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Speaker 1: Even before we could pry open molecules and see the

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Speaker 1: structure of atoms, we knew there was something fascinating going on.

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Speaker 1: There had to be some kind of internal structure there.

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Speaker 1: Why did we think so? How did we know? Well,

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Speaker 1: because the periodic table is periodic. There are groups of

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Speaker 1: atoms with similar behavior. As you march across column by column,

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Speaker 1: atoms in those same columns have similar behaviors conductivity, reactivity.

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Speaker 1: That can't just be random, and of course it isn't.

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Speaker 1: It's because of the structure inside each atom, which was

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Speaker 1: long invisible to us. The structure of the atom is

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Speaker 1: of course dictated by quantum mechanics, which also reveals something

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Speaker 1: about the basic laws of the universe. And now electron

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Speaker 1: structure is the source of torture for high school chemistry

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Speaker 1: students and physics podcast hosts, but it also completely and

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Speaker 1: totally diff finds our world. It's why metals exist, why

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Speaker 1: things are hard or soft, or liquid or solid. It's

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Speaker 1: not magic, but changes to these properties can have dramatic

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Speaker 1: effects on elements behavior, and the nature of our experience.

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Speaker 1: And today we're going to dig deep into what might

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Speaker 1: be the weirdest element on the periodic table. One that

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Speaker 1: isn't just sensitive to quantum mechanics, but to our other

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Speaker 1: great theory of physics relativity. Mercury, and here I mean

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Speaker 1: the element, not the planet, whose orbit was famously predicted

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Speaker 1: by relativity. Is very strange because it's liquid at room temperature.

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Speaker 1: It's the only metal we know that is liquid at

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Speaker 1: room temperature that you can pour without ever heating it up.

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Speaker 1: It's even liquid if you put it on ice or snow.

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Speaker 1: This is knowledge we share with the ancients. The name

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Speaker 1: mercury comes from its Greek name, which I won't try

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Speaker 1: to pronounce, but means watery silver. Why what is so

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Speaker 1: special about mercury? What is going on inside that? Adam?

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Speaker 1: Welcome to Daniel and Kelly's extraordinarily chemical universe.

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Speaker 2: Hello. I'm Kelly Wienersmith. I studied parasites and space, and

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Speaker 2: because I was a child of the nineties and we

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Speaker 2: got ourselves into all sorts of trouble, I had a

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Speaker 2: necklace that was a vial of mercury. Oh no, And

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Speaker 2: now I'm just glad it never got like smashed on

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Speaker 2: me or something.

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Speaker 1: Are you sure it wasn't permeable in some way?

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Speaker 2: It would explain a lot.

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Speaker 1: Folks, Kelly would be so much smarter if it wasn't

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Speaker 1: for that necklace. Oh oh ouch, I mean she's already

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Speaker 1: super smart. I don't think we could handle it even

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Speaker 1: smarter Kelly.

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Speaker 2: Oh good cover. I love it.

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Speaker 1: Well. I'm Daniel. I'm a particle physicist, and I'm not

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Speaker 1: a big fan of chemistry, but I am in awe

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Speaker 1: of its influence over our world.

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Speaker 2: Yeah. I was surprised to see that you picked a

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Speaker 2: chemistry tim. Then you did this to us on purpose,

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Speaker 2: and so let's try to focus on positives for chemistry

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Speaker 2: for like half a second. What was your favorite moment

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Speaker 2: in a chemistry class?

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Speaker 1: Ooh, I remember taking the final and being done with it.

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Speaker 2: Amazing.

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Speaker 3: No.

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Speaker 1: I was recently talking to the daughter of a friend

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Speaker 1: of mine and asking her what she wanted to study

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Speaker 1: in college, and she said chemistry and I said cool. Why?

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Speaker 1: And she said, chemistry is very tactile. It relates to

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Speaker 1: things that are right in front of us. It controls

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Speaker 1: how things operate. It's almost like you can do magic.

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Speaker 1: And she was right, you know, like, particle physics is

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Speaker 1: very cool and reveals the fundamental nature of reality blah

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Speaker 1: blah blah. But it talks about things you can't see really,

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Speaker 1: and so like, how do you know the electrons are

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Speaker 1: following those rules or the quirks are doing this or that,

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Speaker 1: whereas like you can see stuff flow or boil or

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Speaker 1: bond or reflect or whatever. It really does determine the

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Speaker 1: nature of our experience.

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Speaker 2: Yeah, I agree, and I disagree. I agree on like

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Speaker 2: a global level. So I did my senior honors research

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Speaker 2: work in an organic chemistry lab because even though I

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Speaker 2: talk about how much I disliked chemistry, I had a

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Speaker 2: lot of chemistry friends and I was kind of into

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Speaker 2: it for a while.

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Speaker 1: But didn't know that about you, Kelly. Hmmm, oh my god,

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Speaker 1: recalibrating over here.

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Speaker 2: I made so many mistakes in the chem lab, though

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Speaker 2: I'm so lucky I didn't die. But you know, I

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Speaker 2: would mix things together and I'd be like, all right,

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Speaker 2: clear liquid mixed with clear liquid, and it still looks

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Speaker 2: like a clear liquid. Did I do the reaction I

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Speaker 2: was trying to do? I don't know. And so I

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Speaker 2: know there's a lot of stuff where it's like you

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Speaker 2: can see stuff's happening, but there's also a lot of

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Speaker 2: stuff where you have to just like expect the thing

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Speaker 2: happening you thought was going to happen, and it's yeah,

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Speaker 2: I don't know. I like fish. You can really see

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Speaker 2: what's going on with fish.

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Speaker 1: You can see fish guts, but you can't see atomic guts.

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Speaker 1: That's the issue, that's.

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Speaker 2: Right, that's what you can't see the backside attack happening

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Speaker 2: in real time. I think that was a chemistry reaction

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Speaker 2: that my friends and I maybe focus done a little

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Speaker 2: bit too much. But anyway, we had some fun.

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Speaker 1: Yeah. Well, you know, underlying chemistry is physics, and there's

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Speaker 1: a close relationship between chemistry and like quantum physics. It

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Speaker 1: determines the nature of the atoms. And what we're going

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Speaker 1: to discover today is that the answer to the question

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Speaker 1: of the episode might not actually be chemistry, it might

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Speaker 1: be physics.

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Speaker 2: After all all that, I think we just found our

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Speaker 2: video uplip for this episode. You have the right voice

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Speaker 2: for an evil scientist.

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Speaker 1: Left. Wow, I'll put that in my next grand proposal.

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Speaker 2: Okay, so today we're talking about why mercury is liquid

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Speaker 2: at room temperature. And I didn't know the answer to

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Speaker 2: this before reading the outline, and you know, to be honest,

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Speaker 2: since it's a brief outline, I still don't think I

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Speaker 2: know what the answer is, but I will by the

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Speaker 2: end of the hour. And so let's see what our

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Speaker 2: audience thinks about why mercury is liquid at room temperature.

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Speaker 1: So think about it for a moment yourself. Do you

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Speaker 1: know the answer? Is it chemistry? Is it is it

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Speaker 1: some weird combination? Is it physical chemistry. Here's what our

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Speaker 1: audience had to.

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Speaker 3: Say, just characteristics of that particular.

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Speaker 1: Element based off of the chemistry of the items. So

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Speaker 1: this sounds like a will make for a very interesting episode.

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Speaker 3: Mercury may not be very good at sharing its electrons

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Speaker 3: and that's why it is a liquid at room temperature.

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Speaker 4: I think it's because the amount of energy that's required

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Speaker 4: to break the bonds to turn into a liquid is

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Speaker 4: really low, because it's just a bit quake. And yeah,

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Speaker 4: like my son, I think it's because of dragons as.

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Speaker 5: Well, something to do with its electron orbitals.

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Speaker 6: I guess that the heavier the element, the more solid

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Speaker 6: it should be. But mercury is a have metal, so

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Speaker 6: this might not be an adequate explanation. Maybe this is

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Speaker 6: related on how the molecules mercury utforms because of.

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Speaker 3: The way it's electrons behave Actually it has to do

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Speaker 3: with the way that they are bonding or in this

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Speaker 3: case not bonding, so it's a very weak chemical interaction.

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Speaker 1: Maybe it has something to do with how the electrons

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Speaker 1: were arranged.

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Speaker 7: I thought mercury was a liquid at room temperature for

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Speaker 7: a similar reason as to why water is as well,

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Speaker 7: how the bonds between the atoms work and interact.

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Speaker 4: Mercury is liquid at room temperature because it's solid at

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Speaker 4: a different temperature, a lower temperature.

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Speaker 1: I don't really know why metals are liquid at any temperature.

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Speaker 2: I don't know now I'm curious.

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Speaker 5: It's valence electrons are paired, which I guess makes it

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Speaker 5: less necessary for it to form the kind of crystal

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Speaker 5: structure that you get in most metals, because it's outermost

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Speaker 5: electron shell loses electrons easily and does not form strong bonds.

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Speaker 3: Has to do with the specific heat of the substance.

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Speaker 1: I knew, aw forgot.

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Speaker 6: That at room temperature, the chemical bonding between the atoms

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Speaker 6: are weaker than in cold, where they get stronger.

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Speaker 2: I love the answer that they would love to know this.

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Speaker 2: There are so many amazing patterns in the periodic table.

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Speaker 2: I love that curiosity about chemistry. You and I should

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Speaker 2: maybe try to channel that a little bit more.

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Speaker 1: I totally agree with that answer. I think it is

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Speaker 1: amazing the patterns in the periodic table, and I love

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Speaker 1: how it reveals the structure of the universe, and it

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Speaker 1: is very very cool. It's just also very complicated. Wow,

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Speaker 1: it's not easy. So you know, my fear of chemistry

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Speaker 1: is mostly in awe of the people who can do it,

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Speaker 1: because I can't.

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Speaker 2: I found it very difficult. Mostly I was spilling the

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Speaker 2: chemicals on myself or dropping the glassware. But my favorite

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Speaker 2: moment in chemistry actually was the very first college chemistry

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Speaker 2: class I took, where we got the melting point and

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Speaker 2: some other features of some unknown substance, and by calculating

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Speaker 2: these different features of the unknown substance, we were able

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Speaker 2: to figure out what we had been given. And that

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Speaker 2: felt like amazing, like forensic science CSI sort of stuff,

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Speaker 2: and I just loved that. So I have a soft

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Speaker 2: spot in my heart for calculating melting points, which is

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Speaker 2: maybe not something I imagined i'd be saying when I

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Speaker 2: was a kid, but I've never been cool, so I'm

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Speaker 2: leaning in. So, Daniel, what determines melting points?

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Speaker 1: M hmmm, Yeah, this is very cool. You know that

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Speaker 1: we even have melting points for stuff, that things have phases.

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Speaker 1: I think phases are super fascinating. You can have like

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Speaker 1: the same set of atoms and a slightly different temperature.

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Speaker 1: They're dramatically different behavior, right. This is not like a

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Speaker 1: smooth transition where it's like kand of mushy and then

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Speaker 1: kind of gassy. It goes from like solid to flowy.

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Speaker 1: You know, it's really incredible that phases even exist. And

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Speaker 1: I just want to nerrod out about phases for another

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Speaker 1: minute before we dive in, because phases are a much

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Speaker 1: more general concept in science and in physics than just

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Speaker 1: like the state of matter. We use phases to describe

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Speaker 1: any time there are a set of equations that have

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Speaker 1: limited applicability, Like you could talk about Newton's equations for

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Speaker 1: the motion of stuff applied to a certain phase of

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Speaker 1: matter when things are not very massive and not very fast.

