The Magic of Chemistry with Kate the Chemist
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This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. We've got a Cosmic Queries edition coming, all about chemistry. More on that in just a moment. Chuck. Hey. How you doing, man? I'm doing well, man. How you doing? Okay. Who's that sitting next to you? I got to tell you, only the most awesome chemist ever. Ever? Ever. Ever.

If you have anything called social media, then you have seen her conducting demonstrations of chemical reactions and explaining to you the wonderful world of chemistry. Chemistry. Kate the Chemist. Hi. Welcome to Star Talk. Thank you. And I have to, I need training on how to pronounce your last name.

- Beiberdorf? - Beiberdorf, perfect guess. Beiberdorf. - Beiberdorf. - So like Justin Bieber and then Dorf, that's what I always say. - No, that's wrong. - The alter ego of his fan club. - That sounds like a fan club. - I'm a Bieberdorf. - Bieberdorf. - I'm a Bieberdorf. Are you a Bieberdorf? I'm a Bieber.

- Oh, I like it. - Yeah, Bieber. - My students call themselves the Bieber dorks, so. - Oh, Bieber dorks, good. - Yeah, so I'll take that too. - That's good. - I like it. - That's cool. - That's affectionate. - That's affectionate. - I'm a Bieber dork. - So you're not just Kate the chemist in your social media. You are associate professor of instruction

and science entertainer. That's a thing. I'm glad that's a thing. Why can't that be a thing? That should be a thing. You know? And associate professor of chemistry, University of Texas, Austin. Yes, hook them horns. Oh, hook them horns. There it is. Okay. So you built this huge following on social media.

Blowing shit up. Is this what you do? That's what I do. Yes. That is so cool. So how does that work on Twitter or in the medium where you don't have a video? It's difficult, for sure. I mean, you can share a video on Twitter still. Yeah, but on Twitter, I try to be more academic, right? I highlight articles that I like or science. Twitter X, excuse me. Yes, apologies. Yes, thank you. But, you know, highlight good research or...

hot science in the moment. So it's easy to do that. But I will... Directing people. Correct. Yes. Yes, exactly. Or highlighting scientists that I like and saying, hey, you should follow this person or this person. But you are right. I mean, Instagram and TikTok are my big ones because it's very easy to get somebody to like you breathe fire. I mean, that's just fun and visually appealing. Yes, yes, yes. And so are these people who would not have otherwise been chemistry fans, do you think? And they're attracted to your clever...

of bringing it down to earth? Well, that's a compliment. So I will take that. But probably, yeah. I mean, honestly, most people hated their chemistry class. I hear that all the time. Right? Both of you? Yeah. And that's terrible.

terrible for me because it's my favorite thing. It's my absolute favorite thing. And so if I can... By the way, anyone in your role who's also trying to do that with math has the same story. People hated their math class. They don't have fire. I at least have fire. I have liquid nitrogen. I have tools in my tool belt that I can use to get kids excited about it. They got nothing. A calculator. It's not as exciting. Take a right five, ten digits. All right. So you have thought about

what would excite them visually and intellectually? Well, I was raised by psychologists. All of us agree on William James's theory of emotional memory. And so it's about if you have an emotional response to something, you're more likely to form a memory. So in the classroom, I can use fire. Like if I light my hand on fire, now all of a sudden the students are interested. And the research shows I have about 60 seconds to then teach them why that works. We're looking at her hand right now. The research shows that.

Yes. Rather than your life experience. Yes, also true, yes. That will also count as data, for sure. For sure, oh, for sure. So you're burning it like an alcohol or something? No, so you dunk your hand in water first, and so you cover it. Water has a really high specific heat capacity, and so it takes a lot of energy to raise the temperature of the water. So that's the insulating layer. Exactly, yes, exactly. So it acts like a lab coat. Then you grab bubbles that have been pumped full of methane. Methane is very flammable. You hold onto it, you can light the bubbles on fire, and your hand doesn't burn out.

as long as you keep your fingers open. If you close your fingers or you're wearing rings, now you have a problem. But it's totally fine. But now the students are interested. - But just to be clear, methane, such as the gas that comes out of- - Cows.

Is that what you were going to say? Okay, cow. Let's leave it at cow. Let's leave it at cow. We'll leave it at cow. It's a flammable gas. Right. So what you've done, at the risk of stating the obvious, is you've taken psychological research to turn yourself into a better chemistry teacher. Yes, 100%. 100%.

100%. Yeah, I mean, the point, at the end of the day, my goal is for students to become good scientists. Only 5% of those students become chemistry majors. So I really want them to be educated voters. I want them to be able to- In your class. In my class, yeah, my class. And so I want them to be educated voters. I want them to have quantitative reasoning skills, quantitative thinking skills. And so for me, it's all about building those skills through the lens of chemistry to try to make my students a smart scientist

like the best citizens we possibly can have. And how about your following? They just want to see stuff blow up. Blow up. More, yes. Or they can become like chemical engineers. Yes, that's for sure. You must know because they'll write to you. Yes, they do. So what do you know? They like the explosions. They like the really quick, fast things. They do not want me to drone on about the structure of an atom. But...

