Slow Burn

Isn’t watching a match burn in slow motion a hypnotic sight? Want to know what you’re looking at?

For something as ubiquitous as matches, it strikes me that very few people know what goes into creating fire on the end of a stick. Let’s open the book and illuminate the science behind this burning question.

I’ll stop the puns now.

Having a source of fire on demand was not always such a trivial pursuit that we were willing to give things like matches away for free at the Olive Garden hostess stand. As far back as the 6th century A.D. the Chinese were using sulfur-coated sticks to spread fire from camp to camp, because without fire, you died or ate raw food.

Most of what’s in a match today is a chemical called potassium chlorate, which is really just a good source of the oxygen atoms that every flame needs in order to burn. There’s also a good bit of sulfur, which is what’s doing most of the burning and what gives matches their characteristic smell (and why some people keep them in the bathroom), glue, and inert stuff. The “strike” part of the match was added later, when inventors in the 1800’s added a chemical called “white phosphorous”.

White phosphorous is a common explosive that burns super-vigorously when it comes in contact with oxygen under the right conditions, like when a little heat is added. Unfortunately it works a little too well, and it’s also enormously toxic. It was eventually replaced with a less volatile, less toxic form called “red phosphorous” after factory workers began dying left and right.

So what happens when you strike a match?

If you try striking a common match on regular sandpaper, nothing will happen except that you end up with a handfull of toothpicks. The special red sandpaper has a tiny bit of red phosphorous embedded in it, and when you drag the match across it creates heat. If you make enough heat, a wee bit of red phosphorous gets turned into white phosphorous and starts microscopic explosions. Remember the sulfur in the match head? At regular atmospheric oxygen concentrations the sulfur isn’t very flammable. But add some pure oxygen and heat and sulfur goes ballistic. The tiny sparks from the red-to-white phosphorous release oxygen from the potassium chlorate so that the sulfur is able to burn in a high oxygen environment. 

Eventually, the wood catches, and you try to say the alphabet or something before it burns out.

So it’s more than just a cool slow-motion video, it’s a close-up on chemistry!

A Burning Question? First … sorry. You’ve probably already turned this paper in, because it takes me so long to get through all the questions you guys send in, but in case anyone else is writing a research paper on the “Biological Manifestations of Burns and Possibilites for Evolution of Hominid Daenarysian Flame-Resistance,” here ya go: Bodies are made of cells. Cells are made primarily of proteins, fats (called lipids), nucleic acids (like DNA) and most of all, water. Burns are really just an injury to these cells caused by exposure to high temperatures. The severity depends on how many and which kind of cell gets burned. The burning that happens when we touch a hot iron must be differentiated from the burning that happens inside, say, a campfire. In a campfire we are witnessing combustion. This is the conversion of one type of chemical - long chains of carbons that make up wood, for instance - into simpler carbon chains, like ash. Oxygen feeds the reaction and water vapor is released. Processes like cremation burn a body this way, but it takes very high temperatures (and usually some external propellant) to recreate something like the famous self-immolation of Thich Quang Duc, or when Sarah Conner was toasted by a thermonuclear weapon. We are all aware that the severity of burns ranks into three categories, but you might not know that the more severe burns, while most dangerous, hurt the least. Why is that? Let’s analyze what happens to your cells when you get burned. Depending on the temperature and length of exposure, your cells will absorb a certain amount of heat. The more heat, the deeper the burn and more severe. Let’s pretend we had a thin sheet of cells on a stove and started cranking up the temperature. First the cell membranes, made of lipids and other molecules, would start to lose their shape. Just like olive oil is liquid at room temperature and solidifies in the fridge, so do the fats in your cell membranes respond to extreme temperatures. Next, the long, carefully wound chains of amino acids that make up your proteins would begin to unravel, just like a wrinkle relaxes when you iron a shirt. Instantly, all the machinery of your cells would be unwound and useless, never able to fold up into its active shape. If you’re keeping score, that means you have loose membranes filled with broken proteins. That cell is D-E-D dead. If the temperature gets high enough, the water in the cells will actually boil away! Depending on how hot and long the exposure, you’re left with some region of your tissue that is effectively burnt toast. Of course, it doesn’t end there. Your body recognizes the injury and starts to release a whole mess of emergency signaling molecules around the burned tissue. One of these is called histamine, and it actually causes gaps to form between cells, allowing fluid to leak out. This is why liquid-filled blisters (that you, of course, never pop) form, and also, along with some other causes, why you get the sniffles. Along with the tissue itself, your blood vessels can also get damaged, and unless they grow back (which they don’t always do), you could be left with a pretty bad situation. This is why we give grafts of living skin tissue, so that we can patch a dead region with something that’s still alive. Beyond that, your body’s response to severe burns can be as severe as kidney failure, shock, and loss of immune protection. Basically, in order for humans to progress into fireproof beings, we have two choices: Evolve thermostable proteins that can withstand high temperatures (like hot springs bacteria) along with Teflon-impregnated skin, or stop being made primarily of water. Both are unlikely, although could spawn a good sci-fi story or two. 
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A Burning Question?

