If My Hand Set On Fire, Would It Hurt?

I don’t actually remember where this question came from, or why my son asked it. I mean, I suspect it was inspired by playing a video game. Or maybe from watching cartoons. I just have “If my hand set on fire, would it hurt? How bad?” in my notes, with no context whatsoever.

That happens, sometimes. I’ve got a [i]bunch[/i] of questions I jotted down, and many of them lack context. But, in this case, it makes a fun follow-up to my last article.

Sources of burns

To start answering his question, let’s start with how you can get burned. More things than just fire can burn you, after all – just ask your skin, after a day at the pool without sunscreen. In fact, the John Hopkins Medical Library provides four different sources of burns:

  • Thermal burns. These burns are due to heat sources which raise the temperature of the skin and tissues and cause tissue cell death or charring. Hot metals, scalding liquids, steam, and flames, when coming into contact with the skin, can cause thermal burns.
  • Radiation burns. These burns are due to prolonged exposure to ultraviolet rays of the sun, or to other sources of radiation such as X-ray.
  • Chemical burns. These burns are due to strong acids, alkalies, detergents, or solvents coming into contact with the skin or eyes.
  • Electrical burns. These burns are from electrical current, either alternating current (AC) or direct current (DC).

So, if my son’s hand was to be set on fire, he’d experience a thermal burn. Alternately, if he got a sunburn he’d have a radiation burn, if he poured lye on his hand he’d have a chemical burn, and if he stuck his finger in a live lightbulb socket he’d get an electrical burn. He’d also have parents doing their best to stay calm until he was taken care of, but that leads into an entirely different question of the “would you still love me if I did something stupid?” type.

(For the record, he’s never actually asked that question. But the answer is: “Yes, I would. I might not be happy with your behavior, but I’d still love you. Now take your fingers away from that electrical socket.”)

Ultimately, each of these sources of burns has some unique characteristics. But they all have the same basic effects.

Let’s talk about skin

Your skin has three layers: the epidermis, the dermis, and the hyodermis. The epidermis is the outer layer, composed of four to five layers of skin cells that protect the underlying layers. These cells manufacture and store keratin, a tough and fibrous protein that also (in a slightly different form) makes up our fingernails and hair and the horns of a rhinoceros. The epidermis also contains the skin pigment melanin, meaning that much of our conceptions of race aren’t even skin deep. The living layers of the epidermis are covered with layers of dead, keratinized cells that flake off over time. Beneath the epidermis is the dermis, two layers of connective tissue that contain blood and lymph vessels, nerves, hair follicles, sweat glands, and other structures. Finally, the hypodermis is connective tissue filled with more blood vessels and subcutaneous fat that serves to connect the skin to the bones and muscles.

“Solid burn, Branch.”

Returning to the John Hopkins Health Library, we learn that there are three classifications of burns – and you’ve probably heard what they are: first-degree, second-degree, and third-degree. Each of these relates to how deep the burn penetrates into the skin. First-degree burns are also referred to as superficial burns, and only affect the epidermis. It’ll be red and painful, dry to the touch, and lacking blisters.

Second-degree burns are also referred to as partial thickness burns, and both the epidermis and dermis are damaged. The skin will still appear read, but it is likely to be blistered and swollen.

Third-degree burns are also called full thickness burns, and this is where it gets really bad. The hypodermis is also damaged in a third-degree burn, and parts of the body below the hypodermis may also be involved. Parts like muscles, tendons, and bones (some sources call this a fourth-degree burn when this occurs). Third-degree burns will look whie or charred, and there tends to be no feeling in the burn site. Why? because the nerves have been destroyed.

Burns are further classified by burn percentage, which estimates the total area of the body affected by the burn. This is done on a “rule of nines”, in which body coverage is estimated in multiples of 9.

The chart doesn’t call out a hand specifically, but it would probably be considered 4.5%.

How much would it hurt?

