This is yet another of those questions I don’t quite remember the context for. I do recall that – around St. Patrick’s Day last year – his preschool did a thing where the teachers messed up the classroom while the kids were out on the playground, and then told all of the children that a leprechaun messed the room up. The kids then made “leprechaun traps”, which they set out overnight. The next day there were no leprechauns in the traps, but each one had a “gold coin” (really a chocolate coin” in it.

My son was enamored, and I suspect that set off the following questions.

“How small is a leprechaun?” he asked.

“They’re small,” I said, holding my hand a foot or so off the floor. “ABout so big.”

“Are mice their friends?”

That left me nonplussed. I’ve read a whole lot of myths and fairy tales in my time, but nothing about leprechauns that I remember. Certainly nothing about leprechauns that included mice.

What is a Leprechaun?


The exact definition of a leprechaun is, well, it’s not precisely exact. It’s not like we can subject them to DNA analysis to determine where they fit in the phylogenetic tree, after all. However, in Fairy and Folk Tales of the Irish Peasantry, W. B. Yeats classifies them among the “solitary fairies” – one of a group of fairies that live a solitary lifestyle and are distinct from the gregarious “trooping faeries”. He says:

“The name Lepracaun,” Mr. Douglas Hyde writes to me, “is from the Irish leith brog–i.e., the One-shoemaker, since he is generally seen working at a single shoe. It is spelt in Irish leith bhrogan, or leith phrogan, and is in some places pronounced Luchryman, as O’Kearney writes it in that very rare book, the Feis Tigh Chonain.”

The Lepracaun, Cluricaun, and Far Darrig. Are these one spirit in different moods and shapes? Hardly two Irish writers are agreed. In many things these three fairies, if three, resemble each other. They are withered, old, and solitary, in every way unlike the sociable spirits of the first sections. They dress with all unfairy homeliness, and are, indeed, most sluttish, slouching, jeering, mischievous phantoms. They are the great practical jokers among the good people.

The Lepracaun makes shoes continually, and has grown very rich. Many treasure-crocks, buried of old in war-time, has he now for his own. In the early part of this century, according to Croker, in a newspaper office in Tipperary, they used to show a little shoe forgotten by a Lepracaun.

The Cluricaun, (Clobhair-ceann, in O’Kearney) makes himself drunk in gentlemen’s cellars. Some suppose he is merely the Lepracaun on a spree. He is almost unknown in Connaught and the north.

The Far Darrig (fear dearg), which means the Red Man, for he wears a red cap and coat, busies himself with practical joking, especially with gruesome joking. This he does, and nothing else.

Lady Francesca Speranza Wilde, writing in Ancient Legends, Mystic Charms, and Superstitions of Ireland repeats Yeats’ etymology, stating that “Leprehaun, or Leith Brogan. means the “Artisan of the Brogue.””. This meaning is generally regarded as “folk etymology“, in which unknown words are replaced by a more familiar word. Modern linguists trace the meaning of leprechaun from the Irish lupracan, which comes from the Old Irish luchorpan, meaning “a very small body”. That word comes from the Proto-Indo-European *legwh- (“having little weight”) plus corpan (a diminutive of corp “body”).

In other words, leprechauns are solitary shoemakers with an inordinate amount of wealth, who sometimes go on benders and sometimes play gruesome practical jokes.  The “red cap” thing is particularly disturbing, because it brings the Scottish Redcap to mind.  And nobody needs an iron-shod lunatic dying their hat in human blood as a cobbler.

Wait, shoes?

Yeah, shoes. Despite the word “leprechaun” meaning something along the lines of “small body”, leprechauns are kind of like the elves in the Irish version of The Shoemaker and the Elves. Except that they live by themselves, wear clothes, and don’t make shoes for humans. But they were worth looking out for anyway. As Lady Wilde put it, “the Leprehauns knew all the secret places where gold lay hid”. If you were clever and quick enough to catch one, you could get them to bargain their gold for their freedom.