You never know when that will spark the curiosity that leads them to want to know what's behind that explosion. Yeah, yeah, there it is. My son started off with just chemistry and liked it so much that he's going to school now for biochem. Amazing. Yeah, he's going to be a biochemist. That's what he tells me he wants to be. You didn't tell me that. And I told him, don't be a biochemist. Own a biochem company. Yeah.

It's not a bad idea. Let's get some basic chemistry on the table, okay? I can't claim to even know the answer to this myself. What is a chemical reaction? Ooh, okay. So, chemistry in general is the study of energy and matter and how they interact with each other. And

And so a chemical reaction is when you have starting material, you do something to it, and you get a brand new product. So like if you're baking a cake, your reactants would be eggs, flour, sugar, chocolate chips, something like that. And then you add heat, right? You put chocolate chips in cake? I don't know. I'm just making something up. That's a waste. Well, maybe you

- You can melt it, so it's a chocolate cake. - Okay, good. - Something like that, there we go, okay. - A molten chocolate cake, okay. - That's good, that's good. - Okay, yum, okay, so then we have to heat it up, right? So you're gonna put it in the oven. - So it's an energy source. - An energy source. - Going into the cake. - Exactly, and then you're going to take it out and you have a brand new product. So a chemical reaction is you have starting materials, which we call reactants, and then you have a product at the end, which is the goal. That's what you're trying to produce, what you're trying to make, or what you're trying to study. - Okay, so now, there are many things you can do that with,

But then if you just wait long enough, this thing that you made turns into something else. Like iron turning into rust. Yes. So other things can happen even after you're done doing what you're doing. So they would happen without your intervention. Correct. So that goes back to being a spontaneous reaction. And so I'm going to jump into some thermodynamics. Pull me back if I go too far here. Plus, I'm hearing these terms.

It's easy to see now why people use the chemistry term to refer to human relationships. - Right. - We have spontaneous reaction. - Right. - Chemicals is in our chemistry. - Yes. - These are your words, not my words. - They are my words. - Astro, we don't have that. You got all the words for relationships.

- Okay, fair, very fair. So for a spontaneous reaction, this is a chemical reaction that will happen on its own in isolation. And so usually that's something that's exothermic, so it's gonna give off heat as it goes from the reactants to the products, and it's usually something that has an increase in entropy.

And so we know the second law of thermodynamics is to increase the entropy of the universe. And so if we have something that's exothermic, meaning it gives off heat, and then it has an increase in entropy, meaning the energy is spread out more so, that's a favorable reaction that would be spontaneous. That's just the universe just being the universe. Exactly. Without your intervention. Without my intervention. So that's a reaction that will happen on its own. So they don't even need me to do this. Okay, so does the formation of diamonds...

count as happening on its own. If that needs pressure and temperature and time. That's what I was going to say. What are your conditions? So I would say yes over time. I just can't put a lump of carbon on my table and wait for it to become a diamond. Not for us. We will never see that. No.

Even though I did get a lump of carbon every year for Christmas, but that's okay. I mean, we're not going to get into that right now. Sorry. However, I mean, is it really happening on its own or is the earth actually providing the conditions necessary to make that reaction happen? Great point. Absolutely great point. So on earth, we refer to something as SATP or STDs.

So standard temperature and pressure. If we're talking about thermodynamics, that would mean we're at 25 degrees Celsius, so 298 Kelvin, and then one atmosphere. And so those are the conditions where it would happen on its own naturally. - 25 degrees Celsius. - Celsius.

- A little higher than room temperature? - Yeah, 25 is what we call room temperature. - Oh, I didn't know that. - Yeah, 25, in chemistry at least, that's how we define that. And so that's probably like, I don't know, 73, 75, something like that? - Yeah, it's a little above 72. - Oh, 72, okay. - It's a little above 72. - 73, that's what I said, okay, cool. - Yeah, yeah, yeah. - Okay, and then at one atmosphere. - At one atmosphere. - Of pressure. - Of pressure, right. And so that's how our chemical reactions occur here on Earth because those are what our standard conditions are. - So I heard something. Was it, is it beryllium?

One of these elements on the periodic table in American charts is listed as a liquid.

but in the UK, it's listed as a solid. That's gallium. Gallium. Gallium. I was like, beryllium. It's okay. Sorry. Her voice was stupid. So we talk about gallium. Gallium. Gallium. So in the UK, it's listed as a solid.

Because the room temperature in the UK is colder than here. Wow. And it changes state at that point. So the conditions are everything. What you think something is... Is only what it is under those conditions. Under those conditions. Exactly. That's it. Yes. Very cool. So one last thing about these...

exothermic reactions. There's also endothermic, if I remember correctly. So that's exactly what's going on. If you have a sore muscle, you get this pack and you sort of smash it and it becomes warm. There's another pack you can buy, you smash it and it becomes cold. So people like you have something to do with that. Oh, thank you. Yes, I'll take credit for that. Absolutely. Yeah, your people. My people. Your people. So you have special chemicals in there, which when combined, forcibly combined,

will either absorb energy or emit energy or release energy.

