Explorez tous les épisodes du podcast The History of Chemistry
| Titre | Date | Durée | |
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| 135: Bond, Chemical Bond | 25 Aug 2024 | 00:22:42 | |
In which we consider what, really, is a chemical bond. Lewis and Langmuir promoted the idea that bonding was sharing of electron pairs. Then we hear about Slater, Hellman, and Ruedenberg's discussion of how covalent bonding works. Kossel and Lewis also introduced ionic bonding. Finally Drude and Lorentz offered metallic bonding. But there are more chemical bonds: the hydrogen bond, the halogen bond, the mechanical bond, the van der Waals force, multi-center bonds, and metallophilic bonds.
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| 134: Atto-boy! | 18 Aug 2024 | 00:19:27 | |
In which we talk about the fastest spectroscopy yet, attosecond spectroscopy, which can resolve electrons moving around atoms. The topic begins with Christian Spielmann in 1997, working to get shorter and shorter laser pulses, and continues with Ferenc Krausz. We discuss what you might be able to inspect using these short light pulses, such as how the shape of atomic orbitals oscillates after ionization, how you can change the opacity of a substance for a brief moment, and fluctuations of water structure.
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| 125: Das Model | 16 Jun 2024 | 00:23:29 | |
Here we discuss all sorts of kits chemists use to build models of different molecules. We start with the pre-molecule set built for John Dalton, and then we hear of August von Hofmann's set for lecture demonstrations. We talk of John Dewar's brass constructions, and then to Tinkertoy-like setups in the 20th century. Plastic first appears in molecular-model kits by the 1950s, and we continue through the later 20th-century. If you become a Patreon subscriber, you may download a supplemental sheet which shows some 20th-century kits, including a lecture demonstration kit I don't discuss in this episode!
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| 35: Au Pair | 26 Oct 2022 | 00:24:34 | |
We learn of the various quantum numbers that describe the size and shape of the energy levels that electrons have inside atoms. Then Louis de Broglie proposes that, just as light has particle characteristics, matter (including electrons) have wave characteristics, which Davisson, Germer, and Thomson show is true. From this, we find that electron waves can fit around atoms only in certain energies. Heitler and London model the smallest molecule, dihydrogen, using quantum-mechanical principles. Linus Pauling takes some general ideas from quantum mechanics, and applies them to chemical bonding.
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| 34: Plastic Fantastic | 20 Oct 2022 | 00:21:26 | |
This episode introduces us to the first attempts at "plastic materials" in the 19th century, from vulcanized rubber by Charles Goodyear and Thomas Hancock, to Alexander Parkes's "Parkesine", the first synthetic polymer. Later polymers of the Victorian era include Celluloid, rayon, photographic film and the rise of easy photography, the mostly forgotten charmer of the Art Deco word called galalith, Bakelite, and cellulose acetate--also called Celanese. Among the chemists we meet are John Hyatt, George Eastman, Louis Bernigaud, Wilhelm Krische, and Leo Baekeland, and Camille and Henri Dreyfus. But even with these developments, chemists still weren't sure what a polymer really is.
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| 33: I Want a New Drug | 14 Oct 2022 | 00:22:08 | |
We learn about the successes in finding structures for biochemical compounds like chlorophyll, steroidal molecules and bile acids, cholesterol, vitamin D, and bufotoxin. Other vitamins which were analyzed were vitamin A and vitamin B6. B6 has a pyridine structure. Chemists came to understand terpenes, found in places like pine trees. The blood molecule hemin has a similar structure to chlorophyll. Alkaloids and then the building blocks of DNA, the bases, were given structures.
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| 32: Shell Game | 09 Oct 2022 | 00:22:42 | |
Charles Barkla realized how electrons arrange themselves in shells around atoms. Gilbert Lewis noted how electrons can pair up and form bonds, without (much) regard for willingness to give up or accept other electrons to complete shells. We discuss polarity of molecules. Irving Langmuir promoted and expanded Lewis's ideas, adding that atoms like to form octets. Finally, we discuss various models of acidity and basicity.
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| 31: What's Inside | 03 Oct 2022 | 00:26:13 | |
Ernest Rutherford discovered the basic structure of the atom. Then Max von Laue suggested diffracting x rays through crystalline layers and showed that atoms have a particular arrangement in crystals. Henry Moseley found a relationship between scattered x rays off elements and the positive charge in their nucleus, thus explaining the Periodic Table. Then Max Plank upended science with his "quantum theory". Niels Bohr used quantum theory to posit electron levels in atoms.
