How Coffins Work

Even if you haven't had any personal experience with coffins, you probably have a general idea of what they look like. But why do they look the way they do, and why do so many cultures use them in the first place?

While coffins can't provide impermeable protection for bodies, they still serve as a barrier between a body and the elements. Most comprise a sturdy, outer shell and an interior lining that cushions the body. However, throughout history, families that couldn't afford an elaborate coffin buried their dead in plain, wooden boxes or even simply wrapped in sheets [source: Woodward].

Public health regulations in many developed countries, including the United States, require that coffins be constructed using sturdy materials and sealed permanently to avoid contamination of the earth by the decaying body [source: U.S. Public Health Service]. In less developed countries, however, where central governments are often contested or nonexistent, these kinds of regulations are less common, not to mention less enforceable.

In situations like these, the construction of burial receptacles may also be influenced by a society's geographical location. For example, cultures located in forested areas often construct coffins out of wood, while desert-based civilizations often use materials like stone, clay or papier-mâché [source: Woodward].

As you might expect, coffins used for cremation are slightly different from those used for burial. In order to break down easily, cremation coffins are generally made of light, cheap woods, like particleboard or even cardboard. However, if a viewing is scheduled before the cremation, many funeral homes offer the option of renting an outer coffin for that purpose. When the body is cremated, the outer coffin is removed [source: Wuyi Xinglong].

Although the basic design of a coffin or casket is simple, some more specialized coffins require a great degree of complex engineering. We'll cover that and why picking the wrong coffin might have explosive consequences next.

A coffin's basic purpose is to create a barrier around a corpse. But what happens when that's just not enough? Over the years, the funeral industry has developed some specialized coffins to address a variety of needs and concerns.

One example is the protective coffin, which the American funeral industry has promoted heavily because it features a rubber gasket to provide a more durable seal against earth and elements. Some designs have employed an impermeable seal, which might seem like an attractive option initially. After all, if you're burying a loved one, it's natural to prefer the most secure receptacle available.

However, as a body decays, it produces methane gas -- which, if not allowed to leak out, builds up within the coffin and can literally cause it to explode. Since no one wants that, the industry developed burping coffins, which are protective structures that rely on a permeable seal to protect the body while allowing gas to escape. Although these coffins do add a degree of protection from decay, it's now illegal for funeral providers to claim that these models will preserve the body indefinitely [source: Mitford].

These protective caskets wouldn't have been enough to protect a body from medical students during the early 19th century, though. During this so-called body-snatching period, thieves broke into graves to retrieve corpses for medical education and research. In response, the funeral industry developed more heavy-duty protective measures. Instead of just a coffin, bodies would often be interred in thick-walled vaults, potentially equipped with several locks and staffed by guards. Additionally, a mortsafe, a type of iron cage placed over a vault, might have been secured in concrete over the grave. A locked gate would allow loved ones access to the grave. Not enough money for the more high-tech solutions? Heavy wooden planks or metal slabs placed over the coffin proved difficult for unwanted visitors to remove. Alternatively, stones filling the grave instead of dirt would cause a ruckus if disturbed, drawing attention to would-be body snatchers during the act [source: Shultz].

We'll share one more functional coffin innovation later on, but for now let's take a look at the flip side of coffin functionality: form.

In addition to their practical functions, coffins are a ceremonial aspect of funeral practices in societies all over the world. And, as you might suspect, different cultures have vastly different traditions when it comes to constructing and decorating coffins for their deceased.

For example, in the U.S., relatively easy access to resource materials and formal funeral traditions have resulted in the popularity of elegant, high-quality coffin designs. Funeral homes will often stress respect for the dead as a selling point on a nice coffin. During the funeral, the coffin is often the centerpiece of the proceedings and is likely to be displayed for the mourners during or before the ceremony.

In the modern Western world, coffins are generally made of a sturdy shell and a plush lining. The shell may be made from a hardy wood -- often elm or oak, but sometimes cherry or mahogany -- or a heavy metal like steel, copper or bronze. The lining may be made of taffeta, velvet or a similarly rich (or rich-looking) material with polyester batting, similar to a couch cushion [source: Woodward]. And, just as funereal language is carefully calculated to increase customer comfort, so is coffin design: Many American coffins are produced in warm (or "advancing") colors as opposed to cooler (or "receding") colors that might be associated more viscerally with the concept of death.

As sensitive as the funeral business is, it's still a business. One tactic that the funeral industry has used to sell more expensive coffins is to design inexpensive coffins to be intentionally unattractive, and sometimes downright ugly [source: Mitford]. People who want to bury their loved ones in style must therefore drop more cash to avoid what could be interpreted as sending a beloved friend or relative into the afterlife in a low-quality receptacle. In fact, in some cultures, a grand send-off is a key aspect of showing respect for the deceased -- surviving friends and family will even risk going into debt to give a loved one a proper burial [source: Chinese Ministry of Global Culture].

Other cultures are more ambivalent: In Great Britain and Australia, for example, the coffin and casket industry is far less robust than it is in America, with far less importance placed on the quality or design of a coffin [source: Mitford]. Similarly, the Jewish faith requires that its dead be buried in plain coffins to eliminate any socioeconomic distinction [source: Jewish Federations].

One of the world's greatest unsolved coffin mysteries is the case of the hanging coffins of China -- a phenomenon that has yet to be explained definitively.

China's hanging coffins are a group of coffins in the Bochango Valley, once numbering up to 280 but now closer to 100, which are tucked in caves and under cliffsides between 350 and 400 feet (107 and 122 meters) high. Research has revealed that the coffins were left by the Bo people, an ethnic minority living in what are now the Sichuan and Yunnan provinces of China. Once among China's most common funeral practices, these wooden, unpainted, unadorned coffins date back to as early as 770 to 476 BCE. The most recent is only around 400 years old. But how could an ancient civilization have engineered such a feat? And why?

