Christmas with The Naked Scientists

JRR Tolkien's elves are tall and imposing. JK Rowling's house elves are small but not crafty. So where do Santa's elves fit in with the other elves? Sally Le Page was tasked with getting to the bottom of this magical mystery and she started by finding out more about the origins of the Christmas elves from fantasy literature expert, Dimitra Fimi, from the University of Glasgow...

Dimitra - Definitely from the 1860s and on, we see a lot of images of Santa accompanied by elves who helped him make the toys. So that goes back to traditional beliefs about elves helping people. We have in older times brownies or hobs or hobgoblins: the elves can make things in the traditional belief.

Sally - So you've mentioned hobgoblins and brownies and fairies. Do you think that these are different entities and we are just getting a bit looser in how we are naming them?

Dimitra - They were always looser. So the names have always fluctuated. If anything, today, we more or less stick to elf or fairy and these are the most widespread, the most commonly known ones. So it's actually become less variable.

Sally - That suggests that to look at a biological cause for how they're related to each other and why Christmas elves are small, actually we shouldn't pay too much attention to the English name that we give them.

Dimitra - No, not at all. No. It's about their nature. It's about what they do and what is their role in the way we understand the world around us.

And that means I need to know who the Christmas elves are most closely related to if I want to find out why they're so small and who better to ask than a biologist who specialises in both evolutionary family trees and magical creatures, Dominic Evangelista, from (rather aptly) Adelphi University. And it turns out he has been tackling this very question...

Dominic - I collected all of this data about all of these different kinds of elves and other creatures, which we hypothesised were closely related. This was information on their morphology - so how they look - information on their behaviour. And we have one group in our tree that we call the true elves. These are where the elves from Lord of the Rings like Elrond and Legolas, this is where they go. They're large, tall, very humanoid. We had another grouping, which we can call dwarves, and these are generally less humanoid. Dwarves are obviously shorter than the true elves. And then we had a final grouping in our tree that we call the pixies. This is a new nomenclature, excuse me, gnome-enclature...anyway. The pixies are small, but they have different kind of magical powers than either dwarves or elves.

Sally - For our discussion, the most important grouping are the dwarves. Obviously with dwarves we think of Snow White and the seven dwarves, but you've put Christmas elves in with the dwarves. Can you explain your reasoning behind that?

Dominic - Yeah. That's probably our most interesting finding here. When you think about it, it does make a lot of sense. You mentioned Snow White's seven dwarves, and I think there's a lot of similarities between Snow White's seven dwarves and Christmas elves. They're both very short. They're both kind of cheerful. Well, I guess some of them are cheerful.

Sally - A few are grumpy.

Dominic - Yeah, that's true. At least one. And if we're comparing to other dwarves, like in Lord of the Rings, these are creatures that like to build things; they're very crafty. They're good with their hands. They have have lots of tools. And that is, I think, the main feature of Christmas elves.

Sally - Did they come from an ancestral elf-like creature that was small and then stayed small, or was the ancestral relative of all of these groups tall and Christmas elves have since evolved to be small?

Dominic - This is a good question. Currently with the knowledge that we have presently, the answer to this question is not really known. It could go either way. Every species on Earth, including Christmas elves and the other magical creatures, they are products of both their ancestry and who they originated from and products of their modern adaptations. So it's unclear yet if Christmas elves' form is more adaptive to their current conditions or their form is inherited from their ancestor.

So the question remains are Christmas elves small because they evolved from small dwarves and so it's all just chance, or is there an adaptive advantage to being small? I figured elves are somewhat like humans, so I should speak to someone who has looked at how and why body size has changed in the various human species across the millennia. And that led me, Manuel Will from the University of Tübingen.

Manuel - There's one really cool thing that we could use also for the elves. It's the so-called 'hobbit' from Flores

Sally - Of course!

Manuel - Homo floresiensis, from the island of Flores in Southeast Asia. And that one is really cool not just because it's dubbed 'the Hobbit', which I like a lot, but also it only stood about a bit more than one metre. So these creatures lived on the Earth around a hundred thousand years ago. That's already when our species Homo sapiens existed.

