Grab an ice cube and put it on the counter. Then very lightly sprinkle a bit of table salt. Now put a piece of string on top of that salt, and observe. The salt will melt and it will look as if there is a puddle of water. But the -2C will make the ice freeze the string inside of it, and you can lift the ice cube with the string. Totally relevant to the whole ice-salt-temp discussion in today's show.
I think all of us wish we had a teacher like her my Chem teacher was some 65 y/o man who was just waiting to retire it was the most boring class i took.
Chuck is there for the typical viewer to make it less nerdy, dorky, whatever. Love having him on Star Talks. He often says what I'm thinking. Thanks, Chuck.
I was thinking something similar. He’s probably the smartest person in 99.9% of the places he is at but probably the dumbest (sorry Chuck) on these 3 ppl panels on Star Talk
14:14 I love this. When presented with a new/differing information from what was initially understood, you note it down, you go back, you study and do experiments. And you know what, you just know that after Neil is done with the experiment, he'll feel so happy that he learns something new, rather than feeling crushed because he got his understanding wrong all this time.
Ok, l will admit it, I am now addicted to Science and Technology. Learning is so much fun with these three brilliant people. Cheers from Michael. Australia.
I like that Dr Tyson admitted his uncertainty and said he'd do the experiment. He knows how to prove who is right and will wait until then. I expect an explainer later on how it works
She was referring to freezing point depression but describing enthalpy of mixing instead. Freezing point depression is not a decrease in temperature of the solution, it is the decrease in the freezing point of the mixture. Enthalpy of mixing is why solutions will change temperature when the components are mixed together.
"How is freezing point depression used in everyday life?" "It is used in making ice cream, where salt is added to ice to lower its freezing point and make the ice cream mixture colder. It's also used in antifreeze for cars, where a substance is added to water to lower its freezing point, preventing the car's engine from freezing in cold weather." Isn't this what was being discussed?
@@marcd1981No, I was referring to a part earlier in the interview when NDT asked her if simply mixing a solution will change its temperature, and she said, yeah that's freezing point depression. 14:00
Indeed, I believe she is a little confused. I don't think the amount the water will cool is the same as the amount of freezing point depression the water will attain from that formula. But I give her points for one realizing Neil was confidently telling her the water wouldn't cool and was wrong, and two points for at least coming up with a formula even if it is the wrong one lol!
The salt in ice cream making is used to melt the ice (lower its freezing point) and maintain the salt water at or below freezing while distributing that temp more efficiently over the container the cream mixture is in. Next time you want to chill your beer in your cooler, add some water after the ice and it will cool much quicker because of the contact being all around the can rather than just the places the ice touches the can. You could add salt, but that might be overkill for beer.
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Chuck's contributions to this episode was absolutely AMAZING. Every joke, every interjection, every question so on point so expansive to the conversation. The chemistry convo definitely a favorite. Plz plz plz more like this.
Chemical engineer here, I completely agree, you've got to blow some stuff up in the classroom, my freshman chemistry professor Dr Jim blew stuff up on a regular basis, lots of hydrogen balloons and sometimes mixed with oxygen whoooa, which shook the building, and he did all kinds of other cool demonstrations, it was the best, and you will have your students hooked for life!
Chuck a HUGE part bc of his comic relief and saying ish us "normies" would say even though we know Chuck is being the "I'll ask that question guy" He seems very intelligent and nowhere near as dumb as he jokes about. Neil and his chemistry are so enjoyable to listen to, I don't even have to watch the pod sometimes bc it's such good conversation all around.
I found this absolutely educating, and in a humorous way. You slayed this episode. Switching it up sometimes, is the reason I enjoy Star Talk. Kate is a fantastic guest, and I hope you have her back! (When she’s talking about elements, I have to slow the video down to 25%, and listen to it 4 times, just to begin to wrap my little toy brain about it.) She’s very gifted. 😎 Keep these great sessions coming!
This episode just reminded me of my chemistry classes and how damn happy I was to learn all of that!!! The happiness in the eyes of the guest talking about chemistry is just great and makes me nostalgic of my chem classes!!😢😅
I'm Riccardo, chemist and science communicator from Italy. I am part of the Italian Chemical Society as I put my expertise on the line to help researchers be better communicators. I really didn't like the answer about PFAS: chemistry world has problems such as chemophobia mainly because of the behaviour of chemical companies and saying "I don't want to point fingers because I want to be hired" makes the problem even bigger. Chemists and chemical companies are not the same thing, they not belong in the same environment and they don't use chemistry knowledge in the same way, so if companies create a problem, it's not chemistry fault: it's company's fault. Chemists wants to solve problems, not create them. We need to create a different perception of chemistry as a subject free from industrial interests and closer to basic research. Astronomy is a big example of what I'm saying: there are giant industrial interests around it, but it keeps a pure perception.