There are a number of pain scales. The one I found first, and will be using as an example, ranks from 1-10 (well, technically 0-10, but 0 is “No pain. feeling perfectly normal.”). So, here’s the levels:

  1. Very light barely noticeable pain, like a mosquito bite or a poison ivy itch. Most of the time you never think about the pain.
  2. Minor pain, like lightly pinching the fold of skin between the thumb and first finger with the other hand, using the fingernails. Note that people react differently to this selftest
  3. Very noticeable pain, like an accidental cut, a blow to the nose causing a bloody nose, or a doctor giving you an injection. The pain is not so strong that you cannot get used to it. Eventually, most of the time you don’t notice the pain. You have adapted to it.
  4. Strong, deep pain, like an average toothache, the initial pain from a bee sting, or minor trauma to part of the body, such as stubbing your toe real hard. So strong you notice the pain all the time and cannot completely adapt. This pain level can be simulated by pinching the fold of skin between the thumb and first finger with the other hand, using the fingernails, and squeezing real hard. Note how the simulated pain is initially piercing but becomes dull after that.
  5. Strong, deep, piercing pain, such as a sprained ankle when you stand on it wrong or mild back pain. Not only do you notice the pain all the time, you are now so preoccupied with managing it that you normal lifestyle is curtailed. Temporary personality disorders are frequent.
  6. Strong, deep, piercing pain so strong it seems to partially dominate your senses, causing you to think somewhat unclearly. At this point you begin to have trouble holding a job or maintaining normal social relationships. Comparable to a bad non-migraine headache combined with several bee stings, or a bad back pain.
  7. Same as 6 except the pain completely dominates your senses, causing you to think unclearly about half the time. At this point you are effectively disabled and frequently cannot live alone. Comparable to an average migraine headache.
  8. Pain so intense you can no longer think clearly at all, and have often undergone severe personality change if the pain has been present for a long time. Suicide is frequently contemplated and sometimes tried. Comparable to childbirth or a real bad migraine headache.
  9. Pain so intense you cannot tolerate it and demand pain killers or surgery, no matter what the side effects or risk. If this doesn’t work, suicide is frequent since there is no more joy in life whatsoever. Comparable to throat cancer.
  10. Pain so intense you will go unconscious shortly. Most people have never experienced this level of pain. Those who have suffered a severe accident, such as a crushed hand, and lost consciousness as a result of the pain and not blood loss, have experienced level 10.

I couldn’t find any pain chart rankings for burn pain, partially because pain is a subjective (although real) phenomena. The Chicago Clinic explains, however, that

Burn pain can be one of the most intense and prolonged types of pain. Burn pain is difficult to control because of its unique characteristics, its changing patterns, and its various components. In addition, there is pain involved in the treatment of burns as the wounds must be cleansed and the dressings changed. Studies have concluded that the management of burn pain can be inadequate, and such studies have advocated more aggressive treatments for pain resulting from burns. Lastly, some burns can be mentally traumatic and/or physically disfiguring and lead to psychological pain that must be addressed, as well.

So there’s that.

Can Metal Turn Into Fire?

The three of us – me, my wife, and my son – are on our way home from dinner yesterday, and my son’s been talking excitedly about a video game he got to play in a store.  “And then I knocked him into the water,” he announces, “and then I knocked him into the air, and then I won!  Daddy didn’t win a lot, though.”

“I made the mistake of trying to figure out what the buttons do,” I add.  “Our son just pushed things at random.  It’s nice to see that button-mashing is still a strategy.”

“Can metal turn into fire?” my son asks.

Eh?  Where did that come from?  My wife and I look at each other quizzically.  “It can melt,” she says, slowly.

“But can it turn into fire?”

“Do you mean ‘can it burn?'” I ask.

“Yeah!”

“I… think so?”

Can metal burn?

Brief answer: Yes. And in different colors.

Like I told my son, I think so.  Long ago, I was told that burning is just a special form of oxidation (aka “rusting”).  I don’t remember who told me that, or when, or why, so I don’t know that I can trust it.  Also, I vaguely recall that thermite is a metal that burns, and that titanium can burn.  So, yeah.  I’m utterly ignorant on the subject.