You had to be careful with trying to get gold out of a Leprechaun, though – they don’t appear to have minded you trying to get their gold, but they loathed bad manners. Like all fairies, to quote Lady Wilde again, “the Leprehauns can be bitterly malicious if they are offended, and one should he very cautious in dealing with them, and always treat them with great civility, or they will take revenge and never reveal the secret of the hidden gold.”

What about the rainbows?

I found one source for a story involving leprechauns and rainbows. It was on the web site of a local news station in Washington state, though, so I can’t vouch for how authentic it is. It’s the story of a poor husband and wife, and the leprechaun who promises to grant them a single wish. The couple argues about what they should wish for. The leprechaun gets disgusted with their behavior and says “For this, I will not grant any wish of yours. But, since you are in need, I will give you a hint. I have hidden a pot of gold at the end of the rainbow. All you have to do is find it.”

The Oxford Dictionaries says that “at the end of the rainbow” is used to refer to “something much sought after but impossible to attain”, so that would make sense in the context of a leprechaun hiding wealth (and in the context of the story).

So how small are they? And are mice their friends?

This is tricky at best. Lady Wilde describes them as “little” and able “to sit under the hedge” and “under a dock leaf”. I couldn’t find any specifics on the gap beneath a British hedge, but I did learn that “dock” is Rumex obtusfiolius, a plant that grows between 20 and 51 inches (50 and 130 cm). So that gives us a leprechaun height between 10 inches and two feet.

Sadly, I can’t find anything about whether or not they are friends with mice.

Why Is It Cold?

Obviously, it’s winter – it’s February, and I live in the northern hemisphere. And while my son loves the snow, he’s not so certain about this cold nonsense. Particularly first thing in the morning. So one morning he comes lumbering into the living room, still wearing his red flannel footie pyjamas and dragging half of the blankets from his bed. He climbs up on the couch, snuggles down under all the blankets, and peers at the snow through the sliding glass door.

“Why is it cold?” he asks.

“It’s winter,” I answer.

“But why is it cold?”

Well, you stumped me there son. I don’t really know. I know that the Earth tilts on its axis, but the 23 degree tilt doesn’t seem like it moves us far enough away from the sun to make things cold. So, I have no idea.

Fortunatly, the internet does. And the answer, it seems, answers a second question he had: “Is winter over?”

Axial Tilt Is The Reason For The Season


Let’s talk about orbital mechanics for just a moment. The good folk at Hyperphysics have a lovely little set of explanations about where seasons come from, and it all starts with something called the celestial sphere. This is an imaginary sphere with the Earth at its center, a “north celestial pole” above our own geographical north pole, and a “south celestial pole” above our geographical south pole. The sun appears to trace a path through the sky that is tilted at 23.5°to the equator of the celestial sphere, and this path is called the ecliptic.

In truth (and I hope I don’t have to explain this one), the Earth orbits about the sun on a plane and the Earth’s axis is tilted relative to that orbital plane. But seasons seem to be explained in terms of the ecliptic plane. Here’s how they work:

  • The Summer solstice occurs when the Sun’s path on the celestial sphere draws as close to the celestial pole for the hemisphere you live on as possible.
  • The Winter solstice occurs when the Sun’s path on the celestial sphere draws as close to the celestial pole for the hemisphere you don’t live on as possible.
  • The autumn and spring equinoxes occur when the sun’s path on the celestial sphere intersects the celestial equator, with the apparent direction of travel determining which equinox it is.

So, is winter over? Not until the sun “travels” far enough along the ecliptic plane to move from the winter solstice to the spring equinox.

Axial Tilt Is The Reason You’re Cold


Despite my assumptions, axial tilt is why you’re cold in winter and hot in summer. But it has less to do with “distance from the sun” and more to do with “energy per unit of area received from the sun”. See, the Sun generates 6,300,000 mW/cm2 (milliwatts per square centimeter) at it’s surface. This energy spreads out, however, and by the time it reaches the Earth we receive only 137 mW/cm2 at the Equator, on average. This is known as the solar constant.