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Speaker 1: It's like the Newton phase of mechanics. So I think

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Speaker 1: it's really a fascinating concept because it admits that all

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Speaker 1: our laws are limited, the way that like the laws

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Speaker 1: of fluid mechanics only apply to fluids and the laws

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Speaker 1: of crystal lattices only apply to crystals and not to everything.

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Speaker 1: So anyway, I think that's sort of deep and philosophical.

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Speaker 2: I think I'm not following all of the things that

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Speaker 2: you just said. Still sound like you're talking about phases.

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Speaker 2: So you said something about like how fast something's moving,

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Speaker 2: and to me that makes me think about, you know,

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Speaker 2: the transition from a liquid to a gas or something like,

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Speaker 2: I'm missing the point.

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Speaker 1: No, you're right, and they're all linked to like the

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Speaker 1: behavior of the stuff. But you know, think about like

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Speaker 1: the very early universe. We think there was a time

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Speaker 1: when things were so hot and so dense that even

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Speaker 1: our laws of quantum field theory might not apply. So

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Speaker 1: there's like a phase in the universe when quantum field

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Speaker 1: theory applies, and there's a phase when it doesn't apply. Right,

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Speaker 1: Because it's not like a fundamental theory of everything. It's

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Speaker 1: an approximation that only works under some conditions. In the

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Speaker 1: same way like the laws of the liquid phase of

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Speaker 1: water only work when water is liquid, that don't work

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Speaker 1: when water is solid or when water is a gas.

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Speaker 1: All of our laws are approximate that way and only

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Speaker 1: work in a certain phase.

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Speaker 2: Okay, Right, So when I was in my goth phase.

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Speaker 2: The only thing that works for me was black clothing exactly,

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Speaker 2: and I get it. Phase is a more general word. Yeah, okay,

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Speaker 2: move it on.

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Speaker 1: So what's happening here? The listeners were right. Things melt

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Speaker 1: when the bonds between them loosen. Right. So a solid

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Speaker 1: often is a crystal you have, Like these pieces click

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Speaker 1: together into a crystal lattice. Not everything ends up like

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Speaker 1: a crystal, you know, glass for example, like a big

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Speaker 1: disordered mess. But lots of things click together form a crystal.

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Speaker 1: You can imagine, like the little lego pieces snap together

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Speaker 1: and it's very solid. It acts like a big chunk, right.

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Speaker 1: And that happens because there are bonds between them.

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Speaker 3: Right.

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Speaker 1: These things don't just click together physically. They're just physically

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Speaker 1: sharing the space. They are connected to each other. They

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Speaker 1: are bound together because of what their electrons are doing.

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Speaker 1: So if you have strong bonds between stuff and the

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Speaker 1: stuff doesn't have a lot of energy, you can't wiggle

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Speaker 1: around a lot, then it clicks together to form a solid. Now,

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Speaker 1: heat that stuff up, give it energy. Make those atoms

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Speaker 1: wiggle and jiggle and zoom. If they have enough energy

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Speaker 1: to overcome the power of those bonds, then they will

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Speaker 1: break open. That crystal lattice and they will slide around,

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Speaker 1: and that's how they become a liquid. That's what melting is.

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Speaker 1: It's breaking down the crystal lattice so that the atoms

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Speaker 1: are more loosely bound to each other. There's still connected,

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Speaker 1: there's still some bonds there. It's not totally a gas.

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Speaker 1: Gas is when you give up all connection to each

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Speaker 1: other and they're all just a bunch of independent molecules

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Speaker 1: or atoms, so liquid. When you break those strongest bonds

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Speaker 1: and now you have very weak bonds, so the atoms

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Speaker 1: can flow over each other.

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Speaker 2: Is it just that like some percent of the bonds

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Speaker 2: have broken, or that bonds of a certain type have broken,

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Speaker 2: like all the hydrogen to oxygen bonds have broken, but

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Speaker 2: the carbon hydrogen bonds haven't broken yet. Or does it

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Speaker 2: depend on the molecule that you're talking about.

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Speaker 1: It depends on the molecule, but it also depends on

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Speaker 1: the type. And so for example, after the bonds are broken,

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Speaker 1: there are still some bonds there, but they're weird, very

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Speaker 1: soft intermolecular bonds. You know, you can have like a

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Speaker 1: bond between this water molecule and that water molecule because

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Speaker 1: of its polarity, like maybe they're overall neutral, but it's

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Speaker 1: got a little bit more negative on this side and

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Speaker 1: a little bit more positive on that side, and that

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Speaker 1: can attract the neighboring atom, or they can organize themselves

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Speaker 1: that way. It's sort of a loose bond, whereas when

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Speaker 1: they're tightly bound, then they use a different kind of bonds.

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Speaker 1: You know. The electrons can like literally be shared among

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Speaker 1: them in some kind of lattices, like in metals, the

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Speaker 1: electrons just flow freely, right, You can't even really say

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Speaker 1: which atom they're connected to, They just like flow all

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Speaker 1: around the whole thinking you have really complex energy level

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Speaker 1: structures for those electrons because they're really just shared. It's

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Speaker 1: that one really big atom or one super molecule.

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Speaker 2: You know, you and I might both know more chemistry

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Speaker 2: than we've been letting on secrets coming out today.

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Speaker 1: That's solid state physics.

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Speaker 2: Oh no, all right, I was getting worried there. Okay,

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Speaker 2: So it.

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Speaker 1: Really is about the strength of the bonds. If atoms

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Speaker 1: are capable of making very strong bonds, then it requires

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Speaker 1: more energy to break them, higher temperatures to break them,

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Speaker 1: So stronger bonds between the atoms mean a higher melting point.

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Speaker 1: If there are already very very loose bonds between the atoms,

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Speaker 1: like the atoms don't like the bond at all, or

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Speaker 1: they use none of the very strong categories of bonds,

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Speaker 1: then the melting point is going to be lower because

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Speaker 1: it doesn't take a lot of energy to release the atoms.

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Speaker 1: So we're going to take several steps towards the understanding.

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Speaker 1: The first one is melting point is determined by the

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Speaker 1: strength of the bond. Stronger bonds higher melting point, weaker

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Speaker 1: bonds lower melting point.

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Speaker 2: Okay, I've got that general concept. Can you get give

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Speaker 2: me a little bit more information about what makes for

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Speaker 2: a strong bond.

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Speaker 1: Yeah. So you basically you're asking like, well, what makes

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Speaker 1: the bond stronger, what makes the bonds weaker? Why does

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Speaker 1: it depend on the element? What determines that? And the

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Speaker 1: answer there is the electron structure. The electrons are the

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Speaker 1: things that do the bonding, and so the electron structure

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Speaker 1: is what determines whether the bonds are strong or whether

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Speaker 1: the bonds are weak. For example, one of the most

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Speaker 1: important thing is have the electrons filled up their shells,

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Speaker 1: Like the electrons form these shells around the atom, you know,

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Speaker 1: there's the first energy level, the second energy level. If

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Speaker 1: that outermost energy level is filled, then the electrons in

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Speaker 1: the atom are pretty happy and they don't want to

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Speaker 1: go anywhere. If, however, they're not filled, you have like

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Speaker 1: four out of eight or seven out of eight, then

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Speaker 1: that atom is happy to take another electron, or to

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Speaker 1: share another electron with its friend. So together they have

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Speaker 1: filled shells. So for example, if you have hydrogen, hydrogen

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Speaker 1: can have two electrons in its outer shell, but it's

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Speaker 1: only got one, so it likes to find another hydrogen.

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Speaker 1: So together they have two. They can share those two

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Speaker 1: in a bond. So those two electrons are shared between

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Speaker 1: the two protons, and that thing is really bound together

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Speaker 1: into H two. I know, it's very coozy. Actually, where

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Speaker 1: do they hate each other? What if they're like, oh

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Speaker 1: my god, this guy never does the dishes.

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Speaker 2: Oh I get that. I get that. But they can't

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Speaker 2: get away from each other. Well, you got to turn

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Speaker 2: up the heat so that they can escape.

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Speaker 1: Oh, melting is like chemical divorce. Wow, fascinating. We are

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Speaker 1: liberating these abs. You've heard of women's liberation. Now we're

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Speaker 1: doing proton liberation.

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Speaker 2: I thought it was electron liberation.

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Speaker 1: There you go, yeah, electronic hand proton Yeah.

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Speaker 2: Oh okay, got it.

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Speaker 1: Yeah. So there's a few things that affect whether these

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Speaker 1: bonds are strong or not. One is are the shells filled, right,

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Speaker 1: So do you have a complete outer shell it's like

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Speaker 1: a set of armor, it's hard to penetrate. Or do

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Speaker 1: you have an incomplete outer shell, in which case the

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Speaker 1: atom likes to bond. And we're going to go through

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Speaker 1: some examples later on. You'll see that these patterns emerge

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Speaker 1: in the periodic table. The other is how closely is

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Speaker 1: it holding on to those electrons, because the electrons can

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Speaker 1: be like really far out and sort of a distant

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Speaker 1: outer shell very weakly held, or they could be like

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Speaker 1: really tightly held. If the atom is very very powerful,

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Speaker 1: if it has like a lot of protons in it, it

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Speaker 1: can really hold those electrons close. So that also determines it.

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Speaker 1: So we sort of like two dimensions here to determine

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Speaker 1: whether the bonds are strong or whether the bonds are weak,

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Speaker 1: or is it filled shells is it not filled shells.

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Speaker 1: So filled shells means harder to form bonds, not fieled

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Speaker 1: means easier to form bonds. If the electrons are close,

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Speaker 1: it's harder to form bonds with them because they're held

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Speaker 1: tightly by their nucleus and the electrons are not close,

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Speaker 1: it's easier to form bonds.

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Speaker 2: This is reminding me of the fun conversation that we

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Speaker 2: had in response to a listener question about why life

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Speaker 2: tends to be carbon based instead of silicon based. Yeah,

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Speaker 2: silicon not silicone. I always mix those two up in.

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Speaker 1: Orange County, it's silicone mostly.

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Speaker 2: Actually, Yeah, well I live in Virginia where anyway, we

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Speaker 2: don't need to go there. And the answer ended up

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Speaker 2: depending on a lot of these questions.

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Speaker 1: Yeah, but you're putting your finger on a really important trend,

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Speaker 1: which is that as you go across the periodic table,

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Speaker 1: elements in the same column tend to have the same

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Speaker 1: electron structure. Right, they have like one extra electron or two,

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Speaker 1: or it's totally filled, or it's not right. So the

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Speaker 1: rows in the periodic table reflect the energy levels, and

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Speaker 1: then as you march along the columns, you have the

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Speaker 1: same pattern of the electrons filling up. So you go

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Speaker 1: from left to right in the periodic table, you're filling

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Speaker 1: up that outer shell. And so, for example, the last

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Speaker 1: column in the periodic table all have their last one

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Speaker 1: all filled up because it's the last one, and so

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Speaker 1: that whole column are folks with very filled shells. That's

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Speaker 1: why they're called the noble gases. They don't like to

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Speaker 1: interact with anybody, and that's why they're all on the

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Speaker 1: same column because at the same electron structure, which is

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Speaker 1: why they have the same kind of behavior. And like

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Speaker 1: the first column, all are noble gases plus one, so

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Speaker 1: they all have one extra electron, one only electron in

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Speaker 1: its own last shell really dying to do something with

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Speaker 1: its friends. And so that's why those are all very active.

