In 1862, at the Battle of Shiloh in Tennessee, hundreds of wounded men fell and were unable to get up. Due to the raging battle and a lack of medical resources, many suffered for days on the wet, cold, muddy ground. And as they lay there (presumably in agony), some of them noticed that their wounds began to glow a faint greenish blue.
Once the soldiers were gathered and carted to an army hospital the mystery grew – the men who had noticed the faint light (since dubbed Angel’s Glow) turned out to be far more likely to recover than the men whose wounds did not flash green in the darkness.
The mystery of Angel’s Glow remained until 2001, when 17-year-old Civil War buff Bill Martin visited the Shiloh battlefield with his mom. There they learned about the legend of Angel’s Glow, and his mom, a microbiologist, commented that the soil bacterium she studied, Photorhabdus luminescens, is bioluminescent – meaning it gives off its own light.
Upon learning that the bacteria’s glow is blue, her son wondered whether it may have been the source of the mysterious Angel’s Glow. His mom encouraged Bill and his friend Jonathan Curtis to tackle the question for their school’s science fair.
As they investigated, they were temporarily stumped when they learned that the human body temperature is too high to host the glowing bacteria, but, after learning that the soldiers’ spending days on the cold ground with little or no protection would have lowered their body temperatures, they forged ahead.
The boys learned that the P. luminescens bacteria lives inside tiny, parasitic worms called nematodes that burrow into insect larvae in the soil, where they then vomit up the glowing bacteria. The vomit releases chemicals that kill not only the larvae, but any other microorganisms living inside them.
And with that, the boys solved the mystery. They figured that the men, lying on the cold ground, got contaminated soil in their wounds. The nematodes vomited the glowing bacteria, which killed the other (more harmful) bacteria infecting the open woulds. The glowing bacteria was working as an antibiotic, the reason these soldiers were so much more likely to survive.
Pretty cool science project, if you ask me. Much better than the baking soda volcano thing or, more popular lately, the science project about how much stress a science project causes the average family.
(h/t: Kids Discover)
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