The Earth is curved, however. As a result, something called the cosine effect kicks in.


Without delving too much into the math – because it’s been forever since I took trigonometry – the actual amount of energy the Earth receives above the equator is decreased, because the Earth’s axial tilt causes the 137 mW/cm2 to spread out over more than a single cm2. To see this in action, turn a flashlight on and point it at a piece of cardboard. Angle that cardboard away from you, and watch how the light spreads out. Since we’re kept warm by the energy received from the sun, the less of it we receive the colder we are.

There’s A Few Other (Grossly Simplified) Factors To Consider

The sun is clearly the big dog in this fight – after all, if the sun went out we would all freeze and die.

There are other factors, though. Altitude above sea level matters, because the thinner the air gets the less heat the air can retain (grossly simplified). Cloud cover plays a role as well – daytime clouds reflect solar energy (reducing the amount absorbed by the Earth) and nighttime cloud cover helps retain heat (grossly simplified). The amount of surface water is important, because water holds more heat than the air (grossly simplified). Ocean currents help distribute this warm water around the globe as well, altering tempertures to a significant degree (grossly simplified).

Really, at the end of the day, anything we say about the causes of winter cold – whether it’s me or a climate scientist – is going to be grossly simplified. Somewhat more grossly simplified, in my case, but simplified no matter what. The Earth is a complicated set of interacting moving parts, after all. But it all starts with the Sun, and our axial tilt.

What Is Money Made Out Of?

My son is five, which means he’s old enough for chores. Right now, he has seven that he’s expected to complete each day. He then earns a dime for each one he completes, and he has to distribute those earnings between three piggy banks: one that he’s going to give to charity, one that he uses to save up for something, and one that he can just take to the store and use for impulse buys. The idea is to start teaching him to save money, and to be charitable with his money. Being five, though, he mostly sees it as a game and as a way to get Star Wars toys.

It’s also led to questions. One evening, as I’m counting out his dimes with him, he asks the question: “What are dimes made of?” Which is a pretty good question. And the only answer I have is “some sort of metal”. Zinc, maybe? I don’t know.

And so I turn to the United States Mint. Because if anyone can answer that question, it’s the people who actually make the coins.

What Are US Coins Made Of?

US Coins

Unsurprisingly, all of the various denominations of United States coins are made of metal. The exact composition varies by coin, however.

  • The Lincoln Penny (One-Cent Coin) has been made of copper-plated zinc since 1982. The entire coin weighs 2.5 grams – 2.4375 grams of which is zinc, and 0.0625 grams of which is copper. This hasn’t always been the case, though. From 1793 until 1962 the coins were primarily made of copper, ranging anywhere from 88% to 100% depending on the year.
  • The Jefferson Nickel(Five-Cent Coin() is a 5 gram coin made of “cupro-nickel” – an alloy of 25% nickel and 75% copper. There was an earlier silver five-cent coin called a “half disme” (pronounced “dime”) that was produced until 1873.
  • The Dime (Ten-Cent Coin) is a 2.268 gram coin made of “cupro-nickel” as well, although it is only 8.33% nickel.
  • The Quarter Dollar (Twenty-Five-Cent Coin) is a 5.670 gram “cupro-nickel” coin, with the exact same proportions of nickel to copper as the dime – 8.33% nickel.
  • The Kennedy Half-Dollar (Fifty-Cent Coin) is a 11.340 gram coin, made of the same 8.33% nickel “cupro-nickel” as the dime and quarter. Interestingly, even though they are legal tender, the mint states that they are “produced as collectibles, not for everyday transaction”.
  • The Native American $1 Coin. First of all, I did not know this was the official name – I’d always heard them called the “Sacagawea Dollar”, because Sacagawea appears on the face of the coin. It’s an 8.1 gram coin made of “manganese-brass”, an alloy that is 88.5% copper, 6% zinc, 3.5% manganese, and 2% nickel. Much like the half-dollar, this coin is legal tender but primarily produced as a collectible.
  • The Presidential $1 Coin is identical to the Native American $1 coin except for the design on the face.
  • There are also an assortment of uncirculating gold, silver, and platinum coins produced by the US Mint. These are generally not used for legal tender.