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Speaker 1: For example, they like to react and they interact. So

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Speaker 1: the electron structure really determines all these properties and the

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Speaker 1: periodicity of the table.

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Speaker 2: Now, I remember sitting in chemistry in high school and

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Speaker 2: being like, all right, I think maybe I have finally

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Speaker 2: memorized how many electrons are supposed to be in each

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Speaker 2: one of these shells, But why are their shells in

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Speaker 2: the first place? Yeah, And I never got a satisfactory answer,

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Speaker 2: And maybe that's why I never could love chemistry until

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Speaker 2: this moment, Daniel, because I'm gonna ask you, can you

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Speaker 2: tell me why are there even shells?

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Speaker 1: And do they sell? Them by the seashore. Right. Yeah,

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Speaker 1: So the answer is, of course, the underlying physics quantum mechanics. Like,

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Speaker 1: let's start with a simple atom like hydrogen. Hydrogen has

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Speaker 1: a proton and it has an electron. Where could that

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Speaker 1: electron be. Well, quantum mechanics says, use the Shorting equation,

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Speaker 1: And Shorting equation says, well, there's a bunch of solutions

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Speaker 1: for where the electron can be, a bunch of places

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Speaker 1: where everything is copasetic and the wave function is happy.

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Speaker 1: But there's a ladder of solutions. It's not a continuous

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Speaker 1: state of solutions. Like let's zoom out and take a

401
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Speaker 1: classical example where we have intuition the orbit of a planet.

402
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Speaker 1: Where can a planet orbit the Sun? Well, classical mechanics says,

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Speaker 1: if you have a certain radius, you need to be

404
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Speaker 1: moving at a certain velocity in order to have a

405
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Speaker 1: stable orbit. Cool, But every radius has a velocity, Like

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Speaker 1: you could orbit the Sun at literally any place. There's

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Speaker 1: an infinite number of available radii. Once you pick a radius,

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Speaker 1: you have to have the right velocity. You'll fall out

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Speaker 1: of orbit or you'll zoom out of the Solar system.

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Speaker 1: But you could pick any radius, any solution works around

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Speaker 1: hydrogen that we like to think of these as like

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Speaker 1: planetary orbits, and there's lots of misleading pop side diagrams

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Speaker 1: that convince you. So these are not orbits, right, These

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Speaker 1: are solutions to the shortening equation, and there's a ladder

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Speaker 1: of solutions. There's a finite number that's like number one,

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Speaker 1: number two, number three. The quantum mechanics dictates that. And

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Speaker 1: an intuitive way to think about why there are a

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Speaker 1: discrete number of solution is to think about how the

419
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Speaker 1: wave function fits around the atom. It goes around the atom,

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Speaker 1: it has to reinforce itself, so when you go around,

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Speaker 1: you have to come back and basically be in the

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Speaker 1: same part of the wave and so you can fit

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Speaker 1: like one wave or two waves or three waves, but

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Speaker 1: you have like three point seven waves, then it's going

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Speaker 1: to interfere with itself and it's not going to be

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Speaker 1: a stable solution. So you want a stable solution of

427
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Speaker 1: the electron around the atom, you have to fit a

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Speaker 1: certain number of wavelengths of the wave function around the atom.

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Speaker 1: So that's why you have a discrete number. That's what

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Speaker 1: causes the shells. And then it gets much more complicated

431
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Speaker 1: if you have more protons and multiple electrons. I mean,

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Speaker 1: you get all the way up to like mercury. It's

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Speaker 1: a mess.

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Speaker 2: So does it have to be waves because electrons aren't

435
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Speaker 2: point particles, they're actually waves, and that's where the wave

436
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Speaker 2: thing comes in.

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Speaker 1: Yeah, exactly. You have the wave function, which is a

438
00:21:49,400 --> 00:21:51,919
Speaker 1: complex value thing, and it is really the thing that

439
00:21:51,920 --> 00:21:54,800
Speaker 1: tells you where the electron can be. And so when

440
00:21:54,800 --> 00:21:56,800
Speaker 1: the electron is in its lowest state, you shouldn't think

441
00:21:56,840 --> 00:21:59,720
Speaker 1: of it like, oh, it's orbiting at a certain radius.

442
00:22:00,200 --> 00:22:03,199
Speaker 1: It's got a probability distribution and that's the minimal stable

443
00:22:03,240 --> 00:22:05,000
Speaker 1: configuration for that state.

444
00:22:05,320 --> 00:22:09,000
Speaker 2: Okay, all right, got it. Chemistry is awful. That's what

445
00:22:09,040 --> 00:22:09,440
Speaker 2: I think.

446
00:22:09,480 --> 00:22:12,480
Speaker 1: The other crucial piece of physics is that electrons have

447
00:22:12,600 --> 00:22:14,880
Speaker 1: this weird behavior where you can't have two of them

448
00:22:14,920 --> 00:22:17,879
Speaker 1: having the same state. They just will not share. You know.

449
00:22:17,920 --> 00:22:20,280
Speaker 1: They're like grumpy siblings. You cannot put two of them

450
00:22:20,280 --> 00:22:23,200
Speaker 1: in the same bed. You need to have different rooms

451
00:22:23,320 --> 00:22:26,320
Speaker 1: or they need to have something different. So the first state,

452
00:22:26,400 --> 00:22:28,400
Speaker 1: you can have two electrons because one can be spin

453
00:22:28,520 --> 00:22:30,960
Speaker 1: up and one can be spinned down. The second layer

454
00:22:30,960 --> 00:22:33,800
Speaker 1: has more energy, so they can wiggle in different ways.

455
00:22:33,960 --> 00:22:36,960
Speaker 1: There's different patterns to have their energy is distributed, so

456
00:22:36,960 --> 00:22:40,440
Speaker 1: there's more options there. But quantum mechanics tells us that

457
00:22:40,480 --> 00:22:43,920
Speaker 1: we can only have one electron per unique energy level,

458
00:22:44,320 --> 00:22:46,919
Speaker 1: and as the shells get bigger, there's more options for

459
00:22:46,960 --> 00:22:50,080
Speaker 1: the electrons for ways to differentiate themselves, so you can

460
00:22:50,119 --> 00:22:52,160
Speaker 1: have two in the first one, and then I don't

461
00:22:52,200 --> 00:22:54,000
Speaker 1: even remember the numbers, and I'm not going to guess,

462
00:22:54,160 --> 00:22:56,399
Speaker 1: but yeah, it gets very complicated. But there are quantum

463
00:22:56,400 --> 00:22:59,600
Speaker 1: mechanical answers for why there are a certain number of

464
00:22:59,640 --> 00:23:02,600
Speaker 1: electors allowed in each shell, as to do with the

465
00:23:02,640 --> 00:23:06,200
Speaker 1: polyexclusion principle and the number of ways you can distribute

466
00:23:06,240 --> 00:23:08,960
Speaker 1: the angular momentum solutions in each energy level.

467
00:23:09,640 --> 00:23:12,760
Speaker 2: In my head, at some point the number of electrons

468
00:23:12,800 --> 00:23:15,720
Speaker 2: in the shells as you added shells started being the same.

469
00:23:16,440 --> 00:23:18,960
Speaker 2: But I took chemistry when I was gosh, that was

470
00:23:19,000 --> 00:23:22,120
Speaker 2: over thirty years ago, now, so that's just a bad memory, right.

471
00:23:22,200 --> 00:23:25,560
Speaker 2: It's the number of electrons in each shell gets progressively

472
00:23:26,000 --> 00:23:28,000
Speaker 2: higher the farther you get from the center.

473
00:23:28,640 --> 00:23:32,159
Speaker 1: Yeah, okay, all right, but the shells then start overlapping,

474
00:23:32,200 --> 00:23:36,040
Speaker 1: and you know sometimes like the highest energy subshell from

475
00:23:36,200 --> 00:23:40,280
Speaker 1: level four is actually higher energy than the lowest energy

476
00:23:40,400 --> 00:23:43,600
Speaker 1: subshell from level five. So level five fills up before

477
00:23:43,600 --> 00:23:46,520
Speaker 1: the last level four fills up, and the ordering starts

478
00:23:46,520 --> 00:23:49,560
Speaker 1: to get really, really nasty, which is why electron configurations

479
00:23:49,560 --> 00:23:50,399
Speaker 1: are hard.

480
00:23:50,560 --> 00:23:55,080
Speaker 2: I'm feeling angry. Why is it like that? All right?

481
00:23:55,119 --> 00:23:59,479
Speaker 2: All right, let's give ourselves a chance to release the anger,

482
00:23:59,840 --> 00:24:02,640
Speaker 2: and when we get back from this commercial break, we'll

483
00:24:02,640 --> 00:24:04,760
Speaker 2: take up another peek at the periodic table and look

484
00:24:04,800 --> 00:24:25,280
Speaker 2: for patterns and melting points and we're back. Okay. So

485
00:24:25,960 --> 00:24:28,320
Speaker 2: at the beginning of the show, we talked about where

486
00:24:28,320 --> 00:24:30,800
Speaker 2: you find electrons, how they fill up the shells, and

487
00:24:30,800 --> 00:24:35,240
Speaker 2: how that impacts bonds between atoms. Now we're going to

488
00:24:35,280 --> 00:24:37,240
Speaker 2: take a look at the periodic table because we're really

489
00:24:37,240 --> 00:24:39,280
Speaker 2: interested in melting points to try to figure out why

490
00:24:39,320 --> 00:24:42,600
Speaker 2: mercury is weird. So let's look for patterns in the

491
00:24:42,600 --> 00:24:45,560
Speaker 2: periodic table to see what we should expect mercury to

492
00:24:45,560 --> 00:24:47,080
Speaker 2: be doing in terms of melting points.

493
00:24:47,320 --> 00:24:49,000
Speaker 1: Yeah, and there's a lot of really interesting stuff to

494
00:24:49,040 --> 00:24:51,199
Speaker 1: dig into here, and a lot of it can be

495
00:24:51,280 --> 00:24:54,760
Speaker 1: explained by chemistry. But mercury sticks out like a sore thumb,

496
00:24:54,840 --> 00:24:56,719
Speaker 1: and so we're going to walk you through a couple

497
00:24:56,800 --> 00:24:59,760
Speaker 1: of the trends that explain what's happening in the periodic table,

498
00:25:00,119 --> 00:25:03,200
Speaker 1: but they can't completely describe mercury, and they're not actually

499
00:25:03,359 --> 00:25:07,040
Speaker 1: enough to make mercury liquid at room temperature. So there's

500
00:25:07,080 --> 00:25:08,800
Speaker 1: a little bit of physics we're going to need at

501
00:25:08,800 --> 00:25:11,159
Speaker 1: the end to give you that complete explanation.

502
00:25:11,359 --> 00:25:12,680
Speaker 2: Chemistry is never enough.

503
00:25:13,840 --> 00:25:17,239
Speaker 1: Chemistry is never enough. So let's keep in mind that

504
00:25:17,280 --> 00:25:21,440
Speaker 1: we're thinking about the electron structure of these elements, whether

505
00:25:21,560 --> 00:25:23,919
Speaker 1: or not for example, they have a filled shell. And

506
00:25:23,960 --> 00:25:27,240
Speaker 1: so let's like walk across the middle of the periodic table.