Sally - Do you think that it's possible to know if Christmas elves just evolved from another dwarf-like creature that was small and so are small by chance or whether it was because of an adaptation?

Manuel - I think that's super difficult to disentangle because it's basically unknown, but I would venture for another kind of explanation. It is an adaptive explanation, which I think could explain the small body size in elves and it's so-called 'island dwarfism'. So again, we talk about dwarves here as well, but also about islands. And there's a really cool thing with many animals, not just humans, that when you see them living on isolated islands, there's a cool thing that normally larger-bodied animals when they get to these islands, they get smaller, they 'dwarf', so to speak. That probably has to do with the fact that on these islands, it's much more difficult to get enough food to sustain large bodies, but also at the same time, there's less pressure of predators, so things that might kill and eat you yourself. Normally a good buffer against that is having a large body, but you don't even need that anymore. And funnily enough, that still the most parsimonious explanation for why Homo floresiensis is so small, likely because it's an adaptation to the island living on Flores.

Sally - So the real life hobbits started off a little bit bigger and then became smaller as they evolved isolated on this island?

Manuel - Exactly. Because the current idea about the family tree of Homo floresiensis is that Homo floresiensis is a descendant of Homo erectus, which is much older and much larger. It's not definitely proven, but it's certainly my favourite hypothesis. And it could work for the elves. Where the elves live, that is also a very isolated environment where maybe they don't get enough food from Santa, but certainly there's also no predators there for them, right? So maybe they just don't have to have big bodies.

And I think we've solved it. Comparing Christmas elves to Tolkien's elves turns out to be a red herring and Santa's elves have actually evolved from dwarves, which explains why they're so good at crafting things. And so Father Christmas probably took a small group of dwarves to the North Pole where they were then cut off from mixing with the other dwarf species, and over time they shrank in size due to island dwarfism.

It doesn't matter where you are or how old you might be, when it snows, there's always a great temptation to go outside and have a snowball fight. But some snow just doesn't cut it. Either it's too powdery to hold together, or it's so hard that it could be classified as a weapon. To clear up this conundrum, Tricia Smith spoke to Gareth Rees and Becky Dell, in search of the science behind that satisfying splat...

Tricia - I visited the Scott Polar Research Institute at the University of Cambridge to find out what makes snow stick.

Gareth - Snow is a mixture of ice in the form of pretty small crystals, and air, and nearly always some liquid water as well.

Tricia - Does snow always have a little bit of water in it or can it sometimes exist without water?

Gareth - This is not completely known at the moment, I think. But what we suspect is true is that there is always a tiny bit of liquid water in snow. If the temperature of the snow is not too far below zero Celsius, say down to minus five minus ten, then there can be a noticeable amount of water, maybe 1%.

Tricia - So why is it that some snow will pack down when I, when I squeeze it and some won't?

Gareth - The main difference between kinds of snow that will compress into a nice snowball, the kind that you can throw satisfactorily and the kind that doesn't, that just stays as powder and falls apart again, is really its temperature. The powdery stuff is too cold. What you want to happen when you make a snowball is that you want to weld the ice crystals together. And the way you do that is you apply some pressure to the snowball, you squeeze it with your hands. Ice is unusual as a material in that when you apply pressure to it, its melting point actually decreases. So it melts a little bit when you squeeze it and the water, then refreezes when you take the pressure off, so when you stop squeezing the snowball, but now what you've got is ice crystals that have been welded to each other by more ice. So the thing becomes mechanically stronger than it was. So it's a little bit denser and quite a lot stronger, so it won't fall apart immediately.

Tricia - When I was at university, I was shown an experiment where they hung a metal wire on a cube of ice and they hung weights off each end. And what happened was the wire passed through the block of ice, but it didn't leave a gap. There was ice left behind as well. So can you explain that experiment to me?

Gareth - That experiment is usually called regelation, that just means refreezing, and it's really a good model of what happens when you make a snowball. The weighted wire is applying pressure to the ice and that succeeds in melting the ice. But above the wire, the pressure is lower again, so the water refreezes to ice. So what happens is that there is a little area of melted ice below the wire, but reformed ice above the wire. So the wire just travels down through the ice refreezing behind it, as it goes. And then eventually the wire drops out at the bottom, but the ice hasn't been cut into two.