This is my introduction to Kate the Chemist and I just followed her everywhere! Love her passion for chemistry and could listen to her for days. Thanks to Startalk for the intro :)
About PFAS, they use them in firefighting foam, the foam floats on top of petroleum and deprives the fire of fuel, I was in the Navy and we use this to fight shipboard fires. Now, at 68 years old and having been retired over 30 years I was just diagnosed with tumors in both kidneys. The PFAS stays in the blood system, it has an extremely long half life, they suspect this is what caused my cancer.
Hey guys! Just thought I’d shoot an answer out there for the question at 16:05 because I do research in this field at my university. We currently use deep learning neural networks and machine learning algorithms using schrodingers equation to predict the stability and properties of newly developed molecules. We run massive simulations on a supercomputer on campus to generate and process data. From the data, we draw conclusions on aforementioned subjects.
One of the most prominent sources of PFAS contamination is fire retardants. Consequently PFAS contamination is known to be especially serious in proximity to sites where firefighter training has occurred because of repeated use and exposure.
Lots of talk about this now in the fire service... especially where our hood comes in contact with our skin. For years guys didn't wash their gear out of pride ("look at the fire activity I've been in")... I'm glad for the research to keep us safer now.
Something that some may not know is that because California had mandated fire retardant in furniture until 2013 many older couches are made with lots and lots of fire retardant in them. This leeches into your body as you sit or just touch it. It is supposedly easier to figure out today now that the law is gone and replaced with a new one but it is still a very really possibility that if you sit on a couch you could be getting the chemicals inside of your body. Watch out for those PFAS, they'll get you.
I watched it when it came out. Great movie. There's a Graham Norton episode with Mark Ruffalo to promote the movie, and the actual guy (on whom the movie was based) was also in the audience. That particular episode is worth watching, too.
Excellent, I'm sure that I have never enjoyed learning as much as the last 43 minutes. Kate is absolutely charming, I would love to be in her classroom.
My Argentinian mother in law have been making making Dulce de Leche through sweeten condensed milk cans. It's a staple for sweets in the Argentinian culture.
14:17 The temperature will go down but not due to the reason stated, "freezing point depression". It's in the name. It's the decrease in the freezing point of water, i.e. it's temperature of water will need to be lowered beyond 0 degree Celsius to freeze it. The reason dissolving NaCl in water lowers the temperature is because the NaCl molecules break down into ions in water and thus absorb energy from the water, i.e. it's an endothermic process
I was just researching this because I was also confused about the reasoning. Energy is absorbed (endothermic) when salt is dissolved in water which is why the temperature of the solution will drop, not because of freezing point depression. Unless maybe you could calculate how much the temperature of the solution would drop by using the freezing point depression formula? Then the freezing point depression reasoning would make more sense. But I'm not sure.
This is what I thought as well. I don't know how you would use the freezing point depression formula to calculate the energy used in that reaction or why you would do it that way. I think maybe what she meant was that if you add salt to ice there freezing point depression causes the ice to melt and the energy needed for melting makes the temperature go down. This works in the ice cream scenario but wouldn't happen with room temperature water though, so them describing an experiment with a cup of water after doesn't make sense.
I had to type about a 300-words explanation to this problem and then i posted the comment before deleting it after 5 minutes. It felt too cocky for me. Glad to see someone else did it. Good job!
Many non-stick cookwear is essentially made with PFAS, which is very insidious because you're cooking and eating these chemicals directly. But as she said there are many sources - many PFAS also get into groundwater from industrial manufacturing - 3M is one notable company that makes all kinds of PFAS materials.
Clothing in the laundry is probably the big one. Wrinkle-resistant stuff puts forever chemicals in the water, and also microplastics if it's a synthetic material.
DuPont tried to overthrow the government in '42 and succeeded in '80 through his support of the American Liberty League and a helluva lot of wicked corporate propaganda, including the creation of the modern megachurch.
Dryer lint i believe to be a large source of microplastics loaded in the majority of households it is simply vented outside it's full of microscopic polyesters and various microplastics
36:45 I'm imagining a pair of glasses that allow you to visualize different ranges of the spectrum, and how beyond amazed Neil will be when he first wears a pair.
we kind of do that already, we translate invisible parts of the spectrum in something that our brain can understand on a screen. the point is we don't need to see that kind of light, it's too much! our brain would be too busy and we would be constantly blinded by wi fi, our oven, our phones, the uv light from the sun, the cosmic rays, our own body temperature... not great. we can use a screen and technology just fine! we could use some kind of augmented reality glasses instead yeah! but it's basically like a screen. our eyes are already fantastic for what we need to do as a species!