Let’s start with “burning”.

Conveniently, a while back I wrote an article titled “When Ice Is On Fire, Does The Ice Melt” where I discussed the concept of burning.  Here’s what I wrote:

Burning, more properly called a combustion reaction, is a little more complicated. There’s an entire subfield of chemistry called thermochemistry that deals with burning (or, more properly, the energy release from a combustion reaction). In general, though, you need a compound to combust and an oxidant to react with the combusting compound, and some energy to get it started. The oxidant and the combusting compound then combine in a chemical reaction to produce one or more new compounds, and since the reaction is exothermic the process of making the new compound(s) generates more energy than it gives off.

Yes, that does mean that once you get a combustion reaction started it will continue as long as it has combustible compounds and oxidants. That’s why fire spreads.

It turns out that I’d missed two important concepts when I wrote that article, though:  flash point and ignition temperature.  The flash point is the lowest temperature at which a combustable substance vaporizes into an ignitable gas, while the ignition temperature is the lowest point at which a combustable substance vaporizes into a gas that will self-ignite.  Note that word “combustable”, though.  Not every substance has a flash point or ignition temperature, because some substances (such as water and other combustion reaction products) are simply not combustable.

Look, we’ve been patient.  Can metal burn?

Well, some can.  If they’re combustible, which gets to the best definition I’ve seen in a long time:  “A combustible metal is defined as any metal composed of distinct particles or pieces, regardless of shape, size or chemical composition that will burn.”  Literally, a metal is defined as a metal that can burn if it is a metal that burns.  Although, in fairness, “burns” means “sustains ignition”.

The combustible metals that are :

And because I know you’re curious, here’s some sample solid metal ignition temperatures.  Bear in mind that, for comparison purposes, a Bic lighter can reach temperatures of 3,590.6 F (1,997 C):

  • Aluminum:  1,832 F (555 C)
  • Barium:  347 F (175 C)
  • Calcium: 1,300 F (704 C)
  • Iron: 1,706 F (930 C)
  • Lithium: 356 F (180 C)
  • Magnesium: 1,153 F (623 C)
  • Plutonium: 1,112 F (600 C)
  • Potassium: 156 F (69 C)
  • Sodium: 239 F (115 C)
  • Strontium: 1,328 F (720 C)
  • Thorium: 932 F (500 C)
  • Titanium: 2,900 F (1,593 C)
  • Uranium: 6,900 F (3,815 C)
  • Zinc: 1,652 F (900 C)
  • Zirconium: 2,552 F (1,400 C)

Hang on.  I have so many questions now.

Yeah, probably.  Let me anticipate them.

A metal doesn’t have to be a “combustible metal” to burn.  Any number of other metals will burn as well, but only as long as you apply heat.  Combustible metals, however, sustain burning even after the outside heat source is removed.  Aluminum will burn like a log, but copper will only burn as long as you apply sufficient heat.

Your pocket lighter will probably not set your cast iron skillet on fire, for the same reason that it will not set a log on fire.  A significant percentage of the object that you are trying to burn has to be heated to the flash point before it will catch fire.  You could probably set a super-thin iron wire on fire with a lighter, but you’d need a larger and sustained flame to ignite something big.

 

Oh, and here’s two more useful facts to know:

  • “Burning combustible metals can extract water from concrete, intensifying burning to cause spalling and explosion of the concrete.”
  • “Water applied to alkali metals will result in hazardous decomposition, ignition or explosion.  Alkali metals include lithium, sodium, potassium, cesium and francium.”

So, if you do manage to set your cheap fake diamond on fire?  Call a professional.

 

Why Does Size Matter Not?

I’ve been home sick for a couple of days, and I’m feeding my son breakfast before getting him off to kindergarten and then collapsing on the couch. He loves it. He’s taking the opportunity to ask me questions (“how would you blow up a planet?”), and talk to me, and show off his progress reading.

