Hi, you know I've always had a fascination with crystals. As a PhD chemist I used to make them every day. I mean I don't mean make quartz but I used to make you know take chemical compounds, a variety of different types of compounds and you can coax them into forming really almost clear in many cases and coloured crystals.
It's a purification technique used in organic chemistry which is what I did my PhD in. But I thought, you know, I'd share with you what I think are four really fascinating facts about quartz and crystals in general. Do you know, years ago we used to keep time using the steady tick of a pendulum arm, but now what we use is something called the piezoelectric effect. It's when you pass an electric current from a watch battery or a clock battery through a tiny wee bit of quartz and it vibrates.
Exactly! 32,768 times per second. Isn't that amazing?
It vibrates exactly and it's that absolute precision of 32,768 vibrations per second that allows us to keep accurate time and that's why if many watches or clocks that you see will say quartz on them and what the quartz is referring to is the fact that the time is kept by a tiny wee slither of quartz that vibrates exactly 32,768 times a second. Isn't that absolutely amazing? The second thing that I think is really cool is optical fibres. Optical fibres are what we use in our telephone lines. Years ago it used to be metal, I think copper it was maybe, and broadband used to initially be in phone lines and then it was metal wires.
Now it's fibre optics and that means they actually start out as silicate or silicon dioxide, which is pretty much what quartz is made of, silicon dioxide, and it's melted at high temperature. And as it's cooling, they pull it into, engineers pull it into really, really tiny, tiny wee thin fibres about the thickness of a human hair. And they have this property that's called total internal reflection. Now what that means is, let's say this was a wee bit of an optical fibre magnified up. It means as light is coming through it, it bounces inside the fibre.
It goes bing, bing, bing, bing. And it doesn't go out of it. And that's what...
total internal reflection means it reflects internally totally internally inside of it and you don't lose any over which means we can efficiently transmit information through these fiber optics are these optical fibers and the fact that light travels so fast get us 300 million meters per second that's a fast light travels amazing in that so so that's why we call it high speed internet and high-speed telecommunications and it's all made possible because of silicon dioxide which is well quartz essentially. So that's the second really fascinating thing I think fascinating about crystals. Now the third thing I think is really fascinating is the earth's magnetic field protects us, protects all life on earth actually from harmful cosmic rays. So cosmic rays come in from the sun and from you know different parts of the galaxy and If it wasn't for our magnetic field, they would get right through and they can be very, very damaging and harmful to life. So the fact that life is here and has survived millions of years is in large part thanks to the fact we have a magnetic field.
Now, why does that matter? Well, in fact, here's another thing. You've probably seen the Earth's magnetic field.
If you've ever been far enough north, you know, you often see them in Scandinavia, Iceland, even northern Canada. Sometimes a wee bit. Also.
in the southern hemisphere as well, you know, very very tips or ends of the land. And what happens is, we call them the southern lights rather than the northern lights, but I've only ever seen the northern lights, and you see these little waves of green and blue, kind of aquamarine and stuff, and what that actually is, is these charged particles coming down, hitting the Earth's magnetic field and go, you know, like rain on a tin roof going, and it goes, and it bounces off the Earth's magnetic field, and that's what you're seeing. It's the Northern Lights and the Southern Lights, the aurorae borealis and australia borealis I think that's what it is.
What you're seeing is these cosmic rays bouncing off like rain on a tin roof and bouncing off and that's what you see, that's what the Northern and the Southern Lights actually are. But yet the scientists for years wondered where does the Earth's magnetic field come from? How does it actually generate?
Because it was always up for debate. Now some breakthrough research at the Tokyo Institute of Technology a couple of years ago suggested that that it seems quite likely that it's actually the formation of quartz close to the earth's core that powers it, isn't that amazing? So what happens? The earth's core is mostly molten iron, absolutely roasting, roasting hot and the iron is liquid. but it's not just iron in the core because it also contains like silicon and oxygen and carbon and a few other ingredients and what happens is heat begins to rise from the center and that pushes some of the lighter things like like silicon and oxygen are much lighter than iron and it pushes them up like that and as they push up they begin to crystallize into quartz and a lot of the quartz is just the crystallization of molten what is essentially molten rock or magma it's the same stuff that spouts out of a volcano But it's really, really deep down and it crystallizes into quartz and then some other things begin to fall down and then they melt and come back up again and you get this little convection thing and it's believed now that that's actually this crystallization of quartz is actually what's powering the Earth's magnetic field.
Isn't that amazing? It absolutely blows me away. The fact that we are here on Earth today because quartz forms inside the main body of the Earth, it crystallizes into it. silicon dioxide, silicon and oxygen come together and crystallize into quartz as it moves out of the center of the earth. And that's why we're here today, because that produces a magnetic field that protects us from cosmic rays.
Absolutely amazing. So fourth thing, I was going to tell you four things. What's the fourth thing I was going to share with you?
Oh, aye, aye. So earthquakes occur when two plates in the earth's crust slip against each other, they go and they slip and grind. And that's what an earthquake is, you know, you've probably, you know, that shaking of the ground, that's just crustal plates going, crustal plates are like, you know, if you look at a football and you see these regular hexagons, so the Earth's crust is a bit like that, except it's not regular hexagons, they're all different shapes, but they're called, they're called crustal plates. And they're essentially floating, the Earth is molten, you know, so they're essentially floating over the surface, over millions of years, sometimes they float apart, which is why...
Africa and South America look the same. You know, if you cut them out, you could stick them together. It makes me exercise for kids. And you'll see that, you'll learn that millions and millions of years ago, Africa and South America were actually joined, but through what's called plate tectonics, the movement of these crustal plates on the molten magma, they gradually drift apart. And so nowadays you have thousands of miles separating Africa from South America.
But when these plates, grind against each other, they go and they slip sometimes and that's what we feel with the ground shaking during an earthquake. But as you know, you've seen it in the movies, that you end up with big tears in the ground and that's also underneath. Now how does the earth heal those tears, those wounds if you will? Turns out as the molten rock is coming up into those cuts if you will, those tears in the earth's crust, millions and millions of little quartz crystals begin to form inside the cut and as they form out of the molten rock they crystallize solid into solid quartz like that they crystallize solid and it literally binds and it holds the cut together like internal sutures like you know stitches healing a wound isn't that absolutely amazing that it's the crystallization of quartz in that a cut in the earth's crust and that literally heals the wound isn't that amazing I love these kind of things I've always say for many reasons I've always had a real fascination with crystals I just thought I'd share some of that fascination with you today so I'm Dr David Hamilton I'm a scientist have a nice day