And so you have to know what those are in advance, obviously. Oh, yeah, absolutely. And so usually how those things work is there's one pouch that's filled with something, and then there's another pouch in the inside. And so you're breaking the two pouches and allowing for the two things to mix. The membrane between them. Right, exactly. It's a really thin membrane, and just with a little bit of force, we can break it. What's neat for endothermic reactions is it's usually a salt, a salt that will dissolve in water. That's going to drop the temperature down. It's freezing point depression. And so that's what's going to be very, very cold, and we'll use it if you have an injury.

Right. Okay. And that's what they do when you make ice cream. That's why they use salt. Yes. Oh, yeah. That's right. Well, I think there's a different reason. Really? Yeah. Why? If you make it by your hands, though, you add a little bit of salt for it so that you can go back and forth. Yeah. Make ice cream in your hands? You put it in a Ziploc bag and then you put milk and sugar and vanilla. Oh, you can put it in a towel and you put that inside of another bag of ice and salt and then take the towel and just...

Whip it around. Here's what I'm saying. I'm an ice cream guy. Okay. From way back. All right. I should weigh 100 pounds more, but I exercise just to wear off the ice cream. Just enough to wear off. Just so I can eat ice cream. Got your bucket. It's filled with ice. Right. If you try to make ice cream that way, the cold of the ice is only pulling the heat out of the ice cream at the points where the solids are touching the rotating cylinder. Everywhere else is air. All right. You put salt on the ice.

the ice melts at that temperature. Right. So now the medium is liquid. Liquid. And the liquid is now touching every single part of the cylinder. And it is way better. But it is the same temperature. At the same temperature as the ice. Correct. That makes sense. It is way better at sucking the heat out than just solids that it's turning into.

All right. I'll accept that. Cogent argument you have made. That's all I'm saying. Which I should have known because at first I was just like, all right, I finally got this guy. No. I'm like, I know for a fact that it's to lower the temperature, but that makes perfect sense. Yeah, yeah. So I would claim that salt in water does not lower the temperature. That's what I'm claiming. Salt in water will always have freezing point depression. That is a thing. We can measure that. I get that. Yeah. But if water is at a given temperature and salt is just the salt,

I'm going to assert that you put the salt in the water, nothing happens to the temperature. That's what I'm going to claim. False. Freezing point depression. It will go down. Delta T is equal to negative IKF times the molality. Mic drop! If you put salt in water, it goes down by negative 1.86 degrees Celsius. It's molality, so it would be moles of solute divided by kilograms of solvent. It doesn't matter what kind of salt. Definitely.

- Definitely. Yeah, it has to do with the Van't Hoff factor. - Oh, okay. - Yeah. - But at home you just have table salt. - Correct. And so it has a Van't Hoff factor of two. - So will this work for table salt? - Absolutely. Yes. Because when you put sodium chloride in water, it's going to break apart into the ions. - Okay, I'm doing the experiment tonight. - Do it. You will feel it. You will feel it in your hand. - I'm doing the experiment.

Cool, man. I love it. The experiment gauntlet has been thrown down. I promise you. Okay, so how many degrees? I challenge you, sir. Ions at dawn. Two Celsius max. Two Celsius. Max. Of what volume of salt? I would make a super saturated solution. Oh. Yeah. So take a bunch of water, just dump salt in until you can see it at the bottom. Yeah. Stir, stir, stir, stir, stir. And you'll feel it. You will physically feel the temperature go down. So...

I got a super saturated, a lot of salt. Just, yeah, but don't do a lot of water. Just do a cup of water and just, like, you'll feel it.

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So from our family to yours, make it treetop. Farmer grown, farmer owned. Hello, I'm Alexander Harvey and I support StarTalk on Patreon. This is StarTalk with Dr. Neil deGrasse Tyson.

Well, you have a huge fan base and they heard you were coming on the show and we solicited inquiries from them. Exciting. And what do you got here? I haven't seen them. Have you seen them? No. Nope. We don't let them. Oh, yeah. Okay.

It's a loving group. Yeah. They only ask things that they're really a great audience. Yeah. They're very curious. Okay. And they pay for the privilege to ask a question. Yes. They are Patreon members. No, just for a month. It's $5 a month if you're interested out there and you want to join Patreon. Which is the cheapest membership of anything you would ever have. All right. Here we go. This is Samuel Barnett. He says, Greetings from London, England.

Given the properties of molecules don't seem to match the properties of the elements they're made of. Example, water extinguishing fire despite being made of highly flammable oxygen plus hydrogen. Right. Which we learn that's the big tanks on the rockets that take the space shuttle to space. Yeah, the orange tank right there. The orange tank. There it is. So he says, is there a way to tell how a new molecule will behave ahead of time? Or is it just...

a case of suck it and see, or I'll... I'd love that. I'll say, I'll clean it up for him. Trial and error. Can you predict two new elements when they come together and they make something new? Can you predict its properties? Yeah. We will try to. So the periodic table is organized based on size.