How Are The Coins Made?

There are four US Mint Facilities that manufacture coins for the country:

  • Philadelphia, which performs “sculpting-engraving of U.S. coins and medals; production of medal and coin dies; production of coins of all denominations for general circulation; production of regular uncirculated coin sets; production of commemorative coins as authorized by Congress; production of medals; and conducting of public tours”
  • Denver, which performs “production of coins of all denominations for general circulation; production of coin dies; production of regular uncirculated coin sets; production of commemorative coins as authorized by Congress; and the conducting of public tours; and storage of gold and silver bullion”.
  • San Francisco, which performs “production of regular proof coin sets in clad and silver; production of commemorative coins as authorized by Congress”.
  • West Point, which performs “production of all uncirculated and proof one-ounce silver bullion coins; all sizes of the uncirculated and proof gold bullion coins; one-ounce platinum bullion coins; the 24-karat one-ounce American Buffalo Gold Bullion Coin; and commemorative coins as authorized by Congress; and storage of silver, gold and platinum bullion.”.

Regardless of which mint makes the coin or which specific coin is being made, the general process is the same. First, blank discs of metal (called “blanks”) are “punched from coiled strips of metal about 13 inches by 1,500 feet in a blanking press” – except for the penny, which just has the blanks pre-made. The blanks are then run through an annealing furnace to soften them up, washed and dried, and then upset – meaning they have a rim raised around their edges. The blanks are then stamped with the dies, turning them from blanks to coins, and then inspected to make sure they were stamped correctly. If you’d like a little more detail, the US Mint has a virtual tour of the process available.

Oh, and those grooves on the edge of the coin? That’s called “reeding“. Originally they were cut onto the coins to make counterfiting more difficult, and to make it obvious if someone was filing (or “shaving”) the coins in an effort to get a little precious metal off the coin before circulating it once more. Clearly we don’t circulate gold and silver coins any more, but the reeding is retained for tradition, and as a way to make it easier for the visually impaired to tell similar sized coins apart.

That’s Cool. But What About Paper Currency?

US Dollars

Currency notes are printed by the Bureau of Engraving and Printing, part of the U.S. Department of the Treasury. And someone there must have a good sense of humor because the web address for the bureau is “www.moneyfactory.gov”, which I find charmingly direct. They print the notes in $1, $2, $5, $10, $20, $50, and $100 denominations. Larger notes ($500, $1,000, $5,000. and $10,000) are still legal tender, but have not been printed since 1945 and have not been issued since 1969.

The notes are printed on a special currency paper composed of 75% cotton and 25% linen, with specialized security threads and watermarks embedded in the paper for everything but the $1 note (along with a 3-D security ribbon for the the $100 note). The actual printing is a combination of green ink, black ink, color-shifting ink, and metallic ink – obviously, exact details of manufacture of the ink are not made public. Much like the U.S. Mint, the BEP has a virtual tour of the currency-making process if you’d like more details.

How Long Would It Take To Drive To The North Pole?

About a week ago, we’re in my car running a few errands. My son is chattering away, happily talking about how Winnie-the-Pooh didn’t really discover the North Pole because he was just pretending. (The Winnie-the-Pooh books are our current bedtime story, if you’re wondering.) Something about the combination of these two facts must have sparked what happened next.

“Dad? How long would it take to drive to the North Pole?”

“Magnetic, or true?” I counter.

“What?” he responds.

The Two Poles

There are two North Poles (and two South Poles as well), the “true” (or geographic) North Pole and the magnetic North Pole. And they do not really match up. So what’s the difference between the two of them? Here’s how National Geographic describes the North Pole:

The North Pole is the northernmost point on Earth. It is the precise point of the intersection of the Earth’s axis and the Earth’s surface.