“Dad,” he asks, “what did Yoda mean when he told Luke that size matters not when your ally is the Force?”

“Well, son,” I say, trying to use this as a teaching moment, “it’s all about how he lifted the X-wing. Did he use his muscles, and drag it out of the swamp?”

“No,” my son said.

“You’re right. He used the Force.” I leaned forward, just a little. “And he meant that, if you believe in yourself and believe you can succeed, you can do anything you want.”

He considered that, then last ones at me. “Dad?”

“Yes, son?”

“Would you rather fly an X-wing, or the Death Star?”

This is going to be a little different, isn’t it?

Yep. Believe it or not, this isn’t a science blog. It’s a blog dedicated to trying to answer my son’s questions. It’s just that, most of the time, he asks questions that I can answer with science.

Size matters not

This really isn’t one of those questions. I mean, sure. There are probably studies on confidence and how it generates success. But that’s not the point, not really.

My son is six. To him, the world is a huge, exciting place filled with wonder and possibility and excitement. And, thanks to him, I’m being reminded that the world is filled with wonder and possibility and excitement. So, as I see it, it’s my job to encourage him and teach him and help him take advantage of everything the world offers.

That starts with confidence.

See, I’m well aware that there are things that are by definition impossible. But I’m also aware that, all too often, we look at things that are merely difficult and declare them “impossible”. “I can’t get out of debt.” “My family can’t make it on one income.” “I’ll never get in shape.” “I’ll never be able to retire.” A million fears become a million reasons to never try.

I don’t want my son to learn that. Not from me, anyway. “Dad,” he’ll say, “I’m going to build a robot!” Or he’ll declare to me that he’s going to build a speeder bike, or a lightsaber, or buy a house next to us so we won’t get lonely, or that he’s going to fly. And it would be easy to accidentally crush his dreams, in the name of “teaching” him.  Instead, I try to respond with this: “Cool! That might be hard, though. How should we start?”

“So certain are you. Always with you it cannot be done. Hear you nothing that I say?”

For the record, we have never built a robot, or a speeder bike, or a lightsaber that works outside our imaginations. That’s mostly due to the fact that sticks and rocks and Legos and paper aren’t the optimal components for such things. But we’ve spent hours working on them, and chasing each other with them, and playing and learning.

My son’s got plenty of time to learn that some things may very well be actually impossible. Right now, though, he’s learning a more important lesson: if you fail, and you still want to do it, try doing it a different way.

“Size matters not, when your ally is the Force.” Sure, I can’t teach my son to move an X-wing with his mind. But I can teach him that it can be moved, and that he can use his mind to figure out the way. And I can teach him to try again, and try something different, if he doesn’t succeed. And to remember that you don’t fail unless you give up.

In the process, maybe I’ll learn it again for myself.

What Are Crystals Made Of?

It’s summer, and my son and I are walking home from preschoool and he’s exploring the area and looking at everything. As he does, he stops at a smallish boulder that’s been left at the corner of a road by a landscaper. “Daddy!” he calls, “Look!” So I go and look. He’s pointing at a band of what I think is quartz, rippling through the stone. “What is that?”

“Those are crystals,” I tell him. “Like the ones we saw at the museum. Remember them?” We’d just recently been to the Cincinnati Natural History Museum, and one thing they had on display was a collection of different crystals and geodes.

“Oh,” he says, staring at the rock. “They’re pretty.”

“Yes,” I agree, “they are.”

“What are they made of?”

Uhm…

What is a crystal?