Tricia - One of the interesting properties of snow, or of water and ice, is that ice floats on water. So are those things related?

Gareth - Yes, these things are related. What happens in ice, is that the water molecules, the H2O molecules, they arrange themselves in a very specific way. The forces between the molecules are very strong. So they have a very fixed idea about how to arrange themselves, and it's actually quite open. If you melt it into water, the average distance between the molecules actually decreases. So water is more dense than ice, and that's the reason why ice floats in water. And it's also the reason why the melting point of ice decreases when you squeeze it, because you're trying to force it into a smaller volume and it can do that by turning into water.

Tricia - Where in the world would we find snow that is the best for making snowballs?

Gareth - It would need to be somewhere not too cold. So I wouldn't go to the middle of Antarctica to have a snowball fight. I think we'd just find powder snow there. I think you'd want to be somewhere on the edges of regions that tended to get a lot of snow, edges of mountain ranges, fringes of cold regions.

Tricia - Who'd have thought a snowball fight in Antarctica might not be the best idea. Well, just to be sure, I reached out to my friend, who's in Antarctica right now. She agreed to go outside, make a snowball and let us know how it went.

Becky - My name's Becky Dell, and I'm a glaciologist working at the University of Cambridge. Currently, I'm in Antarctica on Alexander Island, living in Fossil Bluff hut, working on George VI ice shelf. Luckily it was pretty snowy this morning, so the snow is now fairly wet and malleable. However, a couple of days ago, it was much drier here, and it was almost too powdery to form a snowball. I'm going to try and make a snowball now, and I'll talk you through what happens.

Snowball - <snowball noises>

Becky - I'm not going to lie, the snow's actually pretty tough. It's formed a ball pretty quickly, but it's a fairly angular jagged ball, and I'm having to apply quite a lot of pressure. So rather than a ball, I'd call this... a cube. I've made a snow cube. No one to throw it at though, because they're all inside having a cup of coffee. So I'm going to go and join them.

Tricia - I'm not sure I'd want to be hit by a snow cube... sounds painful. So there you have it. Leave the skiing for the mountain tops because the snow in the valley is much more likely to weld together into the perfect snowball. Before I left, Gareth had one more, very important piece of advice for me.

Gareth - The very best snow for a snowball is the snow that's right next to you, because that's when you want to make a snowball. So if it snows in your garden, use that snow.

Whether you're a fan of Slade or The Progues, the fact remains, that during this time of year many of us will listen to the same songs we played last year, and the year before that... and the year before that! Harry Lewis set out to see if he could get to the bottom of why novel Christmas music struggles to make it into the charts... 

Daniel - I would wonder whether you could answer this question empirically, with science and empirical evidence. One thing that you would have to do is define a Christmas song or a Christmas hit as you put it. Does it need to be commercially successful? Do you want to measure that by its position in the charts or the revenue it generates during a certain period. Then the second question is, does Elton John or Ed Sheeran, qualify as potential music for Christmas just because it's released at the end of November, or do you really mean Christmas music in terms of it has a Christmas theme?

Harry - Looks like I'm gonna need a hand. Luckily, Ian Cross emeritus professor of music and science at Cambridge University agreed to meet me at West Road Concert Hall to iron out the creases.

Ian - Good you could operationalise as effective in removing money from people's wallets. What it is about a song that does that is variety of things. It's the structure of the song, but it's also what it is up against what competition is up against. New Christmas songs have a real problem because they're up against an intense amount of competition from the songs that are trotted out year after year after year and flourish for the Christmas period.

Harry - And competition is further exacerbated by the length of the festive period.

Daniel - A summer hit can be popular in the Northern hemisphere during say June and September. The same song can be a summer hit and popular in the Southern hemisphere in other months. This is different to Christmas, which means that you have a lot of competition in these say six or seven weeks around Christmas.

Harry - That's not all.