507
00:25:27,440 --> 00:25:31,199
Speaker 1: So you have sc which is scandium, right, and then

508
00:25:31,240 --> 00:25:33,440
Speaker 1: the next one is titanium, and it goes all the

509
00:25:33,480 --> 00:25:36,560
Speaker 1: way across the copper and then to zinc. And if

510
00:25:36,600 --> 00:25:39,400
Speaker 1: you look at the melting points here, they start pretty high,

511
00:25:39,480 --> 00:25:43,480
Speaker 1: like scandium melts at fifteen hundred celsius, and then they

512
00:25:43,480 --> 00:25:46,600
Speaker 1: go down to zinc, which melts at only four hundred celsius.

513
00:25:46,600 --> 00:25:48,440
Speaker 1: Now that's pretty hot. You don't want to get into

514
00:25:48,480 --> 00:25:50,880
Speaker 1: like a hot tub of zinc. But it's a big difference.

515
00:25:50,880 --> 00:25:53,880
Speaker 1: It's like more than a thousand degrees difference. Why does

516
00:25:53,880 --> 00:25:56,760
Speaker 1: scandium melt at a really high temperature, and zinc melts

517
00:25:56,760 --> 00:26:00,520
Speaker 1: at a really low temperature. Because zinc is the end

518
00:26:00,600 --> 00:26:03,720
Speaker 1: of this chunk of the periodic table, it's completed as shell.

519
00:26:04,119 --> 00:26:06,879
Speaker 1: So zinc has a complete shell, which means it's not

520
00:26:06,960 --> 00:26:09,159
Speaker 1: as likely to bond. It's not as easy for it

521
00:26:09,240 --> 00:26:11,399
Speaker 1: to bond, which is why it has a lower melting

522
00:26:11,440 --> 00:26:13,960
Speaker 1: point than all of its friends next to it, Like

523
00:26:14,040 --> 00:26:17,320
Speaker 1: copper right next door to zinc, has a melting point

524
00:26:17,320 --> 00:26:21,080
Speaker 1: of more than one thousand degrees C, where zinc again

525
00:26:21,200 --> 00:26:24,160
Speaker 1: is just four hundred. And you see the same behavior

526
00:26:24,240 --> 00:26:27,880
Speaker 1: in the next row, silver, which is right next to cadmium.

527
00:26:27,960 --> 00:26:31,280
Speaker 1: Cadmium is just under zinc. Silver has a melting point

528
00:26:31,320 --> 00:26:34,480
Speaker 1: of about one thousand C and cadmium of about three hundred.

529
00:26:34,920 --> 00:26:37,520
Speaker 1: So just this one step over you add one proton

530
00:26:37,600 --> 00:26:41,840
Speaker 1: and one electron, melting point drops precipitously, and the reason

531
00:26:42,000 --> 00:26:44,679
Speaker 1: is that you filled up this shell. Now, these atoms

532
00:26:44,720 --> 00:26:46,960
Speaker 1: can form the same kind of strong bonds where they're

533
00:26:46,960 --> 00:26:49,920
Speaker 1: sharing electrons with each other, and so it's much easier

534
00:26:49,920 --> 00:26:52,840
Speaker 1: to break them apart. So that's why zinc and cadmium

535
00:26:52,880 --> 00:26:55,920
Speaker 1: and mercury, which is also in this column have much

536
00:26:56,040 --> 00:27:00,280
Speaker 1: lower melting points than their friends copper, silver, and gold,

537
00:27:00,359 --> 00:27:02,639
Speaker 1: which are right next to them in the periodic table.

538
00:27:02,720 --> 00:27:06,000
Speaker 2: They're more stable, and because they're more stable, it's easier

539
00:27:06,000 --> 00:27:06,840
Speaker 2: to make them liquid.

540
00:27:07,200 --> 00:27:09,920
Speaker 1: It's easier to make them liquid because their bonds are weaker.

541
00:27:10,160 --> 00:27:13,040
Speaker 1: It's not about the stability. These aren't like radioactive elements.

542
00:27:13,240 --> 00:27:15,719
Speaker 1: It's just like do they like to click together? And

543
00:27:15,960 --> 00:27:20,200
Speaker 1: zinc and cadmium and mercury all have a completed last shell.

544
00:27:20,240 --> 00:27:22,320
Speaker 1: It's the S two, the four S two, the five

545
00:27:22,440 --> 00:27:25,199
Speaker 1: S two, or the six S two. They've completed that

546
00:27:25,240 --> 00:27:28,200
Speaker 1: little subshell, and so it's harder for them to form

547
00:27:28,240 --> 00:27:31,440
Speaker 1: bonds like copper and silver and gold. The ones next

548
00:27:31,480 --> 00:27:34,400
Speaker 1: door to them are missing one electron relative to our

549
00:27:34,440 --> 00:27:38,560
Speaker 1: friends zinc, cadmium, and mercury. So they'd like to fill

550
00:27:38,600 --> 00:27:40,800
Speaker 1: in that last shell. And if they meet another atom

551
00:27:40,840 --> 00:27:43,520
Speaker 1: of their type, like two silver come together, they can

552
00:27:43,560 --> 00:27:46,000
Speaker 1: complete that last shell together, and so they can form

553
00:27:46,080 --> 00:27:49,000
Speaker 1: this kind of strong bond by sharing electrons. It's harder

554
00:27:49,040 --> 00:27:52,400
Speaker 1: to break them apart. Mercury can't do that, cadmium can't

555
00:27:52,440 --> 00:27:54,920
Speaker 1: do that, Zinc can't do that, so they can form

556
00:27:54,960 --> 00:27:57,919
Speaker 1: the same kind of strong bond between the atoms, and

557
00:27:57,960 --> 00:28:00,200
Speaker 1: so it's easier to break them apart, which means means

558
00:28:00,280 --> 00:28:01,359
Speaker 1: a lower melting point.

559
00:28:01,680 --> 00:28:02,960
Speaker 2: Got it, okay, thank you.

560
00:28:03,359 --> 00:28:06,600
Speaker 1: So now we're comparing these two columns, right, Column eleven

561
00:28:06,720 --> 00:28:10,280
Speaker 1: has a higher melting point than column twelve zinc, cadmium,

562
00:28:10,280 --> 00:28:14,159
Speaker 1: and mercury. But still, mercury looks weird. Like zinc and

563
00:28:14,240 --> 00:28:17,439
Speaker 1: cadmium melt at three hundred four hundred seeds, it seems

564
00:28:17,440 --> 00:28:20,760
Speaker 1: like a very respectable temperature for a metal. Mercury melts

565
00:28:20,760 --> 00:28:24,840
Speaker 1: at negative thirty nine c like, mercury has a crazy

566
00:28:24,960 --> 00:28:27,680
Speaker 1: low melting point. Right. To make mercury solid, you have

567
00:28:27,760 --> 00:28:31,240
Speaker 1: to get it to negative thirty nine celsius. That's very

568
00:28:31,400 --> 00:28:34,560
Speaker 1: very cold, right, and it's a huge jump. And if

569
00:28:34,560 --> 00:28:36,880
Speaker 1: you're saying, all right, well, this column is all colder

570
00:28:36,880 --> 00:28:40,320
Speaker 1: than the other one. Still within the column, zinc and

571
00:28:40,360 --> 00:28:43,239
Speaker 1: cadmium have a higher melting point than mercury. So what

572
00:28:43,320 --> 00:28:47,280
Speaker 1: makes mercury so much lower than zinc and cadmium. Well,

573
00:28:47,280 --> 00:28:49,600
Speaker 1: there is a trend there that we would expect. As

574
00:28:49,600 --> 00:28:52,560
Speaker 1: you go from top to bottom in the column, you're

575
00:28:52,600 --> 00:28:56,320
Speaker 1: getting heavier and heavier nuclei, right, Like, mercury has more

576
00:28:56,400 --> 00:29:00,560
Speaker 1: protons than cadmium, which is more protons than zinc. And

577
00:29:00,600 --> 00:29:03,840
Speaker 1: that's the other effect we talked about. Mercury holds on

578
00:29:03,960 --> 00:29:07,040
Speaker 1: to its electrons more tightly than cadmium or zinc because

579
00:29:07,040 --> 00:29:10,760
Speaker 1: it has more protons. Say you're an electron floating around

580
00:29:10,840 --> 00:29:14,880
Speaker 1: the atom, there are more protons pulling you in, binding

581
00:29:14,920 --> 00:29:18,160
Speaker 1: you tightly to that atom if you're mercury than if

582
00:29:18,200 --> 00:29:20,680
Speaker 1: your cadmium or if you're zinc. Does that make sense

583
00:29:21,000 --> 00:29:21,360
Speaker 1: kind of?

584
00:29:21,440 --> 00:29:25,560
Speaker 2: So if your mercury, though, you also have more electron shells,

585
00:29:25,680 --> 00:29:28,840
Speaker 2: and so your outer shell, which would do the bonding,

586
00:29:29,000 --> 00:29:33,480
Speaker 2: is farther away from your heavy nucleus. They're farther away.

587
00:29:33,600 --> 00:29:34,160
Speaker 2: What does that do?

588
00:29:35,960 --> 00:29:38,880
Speaker 1: Yes, exactly. And this is my frustration with chemistry is

589
00:29:38,880 --> 00:29:41,040
Speaker 1: that you can often tell your cells these intuitive stories

590
00:29:41,080 --> 00:29:43,760
Speaker 1: and then somebody can come along with another intuitive sounding

591
00:29:43,760 --> 00:29:46,040
Speaker 1: story that also makes sense, and you're like, huh hmmm,

592
00:29:46,280 --> 00:29:48,800
Speaker 1: I don't know which one it is is right, you know,

593
00:29:48,880 --> 00:29:51,720
Speaker 1: And the answer is that it's complicated. But overall the

594
00:29:51,720 --> 00:29:54,400
Speaker 1: fact that they have more protons wins, and so it

595
00:29:54,480 --> 00:29:56,800
Speaker 1: pulls these things in and you know, the way to

596
00:29:56,800 --> 00:29:58,840
Speaker 1: think about it is like, yeah, these things can all

597
00:29:58,880 --> 00:30:01,760
Speaker 1: be neutral. You have an equal number of protons and electrons,

598
00:30:02,280 --> 00:30:04,040
Speaker 1: and the electrons don't like to be on top of

599
00:30:04,040 --> 00:30:06,720
Speaker 1: each other. But still, these protons are very powerful and

600
00:30:06,800 --> 00:30:09,920
Speaker 1: pulling them in, and each electron is having basically just

601
00:30:09,960 --> 00:30:12,880
Speaker 1: a relationship with the protons, not with the other electrons.

602
00:30:13,240 --> 00:30:15,920
Speaker 1: It's not like the power those protons is shielded by

603
00:30:15,960 --> 00:30:21,160
Speaker 1: the other electrons. Instead it's now pulled in by eighty protons. Right,

604
00:30:21,200 --> 00:30:23,880
Speaker 1: So it's a very powerful force. I think that one wins.

605
00:30:23,920 --> 00:30:26,640
Speaker 1: But hey, chemistry experts out there right in and tell

606
00:30:26,680 --> 00:30:27,600
Speaker 1: me if we got that wrong.

607
00:30:28,160 --> 00:30:31,560
Speaker 2: Okay, so mercury really wants to be a liquid, and

608
00:30:31,800 --> 00:30:34,800
Speaker 2: we know that because it has a full shell and

609
00:30:34,880 --> 00:30:41,040
Speaker 2: it's really big. But even knowing those two things, mercury

610
00:30:41,080 --> 00:30:45,240
Speaker 2: wants to be a liquid at temperatures way lower than

611
00:30:45,280 --> 00:30:47,920
Speaker 2: what we would have expected. So where do we go

612
00:30:47,960 --> 00:30:49,120
Speaker 2: next to try to understand that.

