard said: "Electric eels are critical to our understanding of how to develop current for our own use. ”
Alessandro Volta, an Italian physicist who invented the battery (or volt stack) and named the potential unit after it, based his work on the dissection of electric eels.
Walter called his earliest devices "organs" — referring directly to their biological roots," Gard said. In fact, the invention of the battery was an unexpected but pleasing result of Volta's research on the controversial animal electricity of the time. He had criticized the experiment of the Italian physician Luigi Galvani in the 1780s, in which he connected the nerves of a dead frog to a metal wire and pointed it to the sky during a thunderstorm. The frog's legs twitched. "As if it were still alive.
As Volta and Galvani debated whether electricity came from biological or external sources, Mary Shelley was intrigued by the idea of sparks resurrecting the dead in some way, which inspired her to write Frankenstein.
Galvani later conclusively demonstrated the presence of electricity in animals. But his work did not succeed in convincing Walter that he opposed the concept on religious grounds. Marco Piccolino, co-author of "The Shocking History of Electric Fish," said Galvani's theory was largely ignored by the scientific community until his experiments were revived decades later.
Modern science holds that all muscle cells, whether human or animal, have potentials. Two centuries of experiments have shown that muscle contractions are caused by electrical impulses in nerves and that potential electrical energy is present on all cell membranes. Why are some animals more electrically charged than others? The evolution over millions of years of certain muscle cells into electrical cells that produce higher voltages than ordinary muscle cells seems to be an evolutionary quirk.
Gard said: "Electric eels help us understand what electricity is. "This makes us realize that electricity is in our bodies, how it works through our bodies, and how it helps it through the body." ”
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Article source: BBC EARTH, Matilda Battersby