The North Pole sits in the middle of the Arctic Ocean, on water that is almost always covered with ice. The ice is about 2-3 meters (6-10 feet) thick. The depth of the ocean at  North Pole is more than 4,000 meters (13,123 feet).


The magnetic North Pole is a little more difficult to pin down. Why? Well, let’s start by letting NOAA tell us what the magnetic poles are:

Magnetic poles are defined in different ways. They are commonly understood as positions on the Earth’s surface where the geomagnetic field is vertical (i.e., perpendicular) to the ellipsoid. These north and south positions, called dip poles, do not need to be (and are not currently) antipodal.

“Antipodal”, by the way, is your new word for the day. It means:

  1. Geography. on the opposite side of the globe
  2. diametrically opposite
  3. Botany. (in a developing ovule) of or at the end opposite to the micropyle

So why does the magnetic field move? Because it’s produced by the spinning of the Earth’s inner core – a solid iron ball almost as big as the moon and hotter than the sun that spins a little faster than the Earth’s crust in a massive sea of liquid (or, at least more liquid) metal called the “liquid inner core”. So far, so good. Right?


Now, the full details of what generates the magnetic field are not understood – a fact that I’m certain makes scientists extremely happy. But, as Natural Resources Canada explains, we do understand the basic concepts:

For magnetic field generation to occur several conditions must be met:

  1. there must be a conducting fluid;
  2. there must be enough energy to cause the fluid to move with sufficient speed and with the appropriate flow pattern;
  3. there must be a “seed” magnetic field.

All these conditions are met in the outer core. Molten iron is a good conductor. There is sufficient energy to drive convection, and the convective motion, coupled with the Earth’s rotation, produce the appropriate flow pattern. Even before the Earth’s magnetic field was first formed magnetic fields were present in the form of the sun’s magnetic field. Once the process is going, the existing field acts as the seed field. As a stream of molten iron passes through the existing magnetic field, an electric current is generated through a process called magnetic induction. The newly created electric field will in turn create a magnetic field. Given the right relationship between the magnetic field and the fluid flow, the generated magnetic field can reinforces the initial magnetic field. As long as there is sufficient fluid motion in the outer core, the process will continue.

So why does it move? well, the magnetic field is created by a fast-spinning ball inside a slow-spinning ball. So it wobbles, at an average speed of 10 kilometers per year for the entire 20th century.


So where is it right now? According to the World Data Center for Geomagnetism you’ll find it at 80.4° North, 72.6° west. Or, in other words, Nunavut, Canada.

Magnetic Pole
Right there

How long would it take to drive there?

According to the handy Computing Distances between Latitudes/Longitudes in One Step page, and checking the latitude and longitude of Cincinnati, Ohio (39.1000° N, 84.5167° W), I get the following figures:

  • Geographic North Pole: 3,524.64 miles
  • Magnetic North Pole: 4,144.18 miles

Now, looking at the map above, you would think that driving to either pole would be impossible. After all, there’s ocean in the way! But this is where living in Cincinnati comes in handy – we have a Ride the Ducks tour here!

duck boat

The “Duck Boat” is a World War II surplus DUKW, an amphibious vehicle capable of cruising at 35 mph (56 km/h) on roads and 4.41 mph (7.14 km/h) in the water with an operational range of 400 miles on land (or 58 miles/93 km in the water). I doubt it has the ring mount for the machine guns, though. So, we can do this. In theory, at least.

Eyeballing the map, I’m going to go with an estimate of 90% overland travel to the magnetic North Pole and 65% overland travel to the geographic North Pole. Further assumptions will be:

  • Driving 18 hours a day – my wife has agreed to go along with this mad idea, so we can drive quite a bit. But we still need to stop for bathroom breaks, meals, stretching our legs, and refueling.
  • We’ll be hitting our cruising speed.
  • We don’t get eaten by polar bears.
  • We’re not worrying about mountains.
  • We drive in a straight line, and we don’t get lost.