613
00:30:49,440 --> 00:30:51,720
Speaker 1: Yes, so we're at the limits of chemistry here. Chemistry

614
00:30:51,720 --> 00:30:55,480
Speaker 1: tells us yes, mercury should be lower than gold, for example,

615
00:30:55,480 --> 00:30:57,760
Speaker 1: in the same way zinc should be lower than copper,

616
00:30:58,000 --> 00:31:01,400
Speaker 1: and it is, and chemistry tells yes, mercury should have

617
00:31:01,400 --> 00:31:04,080
Speaker 1: a lower melting point than cadmium or zinc because there's

618
00:31:04,080 --> 00:31:06,160
Speaker 1: a bigger atom and it holds these things in and

619
00:31:06,200 --> 00:31:08,600
Speaker 1: that's all cool. But if you run the calculations and

620
00:31:08,600 --> 00:31:12,280
Speaker 1: you take all that into account, chemistry predicts that mercury's

621
00:31:12,320 --> 00:31:15,640
Speaker 1: melting point should be eighty two C, but the measured

622
00:31:15,720 --> 00:31:19,200
Speaker 1: value is negative thirty nine. See more than one hundred differents.

623
00:31:19,320 --> 00:31:22,120
Speaker 1: So like, yes, there are these trends that suggest mercury

624
00:31:22,160 --> 00:31:24,840
Speaker 1: should have a low melting point, but they suggest it

625
00:31:24,840 --> 00:31:28,320
Speaker 1: should still be solid at room temperature. To get mercury

626
00:31:28,520 --> 00:31:31,560
Speaker 1: even lower, To get that melting point down below room

627
00:31:31,600 --> 00:31:34,280
Speaker 1: temp and even down below zero C, you need to

628
00:31:34,320 --> 00:31:38,400
Speaker 1: do something else. Chemistry is not enough to make mercury liquid.

629
00:31:38,720 --> 00:31:41,640
Speaker 2: On chemistry, get better with your predictions. This isn't physics.

630
00:31:43,440 --> 00:31:45,520
Speaker 1: So you might think, well, it is quantum mechanics wrong,

631
00:31:45,640 --> 00:31:48,440
Speaker 1: because chemistry is determined by quantum mechanics. We just told

632
00:31:48,440 --> 00:31:50,680
Speaker 1: you about all the shells and the shortening their equation

633
00:31:50,760 --> 00:31:54,000
Speaker 1: and all this stuff, right, So is quantum mechanics wrong. Well,

634
00:31:54,080 --> 00:31:56,800
Speaker 1: quantum mechanics by itself is not wrong, but it's not

635
00:31:56,880 --> 00:31:59,920
Speaker 1: the whole story. Right. We know that quantum mechanics doesn't

636
00:32:00,000 --> 00:32:02,840
Speaker 1: describe the entire universe. Because quant mechanics, for example, can

637
00:32:02,960 --> 00:32:06,280
Speaker 1: describe gravity, or black holes or the beginning of the universe.

638
00:32:06,520 --> 00:32:10,240
Speaker 1: We have another theory in physics that helps us explain

639
00:32:10,320 --> 00:32:12,440
Speaker 1: what happens when things get really really fast or when

640
00:32:12,480 --> 00:32:16,640
Speaker 1: things get really really massive. That's relativity. All the calculations

641
00:32:16,680 --> 00:32:19,320
Speaker 1: we've been doing, all the explanations we've been giving are

642
00:32:19,680 --> 00:32:22,880
Speaker 1: chemistry based on quantum mechanics that assumes that relativity is

643
00:32:22,920 --> 00:32:25,880
Speaker 1: not a thing. If, for example, assumes that there's no

644
00:32:26,000 --> 00:32:28,440
Speaker 1: limit to how fast things can go, or that there

645
00:32:28,440 --> 00:32:32,000
Speaker 1: are no black holes, we're essentially ignoring relativity and doing

646
00:32:32,080 --> 00:32:35,800
Speaker 1: pure quantum mechanical calculations. And most of the time that's fine.

647
00:32:35,840 --> 00:32:39,160
Speaker 1: Relativity is not really relevant. We're not doing chemistry around

648
00:32:39,160 --> 00:32:41,120
Speaker 1: a black hole. We're not doing chemistry near the speed

649
00:32:41,120 --> 00:32:44,800
Speaker 1: of light. So it works. But you know, sometimes it doesn't.

650
00:32:44,840 --> 00:32:47,120
Speaker 1: And that's what's happening here, is that we've been ignoring

651
00:32:47,160 --> 00:32:51,160
Speaker 1: the relativistic effects on the electrons of mercury.

652
00:32:51,560 --> 00:32:54,880
Speaker 2: And that's because everywhere there's mercury, there's actually a tiny

653
00:32:54,960 --> 00:32:58,680
Speaker 2: black hole next to it. Is that right? No?

654
00:32:58,680 --> 00:33:01,440
Speaker 1: No, okay, though, but you know where you can get

655
00:33:01,440 --> 00:33:02,480
Speaker 1: your mercury at.

656
00:33:02,400 --> 00:33:04,040
Speaker 2: The flea markets.

657
00:33:04,640 --> 00:33:08,880
Speaker 1: No in HG. Wells grown.

658
00:33:11,560 --> 00:33:12,280
Speaker 2: No that was great.

659
00:33:13,160 --> 00:33:16,120
Speaker 1: No it was not great, but thank you anyway. Yeah, So,

660
00:33:16,160 --> 00:33:18,600
Speaker 1: what's happening here is not that there's a black hole

661
00:33:18,760 --> 00:33:21,320
Speaker 1: next to every bit of mercury, although I love the

662
00:33:21,320 --> 00:33:24,000
Speaker 1: theory and if you heard it that maybe every electron

663
00:33:24,040 --> 00:33:26,160
Speaker 1: actually is a black hole and could we tell anyway.

664
00:33:26,520 --> 00:33:28,760
Speaker 1: I love to talk about that on the podcast another time.

665
00:33:28,960 --> 00:33:31,640
Speaker 1: You know, what's happening here is that electrons are actually

666
00:33:31,760 --> 00:33:36,200
Speaker 1: relativistic around mercury. Mercury is so powerful with this nucleus,

667
00:33:36,200 --> 00:33:38,840
Speaker 1: those eighty protons have such a strong hold on the

668
00:33:38,880 --> 00:33:42,960
Speaker 1: electron that the electron velocities start to approach the speed

669
00:33:42,960 --> 00:33:45,240
Speaker 1: of light. They're not going at like ninety nine percent

670
00:33:45,280 --> 00:33:48,800
Speaker 1: the speed of light, but whereas electrons around hydrogen go

671
00:33:48,840 --> 00:33:51,640
Speaker 1: about one percent of the speed of light, electrons near

672
00:33:51,680 --> 00:33:54,840
Speaker 1: mercury move almost sixty percent of the speed of light,

673
00:33:54,880 --> 00:33:58,240
Speaker 1: which is close enough for these relativistic effects to start

674
00:33:58,280 --> 00:33:58,720
Speaker 1: to matter.

675
00:33:59,040 --> 00:34:02,720
Speaker 2: So that suggest to me then that everything with eighty

676
00:34:02,760 --> 00:34:07,400
Speaker 2: protons are more should also have these relativistic effects. Is

677
00:34:07,440 --> 00:34:09,520
Speaker 2: that true? From there on out, we need relativity to

678
00:34:09,600 --> 00:34:11,920
Speaker 2: understand the melting points of atoms.

679
00:34:12,239 --> 00:34:15,719
Speaker 1: Yes, absolutely. And there's another guy under mercury in the

680
00:34:15,719 --> 00:34:19,840
Speaker 1: periodic table, copronicsium, which is a crazy synthetic chemical element,

681
00:34:20,239 --> 00:34:21,880
Speaker 1: which means we need to make it. It's not like

682
00:34:21,960 --> 00:34:24,960
Speaker 1: found naturally in the wild, and people suspect that the

683
00:34:24,960 --> 00:34:28,760
Speaker 1: relativistic effects for copronicsium are even stronger than from mercury.

684
00:34:28,840 --> 00:34:31,080
Speaker 1: Mercury is something that's all over the place, so it's

685
00:34:31,080 --> 00:34:33,879
Speaker 1: well studied and easy to play with. But turns out

686
00:34:33,920 --> 00:34:37,759
Speaker 1: doing these calculations, including the relativity in our calculations, is

687
00:34:37,920 --> 00:34:40,840
Speaker 1: very hard, which is one reason why only a couple

688
00:34:40,840 --> 00:34:43,400
Speaker 1: of years ago were people able to do this calculation

689
00:34:43,480 --> 00:34:48,680
Speaker 1: and predict the relativistic corrections to the original quantum mechanical calculations.

690
00:34:49,000 --> 00:34:52,400
Speaker 2: Say that again, this time in English.

691
00:34:52,440 --> 00:34:54,279
Speaker 1: So you can go out and measure the melting point

692
00:34:54,280 --> 00:34:56,120
Speaker 1: of mercury, right, you put it on the table, you

693
00:34:56,200 --> 00:34:58,000
Speaker 1: heat it up, you see it melt, you cool it down,

694
00:34:58,080 --> 00:35:01,480
Speaker 1: you see it solidify. That's the measure value. Then you

695
00:35:01,520 --> 00:35:03,799
Speaker 1: can go and say, I'm going to predict what it

696
00:35:03,840 --> 00:35:06,680
Speaker 1: should be based on my understanding of what's happening. And

697
00:35:06,719 --> 00:35:09,440
Speaker 1: they can do calculations, and they do these calculations like

698
00:35:09,480 --> 00:35:12,120
Speaker 1: we referenced earlier on number of eighty two c that

699
00:35:12,200 --> 00:35:14,800
Speaker 1: comes from using quantum mechanics to predict the strength of

700
00:35:14,840 --> 00:35:17,839
Speaker 1: these bonds and understanding like at what temperature those bonds

701
00:35:17,840 --> 00:35:20,640
Speaker 1: would break. So you're using quantum mechanics to predict the

702
00:35:20,640 --> 00:35:22,440
Speaker 1: bonds and from that you can get the temperature. So

703
00:35:22,440 --> 00:35:25,840
Speaker 1: that's the predicted value of mercury. Now, if you go

704
00:35:25,880 --> 00:35:27,640
Speaker 1: in you say, well, I'm going to tweak quantum mechanics

705
00:35:27,680 --> 00:35:30,040
Speaker 1: because I'm going to do quantum mechanics not by itself.

706
00:35:30,080 --> 00:35:33,440
Speaker 1: I'm going to include relativistic effects in my quantum mechanics.

707
00:35:33,760 --> 00:35:37,520
Speaker 1: Then you're changing what's going on in your predicted mercury,

708
00:35:37,760 --> 00:35:40,880
Speaker 1: which changes the prediction of the bonds, which changes your

709
00:35:40,880 --> 00:35:44,719
Speaker 1: prediction for the melting point. And so when we see

710
00:35:44,719 --> 00:35:47,480
Speaker 1: a difference between our prediction and our observation, we know

711
00:35:47,560 --> 00:35:49,759
Speaker 1: something is wrong. So we go back and tweak our

712
00:35:49,760 --> 00:35:52,560
Speaker 1: predictions to make it right. And you know, in principle

713
00:35:52,600 --> 00:35:55,040
Speaker 1: we should always be using relativity to get everything right.