To begin with, let’s hit Merriam-Webster up. They define ‘crystal‘ as:

  1. quartz that is transparent or nearly so and that is either colorless or only slightly tinged
  2. something resembling crystal in transparency and colorlessness
  3. a body that is formed by the solidification of a chemical element, a compound, or a mixture and has a regularly repeating internal arrangement of its atoms and often external plane faces
  4. a clear colorless glass of superior quality; also : objects or ware of such glass
  5. the glass or transparent plastic cover over a watch or clock dial
  6. a crystalline material used in electronics as a frequency-determining element or for rectification

What is a Crystal, a page on University of California Berkeley’s College of Natural Resources site, says:

Something is crystalline if the atoms or ions that compose it are arranged in a regular way (i.e, a crystal has internal order due to the periodic arrangement of atoms in three dimensions).  Gems are described as amorphous if they are non-crystalline.

Crystals characterized by well developed crystal faces (external surfaces) are described as euhedral . Crystals do not always show well developed crystal faces seen on euhedral examples.

A crystal is built up by arranging atoms and groups of atoms in regular patterns, for example at the corners of a cube or rectangular prism.

The basic arrangement of atoms that describes the crystal structure is identified. This is termed the unit cell.

Crystals must be charge balanced.  This means that the amount of negative charge must be compensated by the same amount of positive charge.

 

So what are crystals made of?

Atoms.

More usefully, Crystal Structure of the elements says that the only elements that don’t form crystals are promethium, astatine, radon, francium, einsteinium, fermium, mendelevium, nobelium, lawrencium, rutherfordium, dubnium, seaborgium, bohriumhassium, meitnerium, darmstadtium, roentgenium, unubium, unutrium, unuquadium, ununpentium, ununhexium, ununseptium, and ununoctium. Of all of these, only radon is found naturally on Earth, and the idea that it has no crystal structure is contradicted by Elements Database which states it has a cubic crystal structure. So it’s quite possible that the others have them as well, and we just don’t know because they tend to fall apart before we can see what they do.

The most common crystals on Earth tend to be made out of the most common elements on Earth. Why? Because they’re available to make crystals. These elements are oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg) in the proportions seen below.

I’ll be honest here, and say that I expected carbon (C) to be much higher on that list. You know, what with it being so vital to every living thing we see. But no. Carbon is part of the 1.5% “other”, and makes up only 0.15% of the Earth’s crust. Go figure.

Most likely, the crystal that caught my son’s eye was either feldspar or quartz – the boulder was granite, after all, and granite is largely made up of those two crystals. Quartz is silicon dioxide (SiO2), it comes in a variety of colors depending on the impurities in the crystalline structure, and it ranges from transparent to opaque. Feldspar is actually a group of three related minerals (KAlSi3O8, NaAlSi3O8, and CaAl2Si3O8) which can resemble quartz. I’m certain a minerologist could figure out the difference, but I certainly couldn’t. Not from a purely visual inspection, anyway.

Why Do Birds Poop And Pee At The Same Time?

I don’t know if my son was watching a nature program, or if he’d been talking about this at school, or what. All I know is that, as we were walking into the condo one day, he suddenly stops and points. “Look dad! An owl!”

I stare along the side of the building, wondering which of the trees he’s talking about. Or is it perched on a balcony, maybe? “I… don’t see it,” I say.

“It’s right there!” he exclaims, pointing. “Oh, no. It’s a squirrel. Look, dad! A squirrel!”

“I don’t see it,” I tell him. “But my eyes aren’t as good as yours.”

He nods at that. “Dad?”

“Yes, son?”

“Why do birds poop and pee at the same time?”

…that is not what I thought he was going to ask.

Do they poop and pee at the same time?

This seems like the first place to start, because I’m not at all certain they do. I mean, sure. I’ve heard this before. But it wouldn’t be the first time I’ve found that “received wisdom” is wrong and that something I thought was true wasn’t true. However, in this case, it seems that received wisdom is correct.

This is going to be more than I wanted to know, isn’t it?

Hey, you’re the one reading this.

Pretty much all animals produce ammonia (NH3) during digestion. It’s a side effect of the breakdown of proteins, which all animals need whether they’re carnivores or herbivores. Ammonia is, however, toxic (doses of 350 mg/kg of weight can kill), which means that animals have to deal with it in some fashion. And by “deal with” I mean “get rid of”.