Getting to the geographic North Pole is roughly 2,291 miles over land and 1233.64 miles over sea. That’s (2,291/35) + (1233.64/4.41) = 345.19 hours. Based on our assumptions, that’s 19 days, 4 hours, 15 minutes. And we would have needed to stop for gas 27 times on the trip.

Getting to the magnetic North Pole is 3,729.762 miles over land and 414.418 miles over sea. That’s (3,729.762/35) + (414.418/4.41) = 200.54 hours. Based on our assumptions that’s 11 days, 3 hours, 23 minutes. And we would have needed to stop for gas 17 times.

Either way, we also get a complimentary duck whistle for the trip.  So my son is going to love this!

Do Frogs Have Teeth?

Once again, I’m without a context for a question I’m working on. I know my son asked me this question: “Do frogs have teeth?” I know it because it’s on my list of questions to answer, right between “How small is a leprechaun? Are mice their friends?” and “Who trained Yoda?”

As you may have noticed, my son has a wide range of eclectic questions.

So, do frogs have teeth? My gut feeling was… maybe? I’m pretty sure I’ve seen pictures of a frog or two with a couple of small teeth that are used to keep insects from escaping. But I haven’t really got a solid idea about that.

Interestingly enough, the answer turns out to be an unqualified “yes”. In Frogs: The Animal Answer Guide, we read:

“Most frogs have small teeth, primarily maxillary (upper jaw) and vomerine (in the roof of the mouth) teeth. Only one species of frog, Guenther’s marsupial frog (Gastrotheca guentheri) of Ecuador and Colombia, has teeth in the lower jaw. Species in the large family of toads, the Bufonidae, lack teeth. Frog teeth are small, mostly cone shpaed, and are used to grasp theirprey. Frogs do not chew their food but instead swallow prey whole. They use their tongue, forelimbs, and even their eyes (by pushing them backward) to force captured prey backward into the mouth and down the throat. Toothless toads are evidence that teeth play a minor role in eating and are unnecessary. In general, frogs with teeth do not bite for defense but only for handling prey.

The African bullfrog (Pyxicephalus adspersus; family Ranidae) has what appear to be large fang-like teeth: two large, bony spines on each side of the lower jaw separated by a smaller spine. These project upward from the lower jaw; and although they are odontoids, not true teeth but formed from bone, they function i the same manner. Although their teeth are not as large as those found in the African bullfrog, lower jaw odontoids can be found in the Sumaco horned treefrog (Hemiphractus proboscideus; family Hemiphractidae) of South America, in the Solomon Island leaf frog (Ceratobatrachus guentheri; family Ranidae), and in the tusked frog (Adelotus brevis; family Myobatrachidae) of Australia.

Most aquatic tadpoles have teeth-like horny plates in rows across the mouth in both the upper and lower jaws. The teeth are made of keratin and are often shaped for effectively scraping algae from rocks or other surfaces.

marsupial frog
Guenther’s Marsupial Frog

So, it seems clear that frogs do have teeth. But they didn’t always have them – or, at least, not the lower jaw teeth. Writing in Re-Evolution of Lost Mandibular Teeth in Frogs After More Than 200 Million Years, and Re-Evaluating Dollo’s Law (published in Evolution – Dr. John Wiens writes that “mandibular teeth were lost in the ancestor of modern frogs at least 230 million years ago (Mya) and have been regained in the last ∼5–17 My”. The rest of the article is an explanation of the molecular data, how it was obtained, and how it was interpreted.

So, cool.  Right?  But what’s this “Dollo’s Law” thing?  Well, Dollo’s Law (aka Dollo’s Law of Irreversibility) states that “An organism is unable to return, even partially, to a previous stage already realized in the ranks of its ancestors.” This is a “law” in the scientific sense, simply meaning that it is the description of an observed phenomenon with no attempt to explain the phenomena.

That’s something important to keep in mind, by the way: scientific laws can be violated, without invalidating the science. Because all that violation does is demonstrate that there are exceptions to the observed phenomena. Dollo’s Law states that an organism won’t re-evolve something, once that something has been lost. Frogs lost mandibular teeth. Gastrotheca guentheri re-evolved them. And the scientific response was not “Oh noes, evolutionary theory is overturned!” It was “We did not see that coming! Neat!”