714
00:35:55,080 --> 00:35:57,040
Speaker 1: But most of the time it's irrelevant. You want to

715
00:35:57,080 --> 00:35:59,400
Speaker 1: calculate when the train is going to go from Cleveland

716
00:35:59,440 --> 00:36:02,000
Speaker 1: to New York. Relativity doesn't have any impact, right, so

717
00:36:02,040 --> 00:36:04,960
Speaker 1: you can ignore it. Also, relativity is a huge pain, like,

718
00:36:05,040 --> 00:36:07,680
Speaker 1: it's non linear, it's complicated, it's not easy to do.

719
00:36:07,760 --> 00:36:09,799
Speaker 1: So most of the time, if you can't ignore it,

720
00:36:09,880 --> 00:36:13,520
Speaker 1: you should. But when you discover that your non relativistic

721
00:36:13,520 --> 00:36:15,799
Speaker 1: calculations are not up to the task, when they're getting

722
00:36:15,800 --> 00:36:18,080
Speaker 1: me answer wrong, that's when you've got to go back

723
00:36:18,120 --> 00:36:21,960
Speaker 1: and do your homework and include the physics in your calculation,

724
00:36:22,560 --> 00:36:25,160
Speaker 1: because it turns out it's necessary beautiful.

725
00:36:25,239 --> 00:36:28,120
Speaker 2: Okay, all right, So now we've got electrons moving super

726
00:36:28,160 --> 00:36:32,400
Speaker 2: fast and now we're incorporating relativity. What is the jump

727
00:36:32,400 --> 00:36:36,320
Speaker 2: from there to understanding why melting point is affected?

728
00:36:36,800 --> 00:36:40,200
Speaker 1: Yeah, so first we should clarify which part of relativity

729
00:36:40,200 --> 00:36:43,640
Speaker 1: we're including, because folks, everythinking Daniel's been telling us that

730
00:36:43,719 --> 00:36:47,000
Speaker 1: quantum mechanics and relativity can't play nice together, like that's

731
00:36:47,040 --> 00:36:49,480
Speaker 1: the whole goal of modern physics has come up with

732
00:36:49,560 --> 00:36:51,759
Speaker 1: quantum gravity and understanding the early universe and blah blah

733
00:36:51,800 --> 00:36:52,560
Speaker 1: blah and string theory.

734
00:36:52,640 --> 00:36:54,319
Speaker 2: That's right, Daniel has been telling us that.

735
00:36:56,000 --> 00:36:58,320
Speaker 1: And that was not a load of baloney. That's all true.

736
00:36:58,800 --> 00:37:01,759
Speaker 1: That refers to our fail to unify quantum mechanics with

737
00:37:01,960 --> 00:37:05,279
Speaker 1: general relativity, the theory of gravity and curvature and all

738
00:37:05,320 --> 00:37:07,560
Speaker 1: sorts of crazy stuff, which we have not been able

739
00:37:07,600 --> 00:37:10,520
Speaker 1: to do. But we have, and it's been decades and

740
00:37:10,560 --> 00:37:14,799
Speaker 1: decades since we've done this. Unified quantum mechanics and special relativity,

741
00:37:15,040 --> 00:37:17,160
Speaker 1: the theory of what happens when things go near the

742
00:37:17,160 --> 00:37:19,319
Speaker 1: speed of light and incorporates the fact that light is

743
00:37:19,360 --> 00:37:21,759
Speaker 1: always the same for all observers and that nothing can

744
00:37:21,800 --> 00:37:25,360
Speaker 1: go faster than light. Special relativity, which is just like

745
00:37:25,520 --> 00:37:28,680
Speaker 1: flat space, but includes things like time dilation and length

746
00:37:28,719 --> 00:37:32,600
Speaker 1: contraction and maximum speeds and weird velocities and stuff. That's

747
00:37:32,600 --> 00:37:35,160
Speaker 1: special relativity that we have been able to merge with

748
00:37:35,320 --> 00:37:39,640
Speaker 1: quantum mechanics. We have relativistic quantum mechanics that allows us

749
00:37:39,640 --> 00:37:42,600
Speaker 1: to do these calculations, or quantum field theory also has

750
00:37:42,680 --> 00:37:46,440
Speaker 1: special relativity built in. So special relativity and quantum mechanics

751
00:37:46,480 --> 00:37:48,080
Speaker 1: do play very nicely together.

752
00:37:48,480 --> 00:37:53,440
Speaker 2: Aw that's great, okay. And so when they're playing together,

753
00:37:54,000 --> 00:37:56,320
Speaker 2: why does them playing together change?

754
00:37:57,239 --> 00:38:00,279
Speaker 1: Yeah? Great question. And since this paper came out, been

755
00:38:00,280 --> 00:38:02,720
Speaker 1: a lot of coverage of this result in popular media,

756
00:38:03,080 --> 00:38:06,000
Speaker 1: and I read all of them, and they're all wrong.

757
00:38:06,400 --> 00:38:08,440
Speaker 1: What they all get the physics wrong.

758
00:38:09,960 --> 00:38:12,120
Speaker 2: Let's take a break, and when we come back, you're

759
00:38:12,120 --> 00:38:31,280
Speaker 2: gonna tell us how we get it right. Before the break,

760
00:38:31,640 --> 00:38:33,640
Speaker 2: Daniel was telling us that he's been reading a bunch

761
00:38:33,640 --> 00:38:36,640
Speaker 2: of popsye articles that attempt to merge quantum mechanics and

762
00:38:36,719 --> 00:38:40,960
Speaker 2: special relativity and that all of their explanations are wrong.

763
00:38:41,160 --> 00:38:43,239
Speaker 2: So let's talk about the wrong explanations first.

764
00:38:43,360 --> 00:38:46,279
Speaker 1: Yeah, and these are not just popsye articles in like,

765
00:38:46,719 --> 00:38:49,360
Speaker 1: you know, science News, dot buzz or something.

766
00:38:49,600 --> 00:38:50,400
Speaker 2: I hate science.

767
00:38:53,040 --> 00:38:55,720
Speaker 1: People are constantly boarding me articles from sites with names

768
00:38:55,719 --> 00:38:58,080
Speaker 1: like that and being like is this true? And I'm like, man,

769
00:38:58,120 --> 00:38:59,799
Speaker 1: why are you gonna read in that site? You know?

770
00:39:00,360 --> 00:39:02,960
Speaker 1: But there's some pretty venerable places that have put out

771
00:39:03,000 --> 00:39:05,920
Speaker 1: press releases and articles about this that get it wrong,

772
00:39:06,560 --> 00:39:09,480
Speaker 1: and they all repeat the same nonsense. They all repeat

773
00:39:09,520 --> 00:39:12,840
Speaker 1: this business about how electrons, when they approach the speed

774
00:39:12,840 --> 00:39:17,279
Speaker 1: of light, gain mass become more massive. That's the heart

775
00:39:17,320 --> 00:39:23,000
Speaker 1: of their explanation. And number one, that's not true. Things

776
00:39:23,080 --> 00:39:25,759
Speaker 1: do not gain mass as they approach the speed of light.

777
00:39:26,120 --> 00:39:29,799
Speaker 1: This concept of relativistic mass is outdated, it's not appropriate.

778
00:39:29,920 --> 00:39:32,160
Speaker 1: It was Einstein's mistake. We talked about it recently on

779
00:39:32,200 --> 00:39:35,120
Speaker 1: the podcast. We can dig in it again in a moment. Also,

780
00:39:35,480 --> 00:39:40,240
Speaker 1: it doesn't really explain why mercury has a lower melting point,

781
00:39:40,480 --> 00:39:43,320
Speaker 1: you know, electrons having more mass doesn't answer this question.

782
00:39:43,840 --> 00:39:46,920
Speaker 1: I actually reached out to a chemist here at UCI

783
00:39:47,080 --> 00:39:51,120
Speaker 1: to ask him about this, and he said, quote, most

784
00:39:51,239 --> 00:39:54,399
Speaker 1: chemists know little about relativity, and I suspect that makes

785
00:39:54,440 --> 00:39:57,040
Speaker 1: them more likely to swallow the pop side buzzwords.

786
00:39:57,440 --> 00:39:59,680
Speaker 2: Oh, I'm surprised any chemist was willing to talk to

787
00:39:59,719 --> 00:40:02,240
Speaker 2: e given our reputations.

788
00:40:03,280 --> 00:40:06,120
Speaker 1: Well, maybe he's not a listener to the podcast. So

789
00:40:06,200 --> 00:40:08,080
Speaker 1: let's unpack that for a minute. Why do I say

790
00:40:08,160 --> 00:40:10,759
Speaker 1: that it's not true that electrons increase their mass because

791
00:40:10,760 --> 00:40:13,640
Speaker 1: you hear that everywhere, right, And it's a very popular

792
00:40:13,680 --> 00:40:16,560
Speaker 1: thing to say because it sounds weird. It's one of

793
00:40:16,560 --> 00:40:18,799
Speaker 1: these things that people say a lot because that has

794
00:40:18,840 --> 00:40:21,280
Speaker 1: an impact on your mind. But it doesn't really actually

795
00:40:21,360 --> 00:40:24,600
Speaker 1: make sense. It just sounds cool. And we talked about

796
00:40:24,640 --> 00:40:26,960
Speaker 1: on the podcast why that doesn't really make sense and

797
00:40:27,000 --> 00:40:30,520
Speaker 1: why relativistic mass isn't even a useful concept. It doesn't

798
00:40:30,520 --> 00:40:33,880
Speaker 1: make sense because if mass depends on velocity. Velocity is

799
00:40:33,920 --> 00:40:36,960
Speaker 1: three directions, right, it's a vector. You can velocity in

800
00:40:37,000 --> 00:40:40,080
Speaker 1: one direction, another direction, a third direction. There's three dimensions

801
00:40:40,120 --> 00:40:44,080
Speaker 1: of space. If three dimensions of velocity. If mass depends

802
00:40:44,120 --> 00:40:47,600
Speaker 1: on velocity, then mass also has three dimensions. Then you

803
00:40:47,600 --> 00:40:50,680
Speaker 1: would have like a different mass in each direction. It's weird,

804
00:40:50,800 --> 00:40:52,719
Speaker 1: it doesn't make any sense. It's not what we think

805
00:40:52,719 --> 00:40:56,759
Speaker 1: about as mass, and mostly it's misleading people think that

806
00:40:56,880 --> 00:40:59,800
Speaker 1: something weird and mystical is happening, like as the electron

807
00:40:59,840 --> 00:41:02,600
Speaker 1: is a approaching the speed of light, it's growing and

808
00:41:02,640 --> 00:41:04,799
Speaker 1: mass like it's getting more stuffed to it in some

809
00:41:04,920 --> 00:41:08,360
Speaker 1: weird way. That's not what's happening at all. What's happening

810
00:41:08,400 --> 00:41:11,359
Speaker 1: instead is that as electrons approach the speed of light

811
00:41:11,400 --> 00:41:15,520
Speaker 1: relative to an object, our intuition about the relationship between

812
00:41:15,680 --> 00:41:20,320
Speaker 1: energy and velocity fails down here at very low velocity

813
00:41:20,360 --> 00:41:22,600
Speaker 1: is the surface of the Earth. When we're running around