- Size, but it's also based on chemical properties. - Size meaning size of the nucleus. - Size of the whole atom. - The whole atom. - The whole atom, yeah. So including the electrons. And so when you look at a periodic table, if you go down a column, you would expect for every species in that column to behave similarly. So for example, if you go all the way to the far right on the periodic table, those are your inert gases, your noble gases. All of them have full octet shells, meaning they're not looking for an external valence electron, they're full.

They're happy in and of themselves. They're satisfied. There's got to be some psychological...

Yes, exactly. You're content. I really like it here. I gotta tell you, this electron shell just suits me perfectly. I know, I don't need anybody else to help. I don't know what it is, you know? I'm looking down at my nucleus. I'm just as happy as I can be. There it is. Perfect. The right-hand column personified by Chuck. Yes. Okay. But you would expect everything. So like argon, neon, krypton, all those gases to behave in a similar way. And so let's say you look at group

five. You've got nitrogen at the top, phosphorus is right underneath it. So you would expect for nitrogen and phosphorus to behave similarly. And that makes sense. In a reaction, in a chemical reaction. In a reaction, if it's bonded to the same partners. So I would compare NH3 with pH3. And I would expect them to behave similarly, not the exact same way. NH3, so that would be

Ammonia. Ammonia versus pH 3 phosphine. And so we could compare the two of those and expect them to behave similarly. They each have a lone pair. They've got an electron pair available. Interesting. That's a fair answer. I like that. Oh, totally. Yeah. You can predict it, but then you test it. Right. You predict it and then you blow something up. Yeah, but I bet people before you understood...

the periodic table, there must have been a lot of trial and error. Of course. There still is. There's still trial and error. You have a guess. You want to use your money the best you possibly can. You only have limited funding. So you want to put your eggs in the best basket. Yeah. So how about now there's something in AI,

I believe it's called offline reinforcement learning. So what that does is the AI observes a bunch of things similar, and then it makes predictions based on what it's observed. Do you guys use anything like that to figure out? That's the definition of science. That's what we do. Duh. Right? I mean, right? We watch something. We try to detect patterns. That's all we learn in grad school. We don't use AI. We use NI, natural intelligence. Oh, okay. Right on. Yeah.

I'm going to say that's a little more rare. All right, next question. We don't find that very often. All right, this is Mike Muhammad Kaki. He says, greetings, Dr. Tyson, Dr. Biberdorf, and Lord Nice. Mike Kaki here from Berlin, Germany. Can you explain the role of activation energy in a chemical reaction and how it influences the rate of reaction? I love that. That's a beautiful question. What is activation energy?

- So activation energy is the minimum energy required for a chemical reaction to occur. - So it's sitting there otherwise happy. - Yeah. - Until you put energy in it, then it runs away? - Yeah, sometimes yes, sometimes no. It kind of depends on the conditions and what else is going on in the environment. But in general, if you're going to rearrange atoms, likely you're going to need to break bonds and then make bonds. And so activation energy is that minimum energy required to actually rearrange those atoms.

in whatever way is your intent. Right, exactly. And so there's, it's based on the collision. And so the orientation of the molecules matters. If you need them to head on and then they do like side by side, you might not have the collision. Wait a minute, you know how the molecules are oriented? Well, we know that what orientation, what collisions are favorable. And so we know if these two atoms need to interact and form a bond, if you have the molecules slap each other from the other side. How would you know?

- So do molecules have like docking ports basically? - I'm okay with that. - Yeah, but what I'm saying, yes, but how do you configure them to know which docking ports are pointing which way? Aren't they little than you can see? - Well, sure, but you know that if you have one side of the molecule, like let's say I'm a molecule and I know that my right hand needs to form a bond with your right hand.

if our left hands collide, we're not going to form a bond because those aren't favorable interactions. But how do you control that? We can't. Oh, okay. No. That's what spooked me. Oh, no. She's up there with tweezers, you know, putting one molecule That's the dream. I would love that. To another. All right. No, no, no. We can't because it's usually in solution or in gas phase. So the collisions are not. Yeah, we can't control that. Okay. No, but what happens

to happen is they have to collide with enough velocity, so kinetic energy, to overcome the potential energy push away. So the proton- That would count as an activation energy, the speed that they collide. Correct. Part of it. It's part of it. All of it. And so you have to have the energy coming in that is stronger than the proton-proton repulsions that are happening between the atoms. And it has to be at the right collision. All of that is kind of looped up into activation energy. And can you know that in advance? Like from...

or you measure that? 100%. Yeah. So you would use an Arrhenius law. So it's the natural log of rate one over rate two is equal to your activation energy divided by R times one over T1 minus one over T2. Arrhenius. Wow, you are good at this. I had to find it. Arrhenius. This is like way back. Way back. Yeah. Arrhenius. Yeah. When was Arrhenius? Ooh, I don't know. I couldn't give you a year. Long enough ago that nobody is named Arrhenius. Arrhenius.