What If The Oceans Froze?

My son has a fascination with ice. He loves it in drinks (something he gets from me, more than from his mother), and he loves to look at it. We play games with it, like the time I put an ice cube in a bowl for him so he could watch it melt. Or the time we left a cup of water outside to see it freeze. I think he likes the idea that water can turn into a solid, and the fact that it’s cold is just a bonus bit of entertainment.

So we’re driving to church one Sunday, and looking at the snow that’s covered everything – one of the few days this winter where we’ve actually had snow – and he asks me “what if the oceans froze?”

Well, that sounds like an apocalyptic scenario if I’ve ever heard one. “Froze solid?” I reply?

“Yes! So we could ice skate on them!”

Bear in mind that my son has never gone ice skating. So I have no idea where that came from. But the question is interesting. And, sadly, nowhere near as much fun as he’d hope.

When Does Salt Water Freeze?

To start with, ocean water has a much lower freezing point than freshwater. In “Can the ocean freeze?“, NOAA informs us that seawater freezes at 28.4 degrees Fahrenheit (which is -2 degrees Celsius), because of the salt. They also tell us that the average temperature of all ocean water is about 38.3 degrees Fahrenheit (3.5 degrees celsius). So, in theory, to freeze the oceans we’d simply need to reduce the average ocean temperature by 9.9 degrees Fahrenheit (5.5 degrees Celsius).

How cold would it have to get?

Interestingly, the simple truth is that all you’d have to do to freeze the ocean is get the air below the freezing point of the ocean. Then, eventually, you’d manage it. That would require bringing the average equatorial temperature down to that level, and the best figure I could find for that average temperature is 77 degrees f (25 degrees C). That’s a 38.7 degree F (21.5 degree C) difference. This would bring average global temperatures down to 22.3 degrees F (-5.5 degrees C), so things would be terribly cold. To put it in perspective, polar climates have an average temperature of 50 degrees F (10 degrees C).

Killing Frost

A killing frost is a temperature that will kill a plant entirely – not just damage the extremities. Corn and soybeans will die below 28 degrees F. Wheat is a little hardier, depending on the growth stage, but will pretty much die at 24 degrees F (-4 degrees C). So if it got cold enough to freeze the oceans, we’d be living in a permanent killer frost.  Which is another way of saying that we’d be in huge trouble.

Snowball Earth

Interestingly, this may have happened before. There is something called the Snowball Earth hypothesis, that says the Earth may have been frozen like this some 650 million years ago. Equatorial temperatures would have been around what present day Antarctic temperatures are like now – which means an average range of -67.18 degrees F (-55.1 degrees C) in Vostok to 22.46 degrees F (-5.3 degrees C) in the Antarctic Peninsula. There’s a whole lot of disagreement about this theory, though, so take it with a grain of salt until and unless more information comes along.

How Do You Make Chocolate?

Valentines Day is coming up, and my son’s preschool is – like most preschools and elementary schools – going to have a party. My wife is making homemade candy for his class, and he (and three of his friends, and the mother and grandmother of those friends) helped. I missed out on the candy making, though, because I was at home getting our laundry caught up.

When we first told him about the project, he was excited. Because, you know, candy. The very first question he asked was “How do you make chocolate?”

“Well,” I explained, “you melt the chocolate in a double boiler and…”

“No, no. How do you make chocolate?”

Beans, I guess? I think I know that chocolate comes from something called a carob bean, but I’m not even certain about that. I know it’s some sort of bean, though, partly from watching an episode of Good Eats on the subject. So, let’s see if we can’t get an answer!