814
00:41:22,640 --> 00:41:25,000
Speaker 1: at low speeds and driving, and what we think our

815
00:41:25,080 --> 00:41:27,400
Speaker 1: high speeds were really pretty slow compared to the speed

816
00:41:27,400 --> 00:41:30,600
Speaker 1: of light. We think that as you add energy, velocity

817
00:41:30,640 --> 00:41:33,360
Speaker 1: goes up to and they go up together, right, But

818
00:41:33,440 --> 00:41:35,279
Speaker 1: what happens as you approach the speed of light is

819
00:41:35,480 --> 00:41:38,040
Speaker 1: energy can keep going up. There's no limit to energy,

820
00:41:38,320 --> 00:41:40,719
Speaker 1: but a velocity is limited to the speed of light,

821
00:41:40,800 --> 00:41:43,760
Speaker 1: and so as you add energy to something, it's velocity

822
00:41:43,880 --> 00:41:47,160
Speaker 1: doesn't go up by as much, and so that sounds

823
00:41:47,200 --> 00:41:49,680
Speaker 1: sort of like, oh, it's getting more massive because it's

824
00:41:49,719 --> 00:41:52,800
Speaker 1: harder to get it to go faster. Right, It's really

825
00:41:52,880 --> 00:41:55,480
Speaker 1: just a relationship between velocity and energy that gets more

826
00:41:55,480 --> 00:41:57,880
Speaker 1: complicated near the speed of light. So it's not like

827
00:41:58,160 --> 00:42:01,960
Speaker 1: a useful things we can use energy. Energy contains all

828
00:42:01,960 --> 00:42:05,400
Speaker 1: the same information as relativistic mass, and energy is not

829
00:42:05,440 --> 00:42:07,640
Speaker 1: as misleading. It doesn't give people the impression that, like

830
00:42:07,640 --> 00:42:10,560
Speaker 1: the electrons getting more stuff to it somehow, So it's

831
00:42:10,560 --> 00:42:13,279
Speaker 1: not a useful concept and it's misleading. And in this case,

832
00:42:13,360 --> 00:42:18,440
Speaker 1: it doesn't explain why mercury would have a lower melting point.

833
00:42:18,920 --> 00:42:22,399
Speaker 1: You know, having more mass would mean it would take

834
00:42:22,520 --> 00:42:25,839
Speaker 1: more energy to get you to higher velocities. But these

835
00:42:25,880 --> 00:42:29,120
Speaker 1: things are moving at very very high velocities, so that

836
00:42:29,160 --> 00:42:31,759
Speaker 1: would imply that they have even more energy, which would

837
00:42:31,760 --> 00:42:34,759
Speaker 1: push them out from the center and would be easier

838
00:42:35,120 --> 00:42:38,040
Speaker 1: for them to nab by other atoms. And so it

839
00:42:38,080 --> 00:42:40,319
Speaker 1: sort of goes in the wrong direction as far as

840
00:42:40,320 --> 00:42:41,400
Speaker 1: I understand.

841
00:42:41,000 --> 00:42:43,040
Speaker 2: It, all right, so I am definitely not going to

842
00:42:43,040 --> 00:42:45,960
Speaker 2: be reading science dot buzz or what was it, science

843
00:42:46,040 --> 00:42:49,680
Speaker 2: News dot bus because they clearly got this wrong. And

844
00:42:49,719 --> 00:42:51,600
Speaker 2: you know, you mentioned that everybody was talking about it,

845
00:42:51,640 --> 00:42:53,400
Speaker 2: and you know when my daughter came home from school

846
00:42:53,440 --> 00:42:55,880
Speaker 2: and was like, electrons increase their mass as they approached

847
00:42:55,920 --> 00:42:58,320
Speaker 2: the speed of light, I was like, I'm so disappointed

848
00:42:58,360 --> 00:43:00,600
Speaker 2: in you, Ada, But so what is the right explanation?

849
00:43:02,760 --> 00:43:06,120
Speaker 1: So there is an explanation. It's not like as simple

850
00:43:06,280 --> 00:43:10,040
Speaker 1: and as compact a story. As the electron gets weirdly massive.

851
00:43:10,719 --> 00:43:13,920
Speaker 1: The answer is that to figure out where the electrons go,

852
00:43:14,120 --> 00:43:16,640
Speaker 1: you have to solve the equations, and the equations depend

853
00:43:16,680 --> 00:43:20,160
Speaker 1: on a lot of stuff, and the solutions to those equations,

854
00:43:20,160 --> 00:43:22,560
Speaker 1: you know, the energies that the electrons are happy to

855
00:43:22,560 --> 00:43:25,839
Speaker 1: be at are different if you include relativity than if

856
00:43:25,840 --> 00:43:29,319
Speaker 1: you don't. And if you include relativity, you get electrons

857
00:43:29,360 --> 00:43:32,480
Speaker 1: with smaller orbits. Right, they're still moving at very very

858
00:43:32,520 --> 00:43:38,120
Speaker 1: high speeds, but they have tighter orbits. They're closer to mercury. Essentially,

859
00:43:38,160 --> 00:43:42,239
Speaker 1: they have lower energy than without relativity, and so they

860
00:43:42,239 --> 00:43:45,880
Speaker 1: have tighter orbits at these very high velocities, and because

861
00:43:45,880 --> 00:43:48,560
Speaker 1: they have tighter orbits, mercury is able to hold on

862
00:43:48,640 --> 00:43:52,040
Speaker 1: to these electrons even more tightly than its friends in

863
00:43:52,080 --> 00:43:55,440
Speaker 1: the same column zinc and cadmium, for example. And so

864
00:43:55,480 --> 00:43:58,720
Speaker 1: if you turn off relativity, then it relaxes a little

865
00:43:58,719 --> 00:44:02,319
Speaker 1: bit and these electron get larger. If you turn on relativity,

866
00:44:02,520 --> 00:44:05,200
Speaker 1: then the electron orbitals shrink a little bit. And I

867
00:44:05,239 --> 00:44:07,000
Speaker 1: went back to that chemist and I asked him, hey,

868
00:44:07,000 --> 00:44:09,759
Speaker 1: do you have an intuitive explanation for what's going on here?

869
00:44:10,040 --> 00:44:12,600
Speaker 1: Is there a nice little story in the same vein

870
00:44:12,680 --> 00:44:15,520
Speaker 1: as like, hey, electrons get more mass, but actually correct?

871
00:44:17,040 --> 00:44:19,279
Speaker 1: And he said, look, chemistry is complicated. The answer is no,

872
00:44:19,320 --> 00:44:21,640
Speaker 1: there isn't a nice simple explanation. It's just that when

873
00:44:21,680 --> 00:44:25,120
Speaker 1: you include these effects, the first order relativistic correction if

874
00:44:25,120 --> 00:44:28,600
Speaker 1: you're doing perturbation theory, is to reduce the energy of

875
00:44:28,640 --> 00:44:30,960
Speaker 1: this shell. And it turns out to be a really

876
00:44:31,040 --> 00:44:34,360
Speaker 1: hard calculation, which is why people only recently were able

877
00:44:34,400 --> 00:44:36,480
Speaker 1: to do it. You have to model a bunch of

878
00:44:36,520 --> 00:44:39,680
Speaker 1: atoms altogether to figure out the bonds between them and

879
00:44:39,840 --> 00:44:42,719
Speaker 1: all of the electrons around those atoms, and this is

880
00:44:42,719 --> 00:44:45,520
Speaker 1: a really hard thing to do you need really powerful computers?

881
00:44:45,560 --> 00:44:48,560
Speaker 1: And then adding the relativistic pieces means every time you

882
00:44:48,600 --> 00:44:51,200
Speaker 1: want to move your system forward in time, you have

883
00:44:51,320 --> 00:44:54,600
Speaker 1: to do a bunch more complicated calculations. Like relativity makes

884
00:44:54,640 --> 00:44:57,319
Speaker 1: everything harder, Like not only is it harder to think

885
00:44:57,320 --> 00:44:59,440
Speaker 1: about it, but it's also harder to get our computers

886
00:44:59,480 --> 00:45:02,160
Speaker 1: to predict. There's like more steps in each calculation, more

887
00:45:02,400 --> 00:45:05,040
Speaker 1: multiplications and divisions and square roots and all sorts of

888
00:45:05,360 --> 00:45:09,400
Speaker 1: really weird stuff. But it's these relativistic effects which push

889
00:45:09,520 --> 00:45:13,480
Speaker 1: the prediction from chemistry down below room temperature. So there's

890
00:45:13,520 --> 00:45:16,560
Speaker 1: a recent paper and they predict that the melting point

891
00:45:16,600 --> 00:45:19,960
Speaker 1: of mercury should be negative twenty three C. So without

892
00:45:19,960 --> 00:45:23,800
Speaker 1: relativity they predict eighty two c. With relativity, they predict

893
00:45:23,880 --> 00:45:26,640
Speaker 1: negative twenty three c. Now the real value is negative

894
00:45:26,640 --> 00:45:28,719
Speaker 1: thirty nine CE. So they're still not getting it right.

895
00:45:28,760 --> 00:45:32,920
Speaker 1: There's still more to understand there, probably second third order

896
00:45:32,960 --> 00:45:37,840
Speaker 1: relativistic corrections, more detailed, accurate predictions, but they have gotten

897
00:45:37,880 --> 00:45:41,480
Speaker 1: it down below room temperature. And so this we're convinced

898
00:45:41,560 --> 00:45:45,239
Speaker 1: is the explanation for why mercury is a liquid or

899
00:45:45,320 --> 00:45:46,960
Speaker 1: room temperature. It's relativity.

900
00:45:47,239 --> 00:45:51,520
Speaker 2: So that is super cool. So mercury has an atomic

901
00:45:51,600 --> 00:45:55,160
Speaker 2: number of eighty and it's got a really low melting point,

902
00:45:55,800 --> 00:46:00,279
Speaker 2: But why doesn't everything past eighty also have a really

903
00:46:00,280 --> 00:46:02,880
Speaker 2: low melting point. It still feels like mercury isn't all

904
00:46:03,719 --> 00:46:04,799
Speaker 2: relative to everything else.

905
00:46:05,080 --> 00:46:07,600
Speaker 1: Yeah, well it sort of does, like if you keep going.

906
00:46:07,640 --> 00:46:10,160
Speaker 1: You know, lead, for example, has a melting point of

907
00:46:10,160 --> 00:46:12,680
Speaker 1: three hundred and twenty. That's not that high. It's a

908
00:46:12,719 --> 00:46:16,600
Speaker 1: lot lower than silver and gold, and that's because it's

909
00:46:16,640 --> 00:46:19,520
Speaker 1: really heavy and it has these relativistic effects. But also

910
00:46:19,600 --> 00:46:21,960
Speaker 1: it doesn't have a complete shell, so it's much higher

911
00:46:22,000 --> 00:46:23,920
Speaker 1: than mercury because it doesn't have a complete shell. If

912
00:46:23,960 --> 00:46:26,000
Speaker 1: you get all the way over to the end of

913
00:46:26,040 --> 00:46:29,080
Speaker 1: the periodic table, if like xenon, its melting point is

914
00:46:29,120 --> 00:46:33,440
Speaker 1: like negative one hundred C and radon is like negative seventy. See,

915
00:46:33,640 --> 00:46:36,680
Speaker 1: these things are gas at room temperature, so you see

916
00:46:36,719 --> 00:46:39,240
Speaker 1: those effects. As you move down the periodic table, melting

917
00:46:39,239 --> 00:46:42,600
Speaker 1: points are shrinking, and one of these reasons is relativity.