That's how long ago it was. You have never met an Arrhenius in your life. An Arrhenius doesn't even have a middle or last name. It's like Cher. I'm Arrhenius. I love that. Yeah. You know what I'm trying to figure out, though, that some reactions are just so favorable or so common. Can you take what you said and I'm lighting a piece of paper on fire?

which is a reaction that everybody knows. What would be happening there from what you just explained? I would say the activation energy was the match. Mm-hmm.

I'm spitballing here. Part of it. But I'm thinking, I'm just saying. So if you have a fire, that's a combustion reaction. So you have a source of fuel, you treat it with oxygen, and you produce carbon dioxide and water. And so what you're doing is breaking all of the bonds in the fuel and the oxygen, and you're rearranging it to form carbon dioxide, CO2, and then H2O. And so it's all about literally pulling these species apart, pulling the atoms apart, and then allowing them to rearrange and form a new bond. And is it,

Based on what we said moments ago, is it fair to say that whatever is the configuration of the molecules in the paper, the configuration afterwards has lower energy?

Because that all that energy will release the energy right right is that a fire did I say that right if it's favorable Yes, if it's favorable you're going from higher energy to lower energy and but if we had to force that if we were in like Extreme conditions to make this happen then not necessarily you can force things to go higher energy, but usually That was cool man, thanks a lot. Can I do one clarification? Okay, so activation energy is about kinetics kinetics is the study of time thermodynamics is the study

study of energy. And so when we're talking about exo and endothermic, that's talking about the energy transitions. You're going from high energy to low energy, exo, low energy to high energy, endo. That's thermodynamics. And so that's, will it happen? Is it possible for this reaction to occur? Kinetics is how long. And so activation energy is really a measurement of how long something's going to take. So you need enough energy and it can guide us to figure out rate constants.

And so often people combine these two things, but it's will it happen as thermo. - At all. - At all. And then how long? And so from a standpoint of like going into the lab, I care about kinetics. I want to know how long my reaction's gonna take. 'Cause can I go home? Do I have to stay here all night? Like, so kinetics actually matters. So that's why people care about activation energy. - So you want the experiment to be done before you go to sleep. - Yes. Or- - Or before you die. - Right, or you can set it up and then go home and work it up in the morning. That's best case scenario. - Okay. All right, this is Lawrence Harris. And Lawrence says,

Good day, gentlemen and gentle lady. What is happening when you raise sugars to the candy temperature? It starts as a liquid, becomes a soft candy. But if you keep raising the temperature, it will eventually become candy.

- Hard. - What's up with that? - What is going on there? And by the way, worst candy ever. - And also, there it is, a liquid, and you think, oh, let me just taste that. It's like, oh! - Look at that. - That's way hotter than boiling water. - Look at that, I burned not only my finger, I don't have a finger, I have no tongue, I hate candy now. This is just a disaster. - I hate chemistry. - This is terrible.

So we talked earlier about dissolving salt in water. Yes. And it's a very similar thing. So you're going to dissolve sugar in water. They're going to form intermolecular forces. And so that's going to dissolve the sugar crystals with the water molecules. Will that also drop the temperature? In the beginning, yes. But it's not going to be as much because it has a van't Hoff factor of one. It doesn't break apart. That's somebody else. Yes, that's somebody else. Some other chemist of the past. And so for the ionic species, when you put them in water, they break apart. I want a Biebdorf factor. Nice, nice. I don't have one.

one. I should have one. You can't hang unless you have a factor. I know. All right. Well, next time I'll have one by the time we come back. But for sugar, you're going to dissolve. In theory, it would decrease your freezing point, but it's not going to be much because it's a covalent species. In the same breath, when you put sugar in water, it's going to increase your boiling point. And so that's why you can get that temperature a little bit hotter because the sugar is there to kind of mess with that.

So what's interesting about sugar is that when you heat it up, it's gonna dissolve. You're going to increase the solubility. And so that's- - That's true for anything. - For anything. Yeah, well, it's true for salts and solid solutes. But if you use a gaseous solute, you increase the temperature, it decreases. Yeah, it's the other way. - So if you boiled soda,

Then the gas just comes out. It doesn't stay dissolved in. Boom. Got it. It's the opposite. It's the opposite. Exactly. So when you add sugar in, you're going to heat it up and then it's going to dissolve. And so that's why you heat it. But it's the cooling process that really dictates whether or not you're going to have like a smooth candy or the hard candy, like rock candy. So if you don't touch it at all, you're going to allow for your system to kind of minimize the entropy, lock into these beautiful cages. Give it a chance to do it all by itself. Exactly.