Where Does Chocolate Come From?
chocolate tree

This is a cocoa tree, also known as a cacao tree. Formally, it’s Theobroma cacao, part of the Malvaceae family (the “mallows”, which also include okra and cotton), which is part of the Malvales order, which is part of the Plantae kingdom. No surprise there, really. Kew Gardens says that

The scientific name Theobroma cacao was given to the species by the Swedish botanist Carl Linnaeus in 1753, when he published it in his famous book Species Plantarum. Theobroma means ‘food of the gods’ in Latin, and cacao is derived from the Nahuatl (Aztec language) word xocolatl, from xococ (bitter) and atl (water).

They go on to note that cocoa trees are native to Mexico, Central America, and northern South America, and have been introduced to a number of African and Asian countries. It’s an evergreen with small yellowish-white to pale pink flowers, and generally grows along river banks in the shade of larger trees in a rain forest. When pollinated, the flowers develop into reddish-brown berries.

cacao berry

How Is Chocolate Made?

It turns out that pretty much every chocolate company on the internet has a “how is chocolate made” page. This information is a synthesis of several of them, but all of them agree on the basics. First, the berries (also known as “pods” are harvested. This is something that can generally be done twice a year. The pods are cut open, and the seeds and the white pith (called baba inside are removed.

cocoa pod

The seeds (which are what we generally think of as the “cocoa bean”) are cleaned, but the white pulp is left in place to help develop flavor. They are then fermented, either by being piled in a heap or stored in boxes. Either way, they are left to ferment for between two and nine days. Once fermented they are dried (requiring one to two weeks), graded, and packed for shipment. The processor cleans the beans (again), then roasts and shells the beans to remove the “nibs” – the meat of the bean. These nibs are finely ground into “cocoa mass” (aka “cocoa liquor), a fine powder. At this point, there are two things you can do:

1. Press the cocoa liquor. This creates cocoa powder, and cocoa butter.
2. Make chocolate.

To make dark chocolate, you combining the cocoa mass (or the appropriate volumes of cocoa powder and cocoa butter) with more cocoa butter and sweetner (usually sugar). Milk powder is added to the mix to make – wait for it – milk chocolate. Either way, the mix goes through a process of “conching”, which is when you heat and mix and heat and mix the mixture until the chocolate takes on the desired texture and flavor. Why’s it called “conching”? Because you use a machine called a “conche” to do it.


Finally, the chocolate is poured into appropriate moulds and tempred – that is, brought to a specific temperature to help it solidify evenly.
What’s White Chocolate?

Related to chocolate is white chocolate. This is made by mixing cocoa butter with milk and sugar and other flavoring ingredients as desired. The FDA specifies that it must

contain “not less than 20 percent by weight of cacao fat as calculated by subtracting from the weight of the total fat the weight of the milkfat, dividing the result by the weight of the finished white chocolate, and multiplying the quotient by 100. The finished white chocolate contains not less than 3.5 percent by weight of milkfat and not less than 14 percent by weight of total milk solids, calculated by using only those dairy ingredients specified in paragraph (b)(2) of this section, and not more than 55 percent by weight nutritive carbohydrate sweetener.

There is apparently some controversy about whether or not white chocolate is actually chocolate, since it contains no chocolate liquor – just a byproduct of processing chocolate liquor. The FDA sometimes gets roped into this, since it regulates food in the United States, but they don’t take a stand other than to place it as a category of Cacao Products. For my part, I don’t really care. Chocolate or not, I’ll eat it.

So, What Was That Carob Thing?

Now, remember how I thought chocolate came from something called a carob bean? Well, this is a carob tree (aka locust bean and St. John’s bread).

carob tree

Formally, it’s Ceratonia siliqua, part of the Fabaceae family, which is part of the Fabales order, which is part of the Plantae kingdom. Which is a fancy way of saying that you have to go back a ways on the phylogenetic tree to find a common ancestor between cocoa and carob. It is native to the eastern Mediterranean, Arabian peninsula, and north Africa. And it grows pods too.

carob pod

These pods (not the seeds!) can be processed into a brown powder that can be used as a chocolate substitute. How well it substitues is really a matter of taste – I ate it as a child and found it acceptable in candy bar format, although it was a bit gritty.