Well, it's not like Neil works in a field that points telescopes that can see outside the visible light spectrum and map it to the visible light spectrum to create pretty pictures for the press, right?
Missing from this discussion about PFAS, its in our food because many pans at home and in restaurants use non stick pans that when heated above 400 degrees release PFAS into the food. In addition other products contain PFAS. For those of us who fight fire, our bunker gear is impregnated with PFAS. This is very bad as we enter structure fires which have internal temperatures often exceeding 400 degrees and our skin becomes more porous as we heat up, to absorb PFAS. I have scientifically linked thyroid disease and mast cell leukemia from PFAS. Thank you 3M and Dupont. She is on the wrong side. I have a feeling if it were her with cancer (incurable) or a loved one, she would be approaching this from a totally different position. Chemists have a responsibility to study new chemical creations BEFORE releasing them to the general public. When they do not conduct these studies, they should be held to account. Especially when people are dying for their irresponsible science.
I think Neil Tyson sir was asking about exactly orienting the atoms and colliding them.. that isn't possible but ya catalysts and enzymes do the work kinda but we arent pinpointing single atoms
There are different levels of control in reactions. I think the type of control Neal was talking about is the type that we're hoping nano machines would be able to provide, at the individual molecule.
I really enjoyed meeting Kate. I will look for here videos. My chemistry teacher in high school made me like chemistry. It is great to have a teacher the excites her students. This was a very exiting episode.
From my understanding, many PFAS are used in waterproofing, and these new sprays that can waterproof things are a problem when not wearing protective equipment
And Teflon non stick pans...and "stainfree" clothes/furniture/ carpet and water bottles/cans with white lining...the scotchguard spray we used to spray on suede items for "protection " and waterproofing 😢
Very interesting video, thank you. Be careful you don't anger the mathematicians because of the calculator comment. An easy way you can estimate when converting Celsius to Fahrenheit is double the Celsius number and add 30. Not an exact science, but it gets you close. Okay, 10 1/2 minutes into the video and I can still barely hear Neil. Chuck and Kate sound normal, I can hear them fine. If I turn up the volume to hear Neil, then the other two sound like they are shouting because the volume is too high. 24 1/2 minutes in and man, does Kate love what she does, or what? I wish my career had been doing what I loved as much as she does. At a little after 26 minutes, Kate mentions the word "species" again. She first mentioned "species" when she was talking about the periodic table earlier in the video, and said if you took one column, those "species" would have similar chemical reactions. I have not heard this term used to describe elements, and I had to look it up. Here is one definition I found: "Generally, a chemical species can be defined as an ensemble of chemically identical molecular entities that can explore the same set of molecular energy levels on a defined time scale. Chemists also use chemical species to mean a set of chemically identical atomic or molecular structural units in a solid array." At about 30:30 a question about PFAS was presented. Is anyone at this channel, or anyone watching this video, familiar with symptoms, or know people that have had any issues with these chemicals? Thank you again for the video, great stuff!
@@alswedgin9274 That would seem to be way off of the actual temp. When you add 30, you are within a couple of degrees, such as in this case. 25 x 2 = 50, Adding 30 gives you 80. The actual conversion comes to 77 or 78 degrees. If you only added 15, that would give you 65 degrees, which is 12 or 13 degrees off.
This Terrence Howard nonsense needs to stop! Howard has stated that he "went to school for chemical engineering and applied materials". Though he did not complete his engineering degree, Howard thinks of himself as an engineer and intends to return one day to complete the "three credits" of which he claims he is currently short. Howard's account of his educational history has not been confirmed; Pratt Institute, which he says he attended, closed its engineering degree program in 1993. On February 26, 2013, Howard also said on Jimmy Kimmel Live! that he had earned a PhD degree in chemical engineering from South Carolina State University (SCSU) that year. He however never attended that university and in fact SCSU does not confer doctorates in chemical engineering. Instead, Howard was awarded an honorary degree of "Doctorate of Humane Letters" (DHL) from SCSU after speaking at its commencement ceremony in 2012. Howard is the sole inventor listed on US Patent US20100271394A1 titled A "System and method for merging virtual reality and reality to provide an enhanced sensory experience," which has has been cited by Amazon, Microsoft, HP, Sony, Raytheon among 30 other Major Corporations, it was later abandoned by Howard. In 2010, Howard was inducted as an honorary member into Phi Beta Sigma fraternity.