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| 30: X ray Vision | 28 Sep 2022 | 00:23:42 | |
Wilhelm Konrad Röntgen made an earth-shattering discovery for chemistry and atoms in 1895: He discovered x rays. Then, soon after, Henri Becquerel took the idea of x rays a step further and made another, equally earth-shattering discovery for chemistry and atoms: radioactivity. The Curies figured out which known elements were radioactive. Rutherford categorized radioactive rays into alpha, beta, and gamma. We explore what these rays are. We end up with the discovery of the neutron.
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| 29: Electrons | 21 Sep 2022 | 00:23:30 | |
We finally reach the discovery of electrons. The path starts with experiments on electricity in small vacuum vessels and vacuum pumps, improved by Heinrich Geissler, further improved by William Crookes, and then proving that their mysterious cathode rays were matter, not light, responding to electric and magnetic fields and possessing a mass, as J.J. Thomson showed. Robert Millikan determined the actual mass of the electron. We hear about Thomas Edison's strange electrical effect, and Heinrich Hertz's photoelectric effect. Finally we end with a variety of possible models attempting to explain the structure of atoms.
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| 28: A Nobel, Booming Business | 16 Sep 2022 | 00:20:57 | |
In the 19th century, the centuries-old dependence on gunpowder for war began to change with Christian Schönbein's invention of guncotton. Then Sobrero invented the frightening nitroglycerin. We learn about Alfred Nobel's dealings with nitroglycerin and his efforts to improve its stability. We also hear about his will, founding the Nobel Prizes. There are more variations of nitro compounds, such as TNT.
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| 27: Salt of the Earth | 09 Sep 2022 | 00:24:36 | |
We examine industrial inorganic chemistry of the 18th and 19th centuries, including sodium carbonate, focusing on the Leblanc Process and its replacement, the Solvay method. We look at production of the number one chemical in the world, sulfuric acid. We discuss the superphosphate process for fertilizer, and the invention of the match. Steel was a major factor in the Industrial Revolution, so we examine a variety of alloys. Aluminum's expansion with the Hall-Héroult process is mentioned. Finally we talk about the element fluorine and silicon carbide.
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| 26: Color Me Synthetic | 04 Sep 2022 | 00:26:16 | |
We look at the synthetic dye industry of the 1700s and 1800s, starting with Johann Diesbach, who invented Prussian blue in around 1706. Peter Woulfe found picric acid, a brilliant yellow compound, to be an effective dye for silk and wool in 1771. We hear the words of Dr. Jim Brazell, Professor Emeritus of English at The College of New Jersey, on early 19th-century literature by the German polymath Goethe dealing with chemistry. By the 1850s, William Perkin stumbles upon mauveine, and sent the Victorian Era crazy for mauve fashions. Baeyer discovers how to synthesize indigo dye, and Graebe and Libermann do the same for alizarin dye.
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| 124: Lumen Large | 09 Jun 2024 | 00:20:39 | |
Our history of LEDs continues with the entry of LEDs into commercial lighting. We talk of different ways to get white light out of LEDs, and materials for white-light LEDs. We briefly discuss color temperature because there are different kinds of white. Then we hear of the publication of an article in 2000 that consolidated thinking about home usage for LEDs, and why LEDs have advantages over other lamps. We mention ways geometrically to optimize LED construction to maximize the amount of light emitted. Finally, we note the development of second-generation emitting compounds in red, green, and blue that pushed LEDs over the finish line to make them practical for home usage.
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| 25: Seeing the Light | 29 Aug 2022 | 00:19:18 | |
In this episode we review 19th-century photochemistry, particularly photography, as well as chain reactions catalyzed by light. We finish up with boiling-point elevation, the last of the "colligative properties." With these aspects of physical chemistry, 19th-century physical chemistry gelled into a full chemical field, and the journal Zeitschrift für Physikalische Chemie was born.