918
00:46:42,920 --> 00:46:44,440
Speaker 1: But it's not the only thing that's.

919
00:46:44,239 --> 00:46:48,360
Speaker 2: Happening, right, Okay, So it's the combination of the shells

920
00:46:48,400 --> 00:46:52,920
Speaker 2: being filled, how tightly those shells are held by the

921
00:46:53,040 --> 00:46:57,880
Speaker 2: nucleus being heavy, and the fact that that heavy nucleus

922
00:46:57,920 --> 00:46:59,719
Speaker 2: is causing the electrons to move faster. Now you have

923
00:46:59,760 --> 00:47:02,000
Speaker 2: really sativistic effects, and all three of those things come

924
00:47:02,040 --> 00:47:05,359
Speaker 2: together with mercury to impact a s melting point more

925
00:47:05,360 --> 00:47:07,080
Speaker 2: than anything else. So like, for example, if you move

926
00:47:07,400 --> 00:47:12,359
Speaker 2: to ten, ten, yes, still has that relativistic effect going on,

927
00:47:12,440 --> 00:47:15,520
Speaker 2: but now you have one electron in the outer shell,

928
00:47:15,920 --> 00:47:18,160
Speaker 2: and so it's wanting to react to stuff, and so

929
00:47:18,200 --> 00:47:20,200
Speaker 2: now you're in a different world altogether, and that's why

930
00:47:20,280 --> 00:47:22,320
Speaker 2: it doesn't have such a low melting point.

931
00:47:22,480 --> 00:47:24,759
Speaker 1: I think maybe you're thinking about thallium, which is the

932
00:47:24,800 --> 00:47:27,200
Speaker 1: next one over for mercury, and it looks like ten

933
00:47:27,400 --> 00:47:32,480
Speaker 1: but it's actually a TL. But otherwise, yes, exactly, yeah,

934
00:47:32,520 --> 00:47:34,840
Speaker 1: And so that's why thallium is like three one hundred

935
00:47:34,840 --> 00:47:38,200
Speaker 1: and fifty degrees higher melting point than mercury, because it's

936
00:47:38,200 --> 00:47:40,840
Speaker 1: got this one extra electron which we're very happy to

937
00:47:40,920 --> 00:47:42,760
Speaker 1: bond with other thallium atoms.

938
00:47:43,160 --> 00:47:46,440
Speaker 2: My annual eye appointment is next week, and so maybe

939
00:47:46,600 --> 00:47:48,080
Speaker 2: in a few weeks I'll be able to read the

940
00:47:48,120 --> 00:47:48,960
Speaker 2: periodic table.

941
00:47:49,080 --> 00:47:51,040
Speaker 1: But even if it was TI, that wouldn't be ten

942
00:47:51,120 --> 00:47:53,400
Speaker 1: ten is s n right because it's got some weird

943
00:47:53,560 --> 00:47:54,160
Speaker 1: Latin name.

944
00:47:54,480 --> 00:47:57,040
Speaker 2: Oh, how embarrassing. How embarrassing.

945
00:47:57,560 --> 00:47:59,960
Speaker 1: But you're right that there are relativistic effects all over

946
00:48:00,040 --> 00:48:03,000
Speaker 1: at the bottom of the periodic table, for example gold.

947
00:48:03,520 --> 00:48:07,879
Speaker 1: Why is gold beautiful and gold colored? Whereas silver, which

948
00:48:07,920 --> 00:48:10,560
Speaker 1: has the same electron structure and is one above and

949
00:48:10,560 --> 00:48:14,040
Speaker 1: in the same column, is basically colorless. It's you know, silver.

950
00:48:14,520 --> 00:48:18,200
Speaker 1: The answer is relativity. The color of an element depends

951
00:48:18,239 --> 00:48:21,480
Speaker 1: on the photons it will emit and absorb, which depend

952
00:48:21,520 --> 00:48:25,640
Speaker 1: on the spacing between the energy levels, and relativity changes

953
00:48:25,719 --> 00:48:29,440
Speaker 1: those energy levels in gold much more than they do

954
00:48:29,600 --> 00:48:34,200
Speaker 1: in silver, which makes it gold colored. Without relativity, gold

955
00:48:34,239 --> 00:48:35,080
Speaker 1: would look like silver.

956
00:48:35,280 --> 00:48:38,000
Speaker 2: Oh my gosh, I know so much cool stuff happening

957
00:48:38,000 --> 00:48:38,680
Speaker 2: with relativity.

958
00:48:38,760 --> 00:48:41,520
Speaker 1: People always say relativity is beautiful. Now you know why

959
00:48:41,719 --> 00:48:42,320
Speaker 1: it's gold.

960
00:48:42,520 --> 00:48:44,759
Speaker 2: People are always saying that, like it's common on T

961
00:48:44,880 --> 00:48:45,880
Speaker 2: shirts and stuff like that.

962
00:48:46,719 --> 00:48:49,239
Speaker 1: People are saying that you're being ironic, but I'm not.

963
00:48:49,560 --> 00:48:51,520
Speaker 1: Relativity really is beautiful.

964
00:48:51,719 --> 00:48:53,719
Speaker 2: I do think it's beautiful. I do, And this has

965
00:48:53,760 --> 00:48:57,799
Speaker 2: been super cool. So how recent is this incorporation of

966
00:48:57,920 --> 00:49:00,680
Speaker 2: special relativity into our understanding of what's happening in the

967
00:49:00,680 --> 00:49:03,600
Speaker 2: periodic table. Is this something I think I'm remembering you said,

968
00:49:03,600 --> 00:49:05,000
Speaker 2: we've kind of known about it for a while, but

969
00:49:05,040 --> 00:49:07,839
Speaker 2: haven't been able to calculate it until recently, Like, how

970
00:49:07,880 --> 00:49:10,200
Speaker 2: recently have we started incorporating this stuff in there?

971
00:49:10,400 --> 00:49:12,279
Speaker 1: So you know, we've known about quantum mechanics for about

972
00:49:12,320 --> 00:49:14,920
Speaker 1: one hundred years and relativity for about one hundred years.

973
00:49:15,160 --> 00:49:19,319
Speaker 1: They were merged together into relativistic quantum mechanics only a

974
00:49:19,320 --> 00:49:22,160
Speaker 1: few decades after the birth of both of those theories,

975
00:49:22,239 --> 00:49:24,560
Speaker 1: so that's been for a long time. But in order

976
00:49:24,600 --> 00:49:27,080
Speaker 1: to do this calculation requires a lot of computing, So

977
00:49:27,080 --> 00:49:29,399
Speaker 1: it's only about ten years ago the people were able

978
00:49:29,440 --> 00:49:32,680
Speaker 1: to do this calculation and predict the melting point of

979
00:49:32,719 --> 00:49:36,200
Speaker 1: mercury more accurately than eighty two c And so yeah,

980
00:49:36,239 --> 00:49:37,719
Speaker 1: this is a pretty recent calculation.

981
00:49:38,480 --> 00:49:39,800
Speaker 2: It's a cool time to be alive.

982
00:49:40,760 --> 00:49:42,759
Speaker 1: It is a cool time to be alive. But while

983
00:49:42,800 --> 00:49:46,200
Speaker 1: mercury is amazing and gorgeous and fascinating, please don't play

984
00:49:46,239 --> 00:49:48,760
Speaker 1: with it, don't drink it, don't throw it at your sister.

985
00:49:48,920 --> 00:49:51,000
Speaker 2: You probably don't want to put a vial of it

986
00:49:51,400 --> 00:49:52,080
Speaker 2: on your neck.

987
00:49:54,160 --> 00:49:55,720
Speaker 1: Though it turned out pretty well for you. Kelly.

988
00:49:56,000 --> 00:49:58,479
Speaker 2: That was probably one of the less dangerous things kids

989
00:49:58,520 --> 00:50:00,680
Speaker 2: like me were doing in the nineties. We were sort of

990
00:50:00,719 --> 00:50:04,359
Speaker 2: free ranging around our neighborhoods. All right, well, I'm going

991
00:50:04,400 --> 00:50:06,960
Speaker 2: to get my special. Relativity is awesome t shirt M

992
00:50:07,560 --> 00:50:11,560
Speaker 2: because you've convinced me and I look forward to talking

993
00:50:11,600 --> 00:50:12,359
Speaker 2: to you next week.

994
00:50:12,800 --> 00:50:14,560
Speaker 1: That was good, and so for those few folks out

995
00:50:14,560 --> 00:50:17,960
Speaker 1: there keeping track, relativity has now explained two totally different

996
00:50:18,040 --> 00:50:20,840
Speaker 1: kinds of mercury, both the orbit of the planet mercury

997
00:50:21,080 --> 00:50:24,759
Speaker 1: and the melting point of the element mercury. Relativity is

998
00:50:24,800 --> 00:50:25,360
Speaker 1: all over it.

999
00:50:26,080 --> 00:50:28,880
Speaker 2: Ah. You know, actually, when I read your intro, I

1000
00:50:28,880 --> 00:50:31,280
Speaker 2: thought to myself, I don't know the story about how

1001
00:50:31,400 --> 00:50:35,920
Speaker 2: relativity predicted Mercury's orbit. Should that be another episode? Is

1002
00:50:35,920 --> 00:50:37,759
Speaker 2: there a thirty second version? Or should we do a

1003
00:50:37,760 --> 00:50:38,480
Speaker 2: future episode?

1004
00:50:38,680 --> 00:50:40,040
Speaker 1: Future episode? Let's do it.

1005
00:50:40,239 --> 00:50:43,400
Speaker 2: Future episode locked in? All right, Thanks for listening. If

1006
00:50:43,440 --> 00:50:44,799
Speaker 2: you want to get in touch, please send us an

1007
00:50:44,840 --> 00:50:47,880
Speaker 2: email at questions at Daniel and Kelly dot org. We

1008
00:50:47,960 --> 00:50:48,880
Speaker 2: can't wait to hear from you.

1009
00:50:49,200 --> 00:50:51,880
Speaker 1: Thanks for staying with us for this Chemistry episode.

1010
00:50:59,400 --> 00:51:03,239
Speaker 2: Daniel and Ellie's Extraordinary Universe is produced by iHeartRadio. We

1011
00:51:03,280 --> 00:51:04,480
Speaker 2: would love to hear from you.

1012
00:51:04,719 --> 00:51:07,640
Speaker 1: We really would. We want to know what questions you

1013
00:51:07,840 --> 00:51:10,480
Speaker 1: have about this extraordinary universe.

1014
00:51:10,719 --> 00:51:13,680
Speaker 2: Want to know your thoughts on recent shows, suggestions for

1015
00:51:13,760 --> 00:51:16,799
Speaker 2: future shows. If you contact us, we will get back

1016
00:51:16,840 --> 00:51:17,040
Speaker 2: to you.

1017
00:51:17,239 --> 00:51:20,759
Speaker 1: We really mean it. We answer every message. Email us

1018
00:51:20,800 --> 00:51:23,640
Speaker 1: at Questions at Danielankelly dot org.

1019
00:51:23,840 --> 00:51:25,960
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1020
00:51:26,080 --> 00:51:30,000
Speaker 2: on x, Instagram, Blue Sky and on all of those platforms.

1021
00:51:30,040 --> 00:51:32,960
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1022
00:51:33,120 --> 00:51:34,640
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