Generally speaking, mammals will mix it with some of the waste carbon dioxide (CO2) they produce through breathing and convert it into urea (CO(NH3)2) – a far less toxic chemical (the lethal dose is 8,471 mg/kg) that also happens to be water soluble. Mammals then, generally speaking, expel it (along with other waste chemicals) in the form of urine.

Birds don’t do this. Birds, it seems, don’t even have bladders.

Sigh. Tell me more.

To start with, most birds convert ammonia into uric acid (C5H4N3O3, lethal dose around 5040 mg/kg) instead of urea. The other thing they do, which is the reason why they simultaneously poop and pee, has to do with anatomy. See, bird excretory systems work a lot like lizards. They have kidneys, of course, and ureters (the ducts that allow urine to leave the kidney). However, they lack bladders. Instead, they have something called a cloaca – a multipurpose organ that serves as both the reproductive and excretory organ.

The urine enters the cloaca through the ureters, where it is pushed up into the large intestine. The large intestine re-absorbs much of the water content, allowing the urine to be concentrated into a thick paste before it is passed by the bird. since uric acid dries white, this lends bird droppings their distinctive appearances.

So, in short, birds poop and pee at the same time because of evolution.  And because they aren’t equipped to poop and pee separately.

Why Do Sharks Eat So Many People?

“Dad?” my son asked as we got out of the car. “Why do sharks eat so many people?”

I assume he’d seen something about sharks at school, but the question still came out of nowhere. Thirty seconds before, he’d been telling me about his school’s Mardi Gras party and asking me if I felt better (because I’ve been sick, which is why this article still isn’t looking at the fossils he found). So, I put my mind to it. “I don’t think they do,” I answer.

“They don’t eat people?” he responds, sounding skeptical.

“Well, they can,” I concede. “But they don’t eat people all that often.”

“Why not?” he asks, and I swear he sounds disappointed.

“Well, a lot of them are kind of small. And we aren’t the kind of things they normally hunt.” I’m trying to remember shark facts, now. “Most of them are probably just wondering what we are, and people get scared of them and think they’re attacking.”

“Why do people get scared?” he asks.

I shrug. “Why did you get scared of them, when we went to the aquariam?”

“Because they look mean!” Then he grabs my hand. “Since you’re not feeling good, can we take a break and play Star Wars?”

Do sharks eat a lot of people?

This is one of those questions where I really hope I told my son the right thing, because I was working from half-remembered articles I’d read years ago, and memory is a fickle, tricky thing. Fortunately, it turns out that the University of Florida maintains the International Shark Attack File (ISAF), which they describe as “the longest running database on shark attacks, has a long-term scientifically documented database containing information on all known shark attacks, and is the only globally-comprehensive, scientific shark attack database in the world”.

Before we dive into the numbers, though, it’ll be important to define two terms the ISAF uses: provoked attacks and unprovoked attacks.

  • An unprovoked attack is edfined as “incidents where an attack on a live human occurs in the shark’s natural habitat with no human provocation of the shark.”
  • A provoked attack, on the other hand, usually occurs “when a human initiates physical contact with a shark, e.g. a diver bitten after grabbing a shark, attacks on spearfishers and those feeding sharks, bites occurring while unhooking or removing a shark from a fishing net, etc.”

The ISAF reports that 2016 was a pretty typical year, with a total of 150 alleged shark attacks. Out of those 150 attacks, here’s how the results broke out:

  • 81 were classified as unprovoked attacks (53 total in the United States, 43 of which were in Hawaii).
  • 37 were classified as provoked attacks.
  • 12 were sharks biting boats (aka “boat attacks”).
  • 1 was a shark eating part of an already dead human cadaver.
  • 12 had insufficient evidence to prove a shark attack.
  • 7 were determined to be attacks by other marine animals (including a barracuda and an eel).
  • 5 were determined to be abiotic injuries (that is, an environmental injury – scraping coral or rock, for instance).