Ian - In this country it's getting dark, it's getting miserable. It turns out that when it gets dark and miserable, we tend to prefer music that is not very arousing, often calm or melancholic. On the other hand, as it gets lighter, we tend to prefer music that is more arousing, more urgent, more intense. Now, Christmas is happening at the same time across the globe. Here it's getting cold and miserable in Australia. It's doing the opposite. It's getting sunny. Admittedly, it is bizarre to have Christmas on the beach in the 18 hour day sunshine.

Harry - This is something you've tried and tested.

Ian - It is, it's, it's very odd. Yes, but the same music is likely to pervade the environment. It might be that Slade's 'And here it is Merry Christmas' is a little more popular in Australia than it might be in the UK, simply because it's very upbeat, very arousing and it fits with the long days in Australia.

Harry - Firstly, a Christmas hit has to Christmassy and I'm not gonna be moved on that. Okay. I think the best thing I can do is catch up with a rather talented friend of mine. It's time to take a look at those popular Christmas hits and see what I can learn. Conrad Godfrey. He's a musician, YouTube curator transcriber, and he also sings in a barber shop quartet called Sound Hypothesis, they're are current UK national champions, you know, as you do.

Harry - Merry Christmas Conrad.

Conrad - Merry Christmas, Harry, come on in.

Harry - Thanks very much. Where's the piano?

Conrad - Through here.

Harry - Conrad tells me that a lot of popular Christmas music employs a compositional technique known as chromaticism. I better let him explain this one, eh?

Conrad - Chromaticism meaning the colour that you get when you introduce, if we're talking about the keyboard, it's going beyond the white notes and into the black notes to put it simply. White Christmas, for example, how does that go? It goes, I'm dreaming of a White Christmas. It goes completely out of key and explores loads of different kind of terrain.

Harry - Is that normal for popular music? This exploration of the keyboard?

Conrad - No, I would say it depends on what you're talking about. If we take a song like Justin Bieber's mistletoe, that's an example of a Christmas song that I would say actually is basically a pop song. I'd say one of the reasons for that is because it's not using a lot of this jazzy influence. It's just using very simple four chord progressions and the melodies staying very tonal. By simply for the chords he's playing, you could add in what, in the jazz world they call upper extension. Do something like this perhaps, make it a bit more Christmasy. Right.? It's the most beautiful time of the year, lights fill the streets spreading so much cheer, I should be playing in the winter snow...

Harry - Funny how that drums up nostalgia. It does, it feels more Christmasy to me.

Conrad - Yeah. Right, it does. It's sixties, fifties inspired orchestral sounds really, where there's so much hidden complexity. There's lots going on and you don't really notice this when you're listening to the song, all those complexities, all those complex key changes and rich jazzy voicings are hidden. I think that's what those nostalgic styles did so well. There's this other theme that I've noticed in some of these Christmasy songs when I was doing a bit of research that I don't really think I've heard anyone comment on, but it's actually this kind of trick of using descending major scale to evoke the sound of church bells on Christmas day. I think that songs, for example, like walking in a Winter Wonderland is the same thing, and have yourself a Merry little Christmas as well.

Harry - It's pulling on these themes that we associate as well with nostalgia with Christmas.

Conrad - I think you see that in quite a lot of arrangements. You should look out for that one, the descending scale to evoke the bells.

Harry - Conrad gave me some final advice. If you aren't gonna use his techniques, you're gonna need to throw in a lot of jingle bells or reference to this time of year instead, a little bit like Justin Bieber's mistletoe. I think what I'm learning is that tradition really plays on nostalgia. That certainly seems to be the case for Christmas music.

Ian - Now, there's interesting effect of what happens when you're exposed to music continuously, initially your preference for it increases, then it probably decreases because you've been overexposed.

Harry - Does that mean that when I was younger, I might love something by Boney M, but over the years that's gonna start to decrease and I might start to dislike the Christmas music that I did as a youngster.

Ian - That's possible. There's also another effect, which is that we tend to form quite intense affective attachments to the music that we heard in early teenage years when we were forming our identity. And that attachment to that music tends to persist, irrespective one might almost say, of quality.