There's no lack of theories. Some posit that they created earthen ramps supported by planks or wooden scaffolding to allow them to reach the coffins' final resting places. However, although no explanation has been definitively established, the most widely accepted hypothesis today is that the Bo actually lowered the hanging coffins from above with ropes -- marks of which have been found around the coffins' sites [source: China Internet Information Center].

So when so many cultures around the world bury their dead, why did the Bo choose to do virtually the opposite? In Chinese culture, ancestors are highly respected and even revered -- placing them at a location that is physically elevated allowed the living down below to look up to their ancestors in a literal sense. The culture's mythology states that deities reside on mountaintops, which are closest to paradise. By laying their dead to rest there, the living are essentially bringing their ancestors closer to their new home with the deities [source: China Travel]. Cool, huh?

But there's one society that no coverage of coffins would be complete without mentioning. We'll talk about history's most opulent coffins and burial practices next.

The sarcophagi, or literally coffins made of stone, that we've come to know and love through museums and action blockbusters are those of the Egyptian pharaohs.

The most famous of the known Egyptian sarcophagi is that of Tutankhamen, commonly known as King Tut, a young pharaoh who reigned briefly but earned his place in global history through his famous burial suite. When Tut's tomb was discovered in 1922, it was one of the few royal graves that hadn't been almost completely plundered.

Among the various riches explorers found were Tut's three coffins. Surrounding an inner coffin of solid gold were two gold-covered, wood-frame coffins, the outermost designed with the famous portrait of the pharaoh that most of us are familiar with today. The coffin was also decorated with precious stones and pieces of jewelry. (See images of Tut's coffins in our article Was there really a curse on King Tutankhamen's tomb?)

Why such opulence? For the ancient Egyptians, every aspect of a tomb -- especially one belonging to a pharaoh -- was carefully planned and constructed. Tombs were decked out with the deceased's riches and possessions. Pharaohs' tombs, the massive pyramids that still speckle the Egyptian landscape thousands of years later, sometimes even contained servants to provide assistance to the deceased. As you may imagine, these rituals weren't simply taken on a whim; burial proceedings in ancient Egypt were guided largely by the Egyptian Coffin Texts.

The Egyptian Coffin Texts originated primarily in Egypt's Middle Kingdom, the period from 2150 to 1539 BCE. This collection of spells and descriptions of the underworld were designed to see the deceased through the journey into the afterlife. The documents originated from the Pyramid Text, one of the oldest Egyptian religious spells, which was said to guarantee the ascension of royalty to the heavens in the afterlife; it later evolved into the perhaps more well-known Book of the Dead. Where the Pyramid Text was reserved for royalty, however, the Coffin Texts were accessible by all members of society, regardless of class or status [source: Ellison].

Today, these seemingly mysterious traditions often seem like the stuff of fiction.

Unless you work in the funeral industry, your practical interactions with coffins are, we hope, few and far between. Instead, most of us are familiar with coffins through fiction, from campfire tales to mummy and vampire movies.

Many myths claim that vampires sleep in coffins during the day to avoid sunlight. When a suspected vampire is dug up, the body is said to look lifelike, lacking the stiffness and bluish pallor of a corpse. In addition, the coffin may also be filled with blood [source: Encyclopedia of Occultism and Parapsychology].

Perhaps the most widely known vampire story is that of Count Dracula, the title character in Bram Stoker's 1897 novel, "Dracula" [source: Encyclopedia of World Biography]. "Dracula" and the myths that inspired it spawned hundreds, if not thousands, of other vampire stories, from the silent film horror film "]Nosferatu" and Anne Rice's dramatic "Vampire Chronicles" novels to the spoofy "Buffy the Vampire Slayer" TV series and Stephanie Meyer's tween romance franchise, "Twilight."

As with most myths, coffin-based folklore has many of its roots in truth. One reason that these various coffin myths are so permanent -- and potent -- is that when it comes right down to it, the idea of being buried is just plain scary. And if being buried in general is that bad, being buried alive must be far worse. Learn more about this fear and how it led to a few creative coffin innovations on the next page.

The fear of being buried alive has its own diagnosis: taphophobia. The word comes from the Greek taphos, or grave; according to the American Psychiatric Association (APA), taphophobia may result from an early traumatic experience, perhaps involving being trapped in a confined space [source: APA].

Specific phobias like taphophobia usually originate in childhood and dissipate before a person reaches adulthood, but more serious cases will last into adulthood and seldom go away without treatment. Some treatments for taphophobia include cognitive behavioral therapy, a set of psychotherapeutic techniques that emphasize the role of thought in feelings and behaviors, and exposure therapy, in which a sufferer is exposed to triggering situations in a controlled manner [sources: NACBT, APA].

Therapy is common now, but it wasn't in 18th- and 19th-century Europe, when fears of premature burial were spiking. Safety coffins, which are coffins equipped with various mechanisms to alert those above ground that a victim was trapped below, were designed to combat these fears.

Some alert mechanisms included ropes that would ring the church bell or a smaller bell mounted on the grave, a flag that could be raised from below ground, and even small, long-fused firecrackers. Some safety coffins also featured tubes through which an individual unfortunate enough to have been buried prematurely could breathe and receive food and water.

Although safety coffins captured public attention, research has shown that most would have been entirely ineffective due to mechanical faults, and it's unlikely that any were ever used for their intended purpose. However, taphophobia and related fears remain common enough that safety coffins are still available today [source: Australian Museum].