THE BIG BEAR PRECIPITATION: FUN WITH FIRE

In “The Big Bear Precipitation,” Season 9, Episode 20, our intelligent friends attempt to light a fire.“Huts they made then, and fire, and skins for clothing,

And a woman yielded to one man in wedlock . . .

. . . Common, to see the offspring they had made; The human race began to mellow then. Because of fire their shivering forms no longer

Could bear the cold beneath the covering sky.

—Titus Lucretius Carus, On the Nature of Things (50 BC)

“O for a Muse of fire, that would ascend

The brightest heaven of invention,

A kingdom for a stage, princes to act

And monarchs to behold the swelling scene!”

—William Shakespeare, Henry V (1599)

“Man may have discovered fire, but women discovered how to play with it.”

—Candace Bushnell, Sex and the City (1996)

I Am the God of Hell-Fire, and I Bring You . . . FIRE!

You remember how “The Big Bear Precipitation” goes. Sheldon and Leonard take a weekend cabin trip with Amy and Penny, but their plan to take a woodland hike is put to an end by a downpour of rain. Penny wants to light a cozy fire, and, as Sheldon and Leonard pontificate about the theories of thermodynamics, Penny turns on the gas. Instant fire, and their situation is transformed. The scene allows us to say something about the historical transformative power of fire and to reflect upon one of the most incredible scientific “inventions.”

The advent of fire isn’t exactly a machine invention, but it surely ranks up there among the greatest human innovations of all time. Predictable bores might go for obvious inventions such as the wheel, the printing press, or the Internet, while some more thoughtful souls would perhaps plump for soap, the nail, or the compass. And yet fire is simply the granddaddy of them all.

Now, the saying goes, “Have fire will travel,” so let’s go back, say, a million years. Life was hard. And nature was “red in tooth and claw,” as a famous poet once said. Your entire life was spent just struggling to stay alive. If it wasn’t the dangerous predators stalking you at night, it was the constant search for food in the day. Where would the next meal come from? When you think about it this way, the sheer potential power of fire becomes obvious. Fire would ward off the looming killer creatures, smoke out those incessantly biting insects, and help cook more food to eat. You see flames from lightning, forest fires, or even a volcano, but how do you catch and control them? Leonard and Sheldon sure know the theory, but how do you put that into practice?

Scholars believe the invention of fire was one of the main turning points in human history, but they can’t be sure exactly when fire was invented. Figuring out the invention of fire is not an easy business. When a scholar finds ancient evidence of fire, how do they tell if it was made by lightning, by a volcano, or by human hand? And even when fire seems to have been started by humans—an old hearth in a disused cave, for example—how do you tell if the fire was made from scratch, or just taken to the cave from a natural fire and kept alive as long as possible?

So, how did fire first happen? Prehistoric humans probably first captured fire by grabbing a burning stick from a wildfire and (fanning the flames to keep it alight) nourishing their newfound fire as long as possible. Can you imagine being in such a prehistoric situation? Nurturing those flames for perhaps days on end, when suddenly the fire is sadly extinguished. Stone Age humans would in such cases have been utterly reduced to a situation far worse than what Leonard and Sheldon face in “The Big Bear Precipitation.”

(Incidentally, a 2018 paper in the Journal of Ethnobiology titled “Intentional Fire-Spreading by ‘Firehawk’ Raptors in Northern Australia” described the mostly unknown behavior of “firehawk raptors,” birds that intentionally spread fire by brandishing burning sticks in their talons and beaks. According to the paper, firehawks will amass in their hundreds along burning bushfire fronts. From their border base, they will then fly into active fires, pick up smoldering sticks, and take them up to half a mile away to places the flames have not yet affected. The aim of the raptors is to spread fire to unburned locations to flush out prey via fire or smoke.)

Most scholars agree that humans had learned to control fire by about 125,000 years ago, but even earlier evidence of the control of fire ranges from 200,000 to 1.7 million years ago! There’s evidence of the use of fire from all around the world. In Beeches Pit, Suffolk, England, there are signs of fire use from 415,000 years ago. At Zhoukoudian Caves in China, there is evidence of fire as early as 230,000 to 460,000 years ago. The sign of fire at Zhoukoudian comes from burned bones, burned chipped-stone artifacts, charcoal, and ash—all alongside fossils that can be dated. And in Africa, there are signs of fire at the Kalambo Falls, in Zambia, where scholars found charred logs from about 110,000 years ago. Once humans had got a grasp of fire, so to speak, prehistoric life was totally transformed.