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| 24: Free Energy | 23 Aug 2022 | 00:27:45 | |
Josiah Gibbs revolutionized physical chemistry with his mathematics of thermodynamics and chemical equilibria, but published in an obscure journal few read. Wilhelm Ostward explained catalysis with his idea of an intermediate. Einstein figured out the cause of Brownian motion, and gave sufficient proof of atoms and molecules that all scientists accepted atomic theory. These developments led to the journal Zeitschrift für Physikalische Chemie, which still exists today. Arrhenius's ionic dissociation explained many of water's properties, and led eventually to Søren Sørensen's pH designation of acids and bases. Guest, Vincent Falcone, Head Brewer of City-State Brewing in Washington, DC, discusses pH and beer.
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| 23: Ionic but not Doric nor Corinthian | 17 Aug 2022 | 00:20:19 | |
The Maxwell-Boltzmann distribution explains the behavior of gases nicely, and went well with the Ideal Gas Law of Clapeyton, until van der Waals modified the Ideal Gas Law a bit. We learn about absolute temperature and Lord Kelvin. Van 't Hoff connects the gas laws to osmotic pressure and ionic solutions. We hear of Raoult's Law and freezing-point depression. Finally we arrive at Svante Arrhenius's (barely passing) doctoral dissertation on ionic dissociation, and his activation energy for reactions.
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| 22: Hot Stuff | 11 Aug 2022 | 00:25:07 | |
We begin to examine 19th-century physical chemistry with thermodynamics. We hear of Rudolf Clausius and the two Laws of Thermodynamics, as well as entropy. There is Hess's Law, and Berthelot's calorimeter. We hear how Alexander Williamson started the field of chemical kinetics. Waage and Guldberg propose the Law of Mass Action, which tells us what concentrations of chemicals are at equilibrium.
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| 21: The Periodic Prophet | 05 Aug 2022 | 00:25:32 | |
We learn about the development of spectroscopy by Bunsen and Kirchhoff, and its ramifications, like remote sensing of materials--including heavenly bodies. We also learn about new elements discovered by spectroscopy, which boosted Mendeleev's periodic table and earned him accolades. Mendeleev, however, also predicted elements that don't exist, and failed to anticipate an entire classification of elements found in the 1890s by William Ramsey. Writer H.G. Wells even included one of these elements in a world-famous sci-fi novel.
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| 20: The Element of Surprise | 31 Jul 2022 | 00:22:32 | |
The problem of the large and growing variety of elements perplexed chemists, who attempted to bring order to the chaos. We learn about Döbereiner's triads, Pettenkofer and Dumas's correlations of multiples of atomic weights, Newlands's Law of Octaves, and Chancourtois's Telluric Screw. Kekulé's Karlsruhe conference brought order to some chemical chaos, and was the launching point for Dmitri Mendeleev and his periodic table, while Lothar Meyer almost beat Mendeleev for bragging rights. Mendeleev's close friend Alexander Borodin was a chemist AND composer, and we hear from guest Alan Rothenberg on Borodin's life and music.
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| 19: Molecules in 3D | 25 Jul 2022 | 00:22:55 | |
...in which we learn how polarized light helped Louis Pasteur to determine that internal three-dimensional structure of molecules was real based on "optical isomers." We then move to the 1870s, and see how van 't Hoff and Le Bel independently came up with the idea of tetrahedral carbon to explain optical isomers. Once the idea of an actual 3D structure for molecules was accepted, a variety of chemists used this idea to explain all sorts of molecular structures. Supporters of this podcast at https://www.patreon.com/thehistoryofchemistry can download a supplementary sheet with some diagrams.
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| Bonus episode: Behind the Scenes | 19 Jul 2022 | 00:11:05 | |
This episode explains how I create each episode of the podcast, from researching, to script-writing, recording, and editing.
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| 18: Ouroboros | 19 Jul 2022 | 00:19:46 | |
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| 17: Electrochemistry | 13 Jul 2022 | 00:20:09 | |
We learn about Jane Marcet, one of the most popular science writers of the 1800s, and her connection to Michael Faraday, one of the most brilliant experimental scientists and demonstrators of the 1800s, as well as Faraday's investigations into electrochemistry. Faraday asked Reverend William Whewell for electrochemical terminology. We hear about the development of electric batteries, electroplating, and how a German soldier imprisoned for a duel founded an international electronics firm.
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| 123: Setting the Ground Rules | 02 Jun 2024 | 00:21:51 | |
This episode gives a basic review of geochemistry, starting with pioneers such as Christian Friedrich Schönbein, Frank Wigglesworth Clarke, and thence into the 20th century, especially Victor Goldschmidt. We hear about the development of geochemical societies around the world, then we talk about various subfields of geochemistry. The question of "what's inside the Earth" is still a very active one, and we discuss ways to simulate the pressure inside the Earth, and likely constituents of the Earth's core.