Yes. Let it settle. And then you'll get these gorgeous rocks. And you probably have to put like a stick in there. But you'll get those rock candies that are typical of rock candy. But if you mess with it while it's cooling down, if you stir it, if you kind of shake it up a little bit, you can't form those gorgeous crystals. And so you're not going to get rock candy. You're going to get something closer to like fudge. And so it's a lot smoother. And so it's really, in my opinion, all the cooling process. And like how are you allowing those crystals to form? So it's not how you heat it. It's how you cool it. That's my understanding. No, that makes sense. My mom used to make candied rock.

sweet potatoes. Oh. And the way you start the candy process is, and they call it candy, it wasn't actual candy, it's a sweet potato with a sugar coating. But the way you start it is you just take regular table sugar, you put it in a pan, and under a

a low but intense enough to melt heat, you bring the sugar slowly up to a temperature where... Just pure sugar. Just pure sugar. No water, anything. No water, nothing. But you can't do it too fast because you'll just burn the sugar. Burn the sugar. But what happens is the sugar very slowly, as you watch it, you can see it from the bottom, as wherever the contact with the pan is, it just kind of splays out and becomes brown and caramel-like, and it slowly becomes...

this kind of gooey, like, caramel-like sugar. And then, depending on how you cool it or you do something to it, you stir it, whatever, but then it becomes like a syrupy fudge. And then when it cools, it just becomes like a little, like...

like caramel coating over top of the sweet potatoes. Your kitchen was a chemistry lab. Oh, definitely. Let me tell you something. It was one of my favorite things to watch. So kitchens are the thing. Yes, every kitchen is a chemistry lab. Thank you for making my point. Yes. Yes.

Because it's just, I need some of this and some of that. Yes, you're cooking. And so it lined up for you in all the cabinets. Yeah. You know, I didn't think of it until now, but that's absolutely the truth. Especially baking. Baking for sure is chemistry. Cooking is also, there's a time component. You can have fun with it. Baking is precise. You need to be exact. Yeah. But if you take...

from an egg, which is otherwise transparent. Then you heat it. Not many things will you heat do they then become solid. But the colorless part of the egg becomes solid. Yeah. That's kind of weird. Well, it's all about those proteins, right? I think they're opening up and then they can form bonds between each other. Right. So I've seen this done and I thought it was magic where if you take sweetened condensed milk, okay, and you boil the can closed for like an hour, right?

Then pressure builds up in the can. And then you come back and then you open it. And it's like caramel pours out. Wow. Okay. You haven't done that? I have not done that. Oh my gosh! I'll try that. I thought it was the experiment that gave the chemist...

Hasn't done yet. No. So sweetened condensed milk. Okay. Okay. So it must have a really high sugar content. Yeah, because sweetened and it's condensed. Yeah, and it's condensed. Yeah, use it for things like key lime pies. All kinds of baking. Like this baking. Yeah, oh yeah. Where you need the milk, but you don't need as much milk. Sure. So you'd have reduced milk. It just must have a lot of sugar though if it's able to turn it into essentially the liquid candy. Yeah, but with the milk. With the milk. It's not just. So it's a fat.

piece, so that must give it the creaminess or something. Oh my gosh. When I saw that done and they opened the candy pour, I was like, no, wait a minute now. Come on now. I thought they were... I don't know. I think that's how they make dulce de leche. That's what I'm saying? Yeah, I'm pretty sure that's how they make it. It was very dulce de leche. Yeah, yeah. Yeah, it's pretty cool. That sounds good.

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Caleb surely knows. Yes, exactly. Go ahead. Caleb says, good day. This is Caleb Lillard from Dallas, Texas. Considering the increasing attention being given to the awareness of PFAS chemicals and how prevalent they are in everyone's lives, I honestly was just wondering if what is being spread through typical means of communication is more hyperbole or if it should be associated with the level of gravity with which it has been paired.

All right. So anyway, this question goes on and on. But really what he's saying is this. Are PFAS as dangerous as we think they are? Are these these things that never go away in the environment? Yes, exactly. I heard about it, but I don't know anything about it. They're called forever chemicals. Exactly. And what is the acronym for? So it's PERFORMANCE.

per- and polyfluoroalkyl substances. Okay, let's keep it at PFAS. PFAS, yeah. Duly abbreviated. Yes. But the big piece is they have a carbon chain as the backbone, and then they're connected to fluorine. But wait a minute, doesn't everything have a carbon chain? A lot of things, not everything. Aren't we just carbon chains? Yes, we are just carbon chains too. But for PFAS,

- So, very fast, they've got this carbon backbone and they're connected to fluorine and they're really strong carbon-fluorine bonds, really strong. And so that's what make them forever chemicals. - Right, 'cause they can't be broken down. - Not easily. - Not easily. - Not easily. - Or it takes a long time to break them down. - Wait, so those chlorofluoro... - Carbon CFCs. - That's fluorocarbon, it's in there too.

chlorofluorocarbon. So that usually is a much smaller molecule. And so it's like, my memory is that there's carbon and then it's attached to a couple things. From the refrigerant. The ozone hole. Killing the ozone. Okay, sorry. I'm confusing the two. It's okay. Go ahead. But that's good to clarify the difference. So CFCs are much smaller, but they also are bad for the environment. They're gases. So PFAS here are much bigger molecules. And so if they get into our body because they're forever molecules and we can't break them down as easily, they stay.

They stay in our body. And so that's a problem. And this is a... Just to be clear, you have to quantify it for me. How big is a big molecule? Well, it ranges and that's the problem. So there's 15,000 different molecules that can be considered a PFAS. And so that's the problem with this. It's really a generic term. At the end, we're just PFAS chemicals. Yeah, I'm going to say that's not hyperbole. It's not hyperbole. That is scary as hell. Yes, and it's...