Fire, Food, and Chemistry

Fire is wild, and depending on where you live, it can also be quite rare. Natural fire occurs only in special places, such as close to the vent of volcanoes or near the neighborhood of natural gas. Or else fire happens on odd occasions, such as with forest or bush fires. Humans must have planned to capture fire, after they understood its power. Maybe early humans copied the behavior of birds like the firehawk raptors, but catching fire must have been quite daunting, dangerous, and tricky. Ancient myths and legends tell us that humans knew all about the danger of fire. Once they’d tamed the flames, humans first used fire for warmth and protection. But then came cooking.

Cooking got started once humans began the custom of sitting around the campfire. Some cooking is pretty basic. Roasting meat on pointy sticks is easy enough, just like a prehistoric barbeque. And you can even imagine Stone Age humans baking root vegetables in smoldering ashes. But boiling food is not so easy. At first, they heated water in leather buckets by dropping in hot stones. Quite ingenious, really. Sheldon talks about basic thermodynamics in “The Big Bear Precipitation.” Thermodynamics is the area of physics connected with the action of heat, and other forms of energy, and the relationship among them. It appears prehistoric humans had a basic grasp of thermodynamics. Later, early humans found that if you coated a basket with thick clay, it could be put on the fire and made cooking better. Later still, clay pots were used to do the cooking.

Cooking is also how humans invented basic chemistry. As clay pots could hold liquids for a longer time, humans started to spot slow chemical changes in the pots’ contents. And from this knowledge came the idea of changing materials. This is how humans learned to dip leather to toughen it, or to dunk it in dye to change its color. And all this was discovered through the invention of fire.

A good example of fire leading to the discovery of basic chemistry is the cooking of eggs. Consider the thermodynamics of the egg. An egg starts off as a pretty gloopy affair but, after heating, ends up all squidgy, especially if you hard-boil it. The gloopy-to-squidgy change is a chemical reaction in the food, as a result of fire and heat. And when scrambled, eggs take on yet another form.

Fire as Passport to Progress

Fire lit up the lives of early humans. Just think about all the historical changes that started with fire. Controlling fire meant humans could stay up at night. Those scary monsters in the dark, or the biting bugs, really don’t like fire and smoke. Fire allowed humans to cope better with the cold, especially as early humans continued to evolve less body hair. And fire also meant better hunting. Fire could be used to harden spear points, and its flames used to melt pitch, so that the “glue” made could be used to attach flint points onto the ends of spears.

Cooking made humans healthier, too. More nutrients were released from plants. Because some parts of plants are indigestible, they could not be eaten before the advent of fire. Humans ate only seeds, fleshy fruits, and flowers. But after marshalling fire, plant parts such as stems, mature leaves, and enlarged roots could now also be consumed. And cooking saved time. When humans ate only raw, uncooked food, they’d need to eat for over nine hours every day to fuel their brains!

Fire gave humans new powers over the planet. As well as protection from large predators at night, some scholars believe that, in Africa, fire enabled early humans to descend from the trees and take to the land. Fire also meant that early humans could clear large areas of land for their use. And fire also made it easier to travel to colder climates of the planet. This is where the “Have fire will travel” idea comes from. All these powers meant that, in time, humans would migrate and conquer all corners of the planet.

Fire and cooking also meant that early humans spent less time and energy on food. The human digestive system shrank, allowing more energy for growing human brains. And humans made primitive art to record how important fire was to them. They daubed paint on cave walls, making pictures all about animals and the hunt. Maybe the movement of the animals, and the excitement and danger of hunting them, was also an inspiration. But fire and food came first. The ancient prehistoric world, full of incredible cave art painted by early humans many thousands of years ago, would have been impossible for us to have witnessed without fire, as the artists could not have seen in the dark caves!

The rest of the fire story is, as they say, history. Our occasional and dramatic failure to control fire, such as the Great Fire of London in 1666 and the Great Chicago Fire of 1871. The harnessing of fire power through machine inventions such as the steam and combustion engines. The explosive use of fire power in fireworks and gunpowder. The role of fire in our ancient mastery of metal. And our modern overreliance on the thermal energy released by fossil fuels. No wonder fire is often seen as a symbol of knowledge and progress.