This is the best Startalk I’ve seen, Kate is so knowledgeable and engaging I had no interest in chemistry before I saw this. Great video thank you all.
I also thought it said peas at first glance. I was hoping for discussion informing millions of the benefits of a low arginine diet to avoid shingles. If I remember correctly, peas have a high arginine concentration. The shingles virus is built with arginine, and yet elderly care and rehab facilities regularly supplement diets with arginine and truly do not understand when patients breakout in shingles. I did my research too late and learned the hard way. Perhaps there were one day be a discussion about the potential peas and shingles link. Your body can make arginine as needed from lysine or other amines so there's no need for a diet that supports a virus. As always a balanced diet is key. Arginine isn't necessarily a problem, it's too much arginine alone that's a problem,
It would have been amusing to see a subversive kind of video where Neil asks "so how dangerous are peas?" and she just says "not very", and that's about it
Do people who watch Joe Rogan bringing on grifters and pseudo intellectuals ever watch conversations like these and realize the difference between the science and evidence based interactions witnessed here versus the ego stroking interviews Rogan engages in? The funny thing is Rogan fans will claim they listen for the “honest” conversations.
Rogan does have honest conversations, it’s just from a completely separate perspective. Joe has the conversations from the perspective of someone like you and me. Someone who doesn’t really know anything about what the guest is talking about, but wants to learn more, without having to have spent years studying any of it, in order to gain that knowledge. What you get here, is a conversation between two people, who spent their lives studying within their specific subject fields. And both of their fields share some layers of overlap within themselves, so they have real grounds of mutual understanding. Something that people like you, me &, Joe Rogan, do not possess. Be humble.
I know the intro helps get people to watch the video, but I'm not a fan of it. I get why you did it, I just have to fast forward through it and am wondering if youd put a chapter there to make that easier?
I found it hilarious that Neil doesn't like the feeling of not being the smartest or corrected on his own podcast. Kate was an amazing guest and his equivalent as a chemistry educator. I will definitely follow her from now on. She's so good at explaining things and her passion comes through in her words and excitement.
Go to 13:55 for the moment when Neil tries to make a claim and is educated on the facts. He still wasn't convinced and like a true scientist states he will do the experiment tonight to prove to see if she was correct or not.
As someone that works in the environmental remediation field and has investigated PFAS sites, PFAS is in everything. It's the main chemical in Teflon (yes non-stick cookware), anything that is water repellant will have PFAS (rain gear, umbrellas, makeup) synthetic clothing, Sharpies, food (microwave popcorn...the inner bags are lined with it to stop the kernels' from sticking/burning to the bag, but you can get microwave popcorn that is chemical free...thank you Skinny Pop), it was in older fire extinguishers for JP-8 jet fuel that fire fighters used on flight lines. So she is correct, PFAS are no joke at all and need to be taken seriously. Netflix actually has a documentary on PFAS, it is a few years old, but definitely worth the watch.
It’s called Dulce de leche. Nestle sells it. Or you can do it on your own, can of sweet condensed milk. Boil in water ( cover sealed can) for a couple hours, let cool ( do not open till cool) and BANG! You have caramel. It’s delicious.
Now that I am retired (from engineering), my brain hungers scientific principles. These videos are awesome to keep my brain fresh and occupy my thoughts. Thanks Startalk, Neil and Chuck.
The whole boiling condensed milk to make caramel is a very old school thing. These days you see it done still in Central and South America. A lot of people would just make caramel the normal way, but when you don't have anything and times are tough or you're just feeling a bit nostalgic, or you simply don't have the time to fuss. Boiling a can of "sweetened", it has to sweetened, condensed milk works great for a lot of applications.
Regarding of why PFAS can stay long in the body I have heard that the Fluoride atom takes the space of another atom in an important molecule chain. For example a simplication using a CFC, the fluoride atoms take the position of H atoms, (simplified) CH4 becomes CF4. For important long molecule chains the body cant distinguish if a fluoride atom took the place of an hydrogen atom but the important function of the molecule is lost. Therefore the impact on our body is that DNA doesnts form, Cell division is irregular etc.
You are pretty well on point. Its an enormously damaging class of substances that we are manufacturing 1000s of tons each year and their concentration in the environment raises relentlessly. Those fluorine chains are not slow to break down. They will NEVER break down in the natural environment. They require extreme energies, like from a laser beam to be broken. That is why it is so difficult to even test for them. they don't react with much at normal temperatures.