Particularly troubling for women. We know that causes fertility issues. We know that in young women, so teenagers or girls who have yet to go through puberty, it is causing a delay in puberty. So we're seeing that issue coming up. But why can't we just poop it out?

Well, I think it's because it sticks with inside of our body. It must be forming some kind of like intermolecular force with the inside of our body. And so it's strong enough because I wouldn't be surprised for, I'm speculating, but I wouldn't be surprised for fluorine to easily form some kind of intermolecular force with something in our body. They have three lone pairs on them. So it's really easy. Through the digestive tract. Yeah. Anywhere. Okay. So is it hyperbole? And where did, wait, back up. Where did these come from?

- They are generated, we make them a lot of times, yeah. I would say actually, I think all the times we make them. - On purpose? - Yeah. - For what?

Plastics, basically. Linings inside of bottles. So we're killing ourselves, basically. That wouldn't be the first time this has been a thing. We have a pattern. We have a pattern. We're sensing the pattern. So it's in the environment. It's in the environment. We ingest it and they never leave our bodies. Yeah, in theory, right? And I'm sure the smaller ones probably you can leave. But the bigger they are, the more likely it is for them to form a bond inside of our bodies. And so it's problematic.

Am I going to try to eat PFAS? No. Am I going to try to avoid it? Yes. So I don't think it's hyperbole. I think we really should avoid it. Okay. Wow. Good question. If it's plastics and linings, there's no FDA label for PFAS. So you have to just read articles that highlight it, right? So what's the biggest source of PFAS into our society?

Well, I don't want to point fingers, but a lot of times it has to do with chemical waste, right? And if we're not disposing it properly, then it can get into our water system. Why don't you want to point fingers? Well, I mean, I should point fingers. Because those companies are chemical companies. Yes.

I'm just saying. Because they'll point their finger back at you. And I want to get hired. I'd rather be on their side and then advocate for good science and maybe help them fix the problem. So I want to be a chemical advocate. Rather than play a blame game. Correct, yes. I want to help. Two different tactics. Correct. Yes.

All right. All right. Okay. Well, thank you for that. That's a good question. Yeah. So this is Alan Rayer. Alan says, hello, Dr. Kate. Privileged to follow you on Instagram. Oh, thank you. There you go. It's Alan from Lithuania here. What gives colors to the elements? Why does the color change in an element based on molecular bonds? Ooh.

- Ooh, I like that. - Okay, so couple different answers here. It depends on the context of the question and what we're specifically looking at. So if we're looking at metals, just generic metal in the neutral state, when we have an excitation, our electrons are gonna move. They're gonna go up in a level, think stairs.

So they're quantized energy levels. So the electron will literally drink a Red Bull and then run up a bunch of stairs. That process isn't normal. But when they fall down the stairs, just like if we as humans fall down the stairs, we're going to scream and release energy. Electrons do the same thing. So as they fall down these stair steps, these quantized energy levels, they release energy in the form of visible light. And so if you have a big gap, you're going to see a high energy light, blues and purples. Is that what he's asking? Or is it more simple, just different things have different colors?

But that's why, though. Rather than glowing, that's a glowing metal, right? It's an excited metal giving off light, right? Like tungsten. Okay, but what?

Yeah, yeah. Well, that's thermal, though. That's thermal, yeah. That's different, yeah. Okay, but what about a quantum dot? So a quantum dot is something where if it's really small, like two nanometers, we're going to have a color of blue being emitted. But if it's a little bit bigger, with six nanometers, not that much bigger, we'll see a color of red. Yeah, exactly. Oh, that's the wavelength of the light. That is giving off. That's really wild. Get out of here. Yeah, that's how I think about it, is how just like it's emitting light, and that's the color we see. So that's the context I usually use. So what about all the things that are colored?

Oh, well, they are not emitting something. Or just white, you know, like salt and sugar and flour. And, you know, there's so many things that just have no color. Well... The kitchen would be so much more interesting. No color that we, that our human eyes can see. We only see the visible spectrum. So we can see from 400 to 700 nanometers. Physiology. But if it's outside of that, we don't see it. Stupid human eyes. Your big, dumb human eyes can't see anything. Yeah.

The way she said it. Damn. It's true. She acted like she could see outside that spectrum and the rest of us can't. I can't. All right, keep going, Chuck. All right, this is Daniel Gilligan.

Daniel says, greetings, friends. Daniel here from Tasmania, Australia. Okay. What was that? That was my Tasmanian devil. Really? Is that even allowed anymore? He says, how come water isn't the most flammable thing in the world, especially salt?

Water. As separate elements, oxygen, hydrogen, and sodium are all very spicy when it comes to being flammable or dangerous. So let's start this off. What happens if I put a hunk of sodium in water? You're going to see hydrogen gas is going to be evolved, which is extraordinarily flammable. It's an exothermic reaction, so usually it will ignite and you'll see a flame. Boom.