So, in the fairly typical year of 2016, there were 118 total shark attacks on humans (131 if you count the boat attacks and the scavenging). 2015, by contract, hit 98 unprovoked shark attacks- the highest yearly total on record. On average, shark attacks result in 6 to 8 fatalities per year (depending on what period of time you average out), but 2016 only had 4 shark attack fatalities. Statistically, surfers are most likely to be attacked 958% of the total), followed by recreational swimmers and waders (32.1% of the attacks).

That’s not a lot of attacks, is it?

No, not really. In fact, there’s a whole lot of animals that are much more likely to kill you. According to the BBC[http://www.bbc.com/news/world-36320744], venomous snakes kill an estimated 50,000 people each year, rabid dogs kill an average 25,000 people each year, crocodiles kill an estimated 1,000 humans per year, and hippos kills an estimated 500 people per year. All of which makes the paltry 6-8 shark kills each year pretty tame.

friendly-shark

Still, it’s probably best not to do this unless you know what you’re doing.

The ISAF provides some other interesting comparisons. The odds of dying from a shark attack are 1 in 3,748,067. Fireworks are about 11 times more lethal (odds of death: 1 in 340,733), sun and heat exposure are 273 times more lethal (odds of death: 1 in 13,729), and the flu is 59,664 times more likely to kill you (odds of death: 1 in 63).

Why do shark attacks get so much attention, then?

Rarity, in my opinion. Rarity and shock/

See, we notice things that appear out of the ordinary. According to the CDC, heart disease is the leading cause of death in the United States (614,348 deaths in 2014), followed by chronic lower respiratory diseases (147,101 deaths), accidents (136,053 deaths), stroke (133,103 deaths), Alzheimer’s disease (93,541 deaths), diabetes (76,488 deaths), and influenza and pneumonia (55,227 deaths). Most of those get no attention at all, unless they’re really spectacular or they happen to someone famous. But death by animal attack? That’s unusual, particularly in the United States. And particularly because we like to think we’re outside the food chain. Homo sapiens sapiens is, realistically, the ultimate alpha predator and one of the dominant environmental forces on the planet. It’s unsettling to be reminded that we’re still animals, and that we can still become prey.

Also, sharks inhabit an alien environment that we can only meaningfully visit with the benefit of technology. A wolf or bear attack happens on dry land, so the surroundings aren’t inherently hostile to us. But sharks? A shark could kill us with their own environment, even if the bite isn’t fatal. So, they seem frightening.

Just in case I am one of the unlucky ones, any tips?

Actually, yes. Here’s what the ISAF says: “If one is attacked by a shark, we advise a proactive response. Hitting a shark on the nose, ideally with an inanimate object, usually results in the shark temporarily curtailing its attack. One should try to get out of the water at this time. If this is not possible, repeated blows to the snout may offer a temporary reprieve, but the result is likely to become increasingly less effective. If a shark actually bites, we suggest clawing at its eyes and gill openings, two sensitive areas. One should not act passively if under attack as sharks respect size and power. “

Why Do Tornadoes Suck Things Up?

My six-year-old nephew spent the weekend at my house, which delighted my son to no end. The end result was the sort of excited chaos you might expect – lots of six-year-old bickering, and toys strewn everywhere, and strange non sequitur laced conversations. At one point, tornadoes came up. I don’t know why, because I wasn’t paying attention to the start of that conversation. But my nephew declared that he’d seen a tornado, and that his mom had made them get in the closet. And my son responded that you didn’t get in the closet, you got in the [i]tub[/i], because we’d had a tornado warning once and our front bathroom is the safest place in our condo for that sort of thing. So they argue the merits of bathroom versus closet for a few minutes, and then my son looks at me. I smile, preparing my “it depends on the house” explanation for the question I’m sure is coming.

“Dad?” my son asks. “Why do tornadoes suck things up?”

All right. So that isn’t the question I expected.

What is a tornado?