This is great. I loved the “suck it and see” reference. This is a genuine UK expression and is in no way rude. So funny to see someone else’s reaction to this catalyst.
Watching astrophysicist Dr Neil deGrasse Tyson learn some science stuff that I remember from high school was a real ego trip for me haha. Kate is an awesome guest, this episode was great!
PFAS is on alot of cardboard food packaging... Also they have designed a high electrical use way to breakdown PFAS in water, but it needs to be added to all water treatment plants.
The thing about the PFAS is that they break down and slough off slower than we currently take them in. They are in water everywhere, and as such they end up in things that are made with water (most foods) and they were not even tested for until recently. They have been accumulating in the environment since the 1950s starting with Teflon and then all of the associated similar compounds (those 15000 she mentioned) are derived from that. Think of non stick cookware, just about anything deemed 'waterproof' is coated with them, 'Scotchguard' that can be sprayed on furniture and clothes and is also embedded in most indoor carpeting. Even dental floss and toilet paper. Just crazy. The good news is they can be filtered, but you need the right filtration either at home or at your city water supply. Bottled water **IF** it is filtered for PFAS would be safe too, but nothing cooked from tap water would be safe without filtration first. Once we take action to limit them we will slowly purge them from our bodies, but it takes by most estimates around 7 years to do that. Safe levels for most things are measured in PPM parts per million while PFAS must be tested to PPT parts per trillion. It is so dangerous that safe levels of PFAS are much much lower compared to most chemicals. Testing has been done all over the world and based on that it is estimated that 99% of all humans have detectable levels. What they have the potential to do to humans is seriously gross. High concentrations use to exist near the plants that made them and major birth defects were caused. Child cancers and neurological disorders were common. Adults exposed through drinking water have higher incidents of cancers occurring with long term even low dose exposure. It's seriously bad stuff and we should all be way more aware of this poison all around us and in us.
I think something that confuses most people is not talking about the difference between Oxygen the atom and Oxygen the molecule 02. Burning hydrogen and oxygen to get water is way easier to grasp when you understand it's not individual, unbound atoms catching flame and producing water. They are bound molecules that break apart and rejoin differently. And further, the why helps a lot too. H and O have electrons that need to bind to other atom's electrons or else they are unstable. You wouldn't just see a single oxygen atom hanging out. It's going to link up with other oxygen or other atoms. We don't breath O we breathe 02. Ozone, o3, in nature does recombine as o2. So if you had 2 ozone molecules they could recombine to be 3 oxygen molecules. The whole time there were 6 oxygen atoms, but they always partnered up with some buddies. Atoms just don't like being alone.
I really love that she's not dumbing it down all that much. She's displaying the complex beauty of chemistry so that people aren't misled into thinking that it's something other than what it really is.
Years ago, when my kids were kids, we had little accident which resulted in a huge grape juice stain on the counter-top. We spent quite a while 'trying to clean it' by alternating ammonia and vinegar. (for those who don't know, the stain changes colour back and forth, like litmus paper)
I love Chuck’s humor with the Tasmanian devil, Kate has really got to the nitty gritty with learning why PFAS are a danger in a multitude of ways! I thoroughly enjoyed this conversation Neil😊
Kate the chemist 😍 i can imagine how awesome her chemistry classes are. Such great energy. And Neil & Chuck, never ceasing to mk for a fun informative podcast. Thank you all.
I so very enjoyed this episode. Thank you all!! I feel like I learned so much! And at 54! Well everytime I watch Startalk I have a 🤯time!! Thank you… makes me wish I had pushed harder when I was in school!!
So cool that deGrasse had not only something she hadn’t heard of but also my absolute favorite thing Dulce de Leche- but i don’t know that we ever boiled the can for just one hour… i was taught by a Brazilian friend when i was young-late teen we would boil the can between 2 and 4 hours, depending on what we wanted it for; the longer u boil the thicker and more solid the caramel becomes, so only 2 hours to make a spread or dip for something like apples or pretzels, and 4 hours to make more ‘chewy’ caramel texture -i’ve even gone up to 5 hours to make chocolate caramel truffles; where we took scoops of the thick globs (after can cooled and was opened) and dipped into chocolate or ganache-another fun kitchen chemistry recipe to try btw- now i want to try just an hour- i imagine that would be really good on a kind of coffee cake or something… I’ve edited this many times as i was remembering, the time i did use, after a 2 hour boil, as a filling in a cake, but it didn’t quite drizzle and pour like he described
