My Favourite Bits of Science

(Part III)

Coming next week: My favourite stock photos of scientists!

The Nerdiest Guy In School
    It's been a while since I've written a blog so firstly, apologies for that.  I've been quite busy the last few weeks because I've been marking exam papers, working on my next book and enjoying the delights of an Ofsted inspection at my school.  It's been a long while since I added to my "Favourite Bits of Science" series but I've finally got a minute to write...and eat...and sleep.   
    In the first installment I talked about my favourite people from science history.  In the second, I discussed science popularisers I look up to and in this third chapter I'm going to write something esoteritc, self-indulgent and weird.  I'm going to talk about my favourite "things" in science.  Not people, not books, not TV shows, not facts...things.  What kind of person writes a blog like that, you ask?  Well, more to the point, what kind of person reads it? 

Favourite Particle: The Charm Quark
    In particle physics, there were originally thought to be three types of quark (correctly pronounced to rhyme with 'fork', no matter what anyone tells you).  The three quarks were named up, down and strange by Murray Gell-Mann, and using them we could explain the behaviour of every atomic nucleus known to man.  Those three particles are really all you need.  But what's interesting is that the strange quark is effectively a down quark with additional mass - as if nature gave the down quark a fat older sister for some reason.  Wouldn't it be a lot neater, therefore, if the up quark had a heavier counterpart too?
    The physicist Sheldon Glashow certainly thought so and proposed that there was a fourth quark hiding somewhere in the quantum wilderness.  This particle was not essential to our theories and wasn't needed to explain any observation, but it made things a bit more pretty, and thus Glashow named it the charmed quark, because its existence would be a charming feature of reality.  His proposed particle was eventually discovered in 1974 and his sentimental optimism was justly rewarded.
    The charm quark doesn't do anything especially different to the other three, but I love it because it reminds me of something important.  You sometimes get the feeling studying physics that nature only does things by necessity and that the governing law of reality is cold, mechanical causality.  The charm quark is a reminder that sometimes the Universe is pretty for no reason.  The Universe doesn't have to have symmetrical neatness, and yet it does.  The charm quark is a reminder that nature isn't only interesting...it's beautiful and that's worth celebrating too.

Favourite Element: Phosphorus
    Phosphorus is the eccentric loner of the periodic table.  The unappreciated genius capable of chemistry no other element would think of.  It is the only atom to regularly form five bonds to others and it comes in a variety of natural states, which is also unusual.  While most elements tend to show up in one state with one colour, Phosphorus can be found as brown, black, white, red, yellow, purple, blue and glow-in-the-dark. 
    Phosphorus is the element which forms the backbone of DNA and is the "limiting reagent" in the biological ecosystem, meaning the entire population of living things on Earth goes up and down in line with the amount of available Phosphorus.  Not only is Phosphorus crucial to life however, it's also an important part of death - being the most toxic element on the periodic table and the basis of most chemical weapons.
    All of these reasons would be enough to make it an element worth taking note of, but my love of Phosphorus actually stems from something simpler and far less sophisticated.  I once accidentally set fire to a chunk of phosphorus during a reaction and, before I began choking on the toxic fumes, I caught a glimpse of it burning and it is one of the most beautiful reactions I have ever seen.  A photograph or video does not do it justice because on film it looks like any normal fire.  But if you see it in the flesh, the flames of burning phosphorus are unique.  They are silvery-white and ripple across the surface of the element like waves on a pond, hugging it as if they don't want to rise into the air.  Even when being destroyed, phosphorus is incomparable.

Favourite Chemical Compound: Ionic Liquids
   There are generally three ways atoms can bond to each other, called ionic, covalent and metallic.  I won't go into the technicals (if you're curious, check out my first book Elemental) but ionic bonding generally goes like this...two small, roughly spherical atoms or molecules stick to each other because of a charge difference.  One molecule or atom is positive, the other is negative and when they pack together they form a rigid lattice, resulting in crystals, salts and rocks etc. because they are tiny, highly charged pellets of matter crammed together in stubborn arrangements.  But there is one bizarre exception.
    If, instead of tiny balls of charge, you have two molecules which are quite big and bulky, the positive and negative charges get spread out across the molecules.  The result is that the charge-attraction gets diluted and when the molecules bind together, it's a weak attraction, meaning they don't form solid structures.  They form liquids.  Something which, prior to the 1930s, was thought to be impossible.
    Ionic liquids have all the properties of salts and crystals, but also the properties of liquids.  They tend to be thick gloopy substances, resembling honey or treacle, and they are usually colourless, yellow or orange.  What's really interesting is that because the particles in the fluid are so loosely attracted to each other, they tumble at a very low rate, so anything dissolved in them also interacts very slowly.  This means you have enough time for complicated reactions to take place and you can tailor your ionic liquid to the reaction you're trying to achieve.
    Ionic liquids fascinate me because they are substances which shouldn't exist...and yet do.  I also spent a whole year studying their behaviour (read more about that adventure here) and I think they're going to be one of the next big things in chemical research.

Favourite Equation: S = k log W
    Sir Arthur Eddington once wrote "If your theory is found to be against the second law of thermodynamics I can offer you no hope; there is nothing for it but to collapse in deepest humiliation".   
    The second law of thermodynamics is one of the most worshiped principles in Science and works its way into everything from data analysis to evolutionary anthropology.  It says, put simply as possible, that energy tends to spread over time.  Things don't become ordered at random, they become disordered and you can't get energy to stay in one place.  Everything from sugar poured on a kitchen table to the fabric of the cosmos itself spreads out, and we call this spread of energy "entropy", defined via the equation above.
    It's a bit hard to talk it through without diagrams and sketches but here goes.  Firstly, you take the number of possible ways energy can arrange itself, represented by the letter W (nobody knows why that letter was picked).  Then you find what's called the logarithm of that number.  That means: how many times do you have to multiply a number by itself to reach the value of W.  It doesn't matter what number you pick to use (typically you use 10 or sometimes the number "e") but once you have that, you multiply it by "k" which is called Boltzmann's constant - a number which relates the energy of particles to how they are moving and the computed answer will give you the entropy of what you're looking at. 
    I love this equation because it's simple enough to write in a few letters and yet it has far-reaching implications.  I once carved a giant version of the equation in the snow of my high school's back field (I'd like to think it's the largest snow-equation ever made) and when Ludwig Boltzmann, the man who came up with the concept of entropy, died, they put the equation on his tombstone.  Which means I have a favourite tombstone as well...

Image Credits
Stock Photo of scientist: madscience
Charm quark symbol: wikipedia
Phosphorus: images-of-elements
Ionic Liquids: iolitec
Boltzmann's grave: tumblr