The National Oceanic and Atmospheric Administration has a page titled The Online Tornado FAQ, and I’ll be referencing it a lot over the course of this question. To begin with, I’ll just quote their answer to the question:

According to the Glossary of Meteorology (AMS 2000), a tornado is “a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud.” Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven’t found it so simple in practice, however, to classify and define tornadoes (per this essay by Doswell). For example, the difference is unclear between an strong mesocyclone (parent thunderstorm circulation) on the ground, and a large, weak tornado. There is also disagreement as to whether separate ground contacts of the same funnel constitute separate tornadoes. Meteorologists also can disagree on precisely defining large, intense, messy multivortex circulations, such as the El Reno tornado of 2013, compared to the parent mesocyclone and surrounding winds of damaging intensity. It is well-known that a tornado may not have a visible funnel. Mobile radars also have showed that tornadoes often extend outside an existing, visible funnel. At what wind speed of the cloud-to-ground vortex does a tornado begin? How close must two or more different tornadic circulations become to qualify as a one multiple-vortex tornado, instead of separate tornadoes? There are no firm answers.

In other words, a tornado is a vortex, very much like an atmospheric whirlpool. In an oversimplified fashion they form under basically the same conditions – our atmosphere is described by the same fluid dynamics that describes the behavior of water, after all. Moving air hits a barrier – in this case, denser colder air – and twists back on itself. The air is still moving into the barrier, however, so the air that is deflected back picks up speed thanks to the conservation of angular momentum, creating a vortex.

But, like I said, that’s the oversimplified explanation. Here’s what NOAA says on the subject:

The truth is that we don’t fully understand. The most destructive and deadly tornadoes occur from supercells–which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. [Supercells can also produce damaging hail, severe non-tornadic winds, unusually frequent lightning, and flash floods.] Tornado formation is believed to be dictated mainly by things which happen on the storm scale, in and around the mesocyclone. Recent theories and results from the VORTEX programs suggest that once a mesocyclone is underway, tornado development is related to temperature changes across the edge of downdraft air wrapping around the mesocyclone (the occlusion downdraft). Mathematical modeling studies of tornado formation also indicate that it can happen without such temperature patterns; and in fact, very little temperature variation was observed near some of the most destructive tornadoes in history on 3 May 1999. The details behind these theories are given in several of the Scientific References accompanying this FAQ

What this means is that they’re vortices, and they form just like any other vortex. But, like most things in nature, they’re super complicated and we don’t really quite understand what makes them start.

So how do these tornados suck things up?

The famous “sucking tornados” are “multiple vortex tornados“, and they create what is called a “suction vortex“. Interestingly, the suction vortex has little to do with air pressure, and everything to do with wind speed. That is, the lower air pressure within the vortex isn’t low enough to “suck” things up. Tornadoes aren’t straws. Instead, the speed of the winds traveling up the vortex funnel create the “suction” effect.

Here’s what happens. The secondary vortices of a multiple-vortex tornado orbit the axis of the primary vortex, increasing the wind speed around the primary vortex. When the wind from and around the secondary vortices “turns the corner” – that is, enters the primary vortex and suddenly changes from horizontal to vertical flow – angular conservation causes the wind to pick up an enormous amount of speed. It is this wind speed that lifts objects – cows, trucks, people, roofs, whatever – and hurls them into the air. Note that all tornadoes have this “turn the corner” effect, but it takes the secondary vortices to really get the wind moving fast enough to lift really heavy objects.

Waterspouts and fire tornadoes

My son had heard of waterspouts, and guessed that they were water tornadoes. He was right. A waterspout is literally just a tornado that forms over water and that sucks up water.

Fire tornadoes are a little different. They are similar to actual tornadoes in appearance – except, you know, for the [i]fire[/i] – but are formed by rising surface winds (usually generated by the heat from the fire) that meet turbulent winds to form a spiral of rising flame. They aren’t formed by supercell thunderstorms and aren’t tornadoes. Doesn’t make them safe, mind.