That's the chemist way to say it. It's going to blow up. A lot of, a lot of. That's sodium and sodium isn't stored. Sodium chloride, salt. And then we know. But they're different. Those are different. Sodium that you throw into the water is a chunk of metal and that's an oxidation state of zero. But sodium chloride has an oxidation state of plus one. And so the answer, the short answer to the question is where are the electrons next to these atoms? And so it's how they're sharing them or they're transferring the electrons is going to dictate how they're going to be

- This is unbelievable stuff. - Wait, wait, so the molecule, you cannot infer the property of the molecule from the properties of the atoms that go into it. - You can if it has the same, if you're comparing like apples to apples. So if they are, if it's, if you're comparing CO2 versus SiO2. - That's one way. - That's one way you can compare. - However, I'm saying,

Like the questioner said, we know hydrogen is flammable. We know oxygen feeds flames. You put them together and it extinguishes flames. Yes. That's weird. It is weird, but they're so different though because hydrogen is H2. It's two hydrogens bond together. So they're sharing two electrons. You've got oxygen has a double bond between it. So they're sharing four electrons. That's a really strong bond. And then water has one oxygen and two hydrogens. Those hydrogens are not next to each other. The oxygen is in the middle. Yeah.

And oxygen is the second most electronegative atom that we know about, meaning it pulls the electrons from its species. So in hydrogen, the electrons are being evenly shared. In water, most of the electrons are completely up on the oxygen. And so it's all about where the electrons are and their reactivity. So oxygen steals electrons. Every time. Like no matter. It's just basically, it's a thief. Don't bring your girl around oxygen. That's the problem.

Perfect analogy. Don't bring your girl around oxygen. We know the deal. Oxygen is like Michael B. Jordan. Your woman is leaving with him tonight. Yes. That's exactly it. Okay. I'm going to use that in my classroom, by the way. Okay. Wow.

So, Kate. Yeah. I understand that you have a podcast. I do. An NPR podcast. Yes. Seeking a Scientist. We just dropped. Isn't that all the right investments in any three years? Going into it? Yes, exactly. So, we just dropped season two. And our first episode of season two was about being in space. It was the DART mission. We interviewed Nancy Chabot. Double asteroid redirect test. Yes, exactly.

Exactly. And so we go through the entire process from the beginning of the creation of the experiment all the way to now what's happening and what their future missions are planned. It's awesome. So these are scientists active in something that you might be interested in as a listener. Yes. And I would someday love to have a chemist on there, but yeah, it's

been completely other than chemistry. Like we're talking to someone who studies dogs and how you pick- It's not ask a chemist, it's just ask a scientist. We're seeking a scientist. Which could come from any field. Exactly. We've got this one woman who's doing research on puppies to figure out how you can determine what is the best service dog. Like that's her research is figuring out how to predict that.

So we interview her. And so that's coming up in a couple of weeks. The answer is it will not make a difference because in 10 years, all service dogs will be autonomous robots that actually just guide you. Oh, I love the golden retrievers. I want them to stick around. Yeah, guess what? Robots don't poop. Not yet. Not yet.

So it's filmed in your hometown, where you are, in Austin? Yeah, I film out of Austin, and we interview scientists from all across the planet. Wow. Okay, so virtually. Virtually, yeah. It's all virtually, but the host city is actually Kansas City, so I got to give a shout out to KCUR. Oh.

Okay. Yes, you are. Okay. As in the public station model. Correct. It's distributed. It's not one central creating point. And so they create it and then it's shared with other stations. All right. Okay. It's been a delight. Finally, we met over the internet, but not in person. Thanks for coming by. Thank you for having me. It's so wonderful. And sharing your media calendar with us here. Thank you. All right, Chuck. Always good to have you, man. Always a pleasure. All right. In conversation with a chemist, which doesn't happen to me often.

I'm just reminded how much of this world is enabled, empowered by chemists. What they have done for us has transformed our lives in every measurable way. Yet at the end, it doesn't say by the time you use your cold pack, when you're done and your knee is a little better from this endothermic reaction that a chemist put in here, it

Thank your nearby chemist. No, there isn't. There's no such instructions there. We just do it and take it all for granted. I should have a conversation with a chemist more often so that I take less of what happens around me for granted. If you don't get to have a conversation with a chemist, next time you make anything in your kitchen, just sit and reflect on the fact that none of that would happen without chemistry. And that's a cosmic perspective, not only on the universe, but on your everyday life.

For 60 years, families like ours have been growing apples for treetop applesauce and apple juice for families like yours. Ripe, juicy apples picked at the peak of perfection. And year after year, harvest after harvest, we've held to our core belief that the best quality apples make for the best tasting applesauce and apple juice.

So from our family to yours, make it treetop. Farmer grown, farmer owned.

Hey, Cam, mine's sending me over our new Wi-Fi password. Oh, sorry, Mitch, you can't be trusted. What? It's your phone. It's different than mine. Cam! And I thought I was the judgy one. No, it's just messages between different devices aren't encrypted. Okay. Since when do you know about encryption? I know what encryption is, and it's because I'm the last line of defense against any would-be Wi-Fi thieves. Cam, come on. Okay, fine. I'll send it somewhere more private. Thank you.

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