First … sorry. You’ve probably already turned this paper in, because it takes me so long to get through all the questions you guys send in, but in case anyone else is writing a research paper on the “Biological Manifestations of Burns and Possibilites for Evolution of Hominid Daenarysian Flame-Resistance,” here ya go:

Bodies are made of cells. Cells are made primarily of proteins, fats (called lipids), nucleic acids (like DNA) and most of all, water. Burns are really just an injury to these cells caused by exposure to high temperatures. The severity depends on how many and which kind of cell gets burned.

The burning that happens when we touch a hot iron must be differentiated from the burning that happens inside, say, a campfire. In a campfire we are witnessing combustion. This is the conversion of one type of chemical - long chains of carbons that make up wood, for instance - into simpler carbon chains, like ash. Oxygen feeds the reaction and water vapor is released. Processes like cremation burn a body this way, but it takes very high temperatures (and usually some external propellant) to recreate something like the famous self-immolation of Thich Quang Duc, or when Sarah Conner was toasted by a thermonuclear weapon.

We are all aware that the severity of burns ranks into three categories, but you might not know that the more severe burns, while most dangerous, hurt the least. Why is that? Let’s analyze what happens to your cells when you get burned.

Depending on the temperature and length of exposure, your cells will absorb a certain amount of heat. The more heat, the deeper the burn and more severe. Let’s pretend we had a thin sheet of cells on a stove and started cranking up the temperature.

First the cell membranes, made of lipids and other molecules, would start to lose their shape. Just like olive oil is liquid at room temperature and solidifies in the fridge, so do the fats in your cell membranes respond to extreme temperatures.

Next, the long, carefully wound chains of amino acids that make up your proteins would begin to unravel, just like a wrinkle relaxes when you iron a shirt. Instantly, all the machinery of your cells would be unwound and useless, never able to fold up into its active shape. If you’re keeping score, that means you have loose membranes filled with broken proteins. That cell is D-E-D dead.

If the temperature gets high enough, the water in the cells will actually boil away! Depending on how hot and long the exposure, you’re left with some region of your tissue that is effectively burnt toast. Of course, it doesn’t end there. Your body recognizes the injury and starts to release a whole mess of emergency signaling molecules around the burned tissue. One of these is called histamine, and it actually causes gaps to form between cells, allowing fluid to leak out. This is why liquid-filled blisters (that you, of course, never pop) form, and also, along with some other causes, why you get the sniffles.

Along with the tissue itself, your blood vessels can also get damaged, and unless they grow back (which they don’t always do), you could be left with a pretty bad situation. This is why we give grafts of living skin tissue, so that we can patch a dead region with something that’s still alive. Beyond that, your body’s response to severe burns can be as severe as kidney failure, shock, and loss of immune protection.

Basically, in order for humans to progress into fireproof beings, we have two choices: Evolve thermostable proteins that can withstand high temperatures (like hot springs bacteria) along with Teflon-impregnated skin, or stop being made primarily of water. Both are unlikely, although could spawn a good sci-fi story or two.