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| 16: You're Not My Type | 08 Jul 2022 | 00:23:18 | |
We learn about radical theory and type theory in organic chemistry of the 2nd quarter of the 19th century, and the battle between old stalwart Berzelius and the upstart chemists Gerhardt and Laurent. There is a bit of political history from Japan, the Chōshū Five, and their intersection with English chemistry professor Alexander Williamson.
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| 15: It's Organic | 01 Jul 2022 | 00:28:30 | |
We reach the beginning of the branch of chemistry called Organic Chemistry. How did organic chemistry differ from inorganic chemistry? Can chemists make organic compounds, or is that restricted only to living creatures? We learn about Friedrich Wöhler, and of Berzelius's theory of radicals, and the problem of isomers.
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| 14: Berzelius | 26 Jun 2022 | 00:16:29 | |
In which we discuss Jöns Jakob Berzelius and his work. We also take a short detour to hear what US Presidents John Adams and Thomas Jefferson thought about chemistry. We mention the first female Swedish chemist, Anna Sundström. We continue with the conundrum of atomic weights, but the rule of Dulong and Petit helps this to a degree.
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| 13: Up and Atom! | 20 Jun 2022 | 00:25:53 | |
John Dalton, a Quaker from northern England, was a color-blind scientist. He presented his atomic theory that finally began to make sense to natural philosophers. He also invented a series of symbols for the elements, and created the first table of atomic weights. We learn about Joseph Prout's unusual atomic idea, and Gay-Lussac's work with gases that meshed with atomic theory. Then Alessandro Volta invented the electric battery, which allowed Humphry Davy to find new elements.
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| 12: Revolution’s Aftermath | 14 Jun 2022 | 00:21:22 | |
What happened to Joseph Priestley and Marie-Anne plus Antoine Lavoisier? What were the immediate effects of Lavoisier’s new chemistry? We discuss how quickly the new chemistry was accepted, with some evidence in Elizabeth Fulhame’s book, plus the controversy between Berthollet and Proust over chemical composition of substances.
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| 11: Love is Like Oxygen | 08 Jun 2022 | 00:32:44 | |
We continue with research by Joseph Black, Henry Cavendish, and Joseph Priestley, concerning new "airs". Then there is the work by Karl Scheele, which was delayed being published, and Mikhail Lomonosov, which was generally ignored. Finally we reach Marie-Ann Paulze and Antoine Lavoisier, who created modern chemistry by realizing that phlogiston is bogus and water is not an element. We have a guest speaker, Dr. Martin Rosenberg, on the scientific art of Joseph Wright of Derby and a Jacques-Louis David's massive portraits of the Lavoisier couple. For links to images referred to by Dr. Rosenberg, become a Patreon supporter at https://www.patreon.com/thehistoryofchemistry
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| 10: Phlogiston: A Burning Question | 03 Jun 2022 | 00:23:15 | |
Here we see the advent of the steam engine, using the knowledge of Boyle's Law, invented by Thomas Savery. We encounter Johann Joachim Becher, with his three elemental earths, including a fatty earth that burned. Then we learn of Georg Ernst Stahl, and his popular idea of phlogiston as the burning quality--but it explained corrosion and rust, too! There is the new calibrated tool, the thermometer, which led to Joseph Black's research on gas sylvester. We discover that at this time, alchemy and chemistry finally diverge, never to meet again. Finally, we hear about the effect of the current natural science even on poetry and music, as performed by Dov Rosenschein.
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| 9: The First Chemists—Or Chymists? | 29 May 2022 | 00:20:32 | |
In which we meet Angela Sala, who first described accurately a chemical synthesis, van Helmont and his research into gases, Torricelli and his barometer, and Robert Boyle, the "Sceptical Chymist", with a new definition of an "element." We meet one of the last alchemists, Hennig Brand, and learn what he discovered.
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| 8: The Decline of Alchemy | 24 May 2022 | 00:18:17 | |
The Age of Discovery included new science, but alchemy still lingered. We meet the scholars Agricola, Biringuccio, Paracelsus, and more, along with their writings. We learn of the discovery of Glauber's salt, van Helmont's biochemistry experiment, and Sir Francis Bacon, with his method of scientific induction.
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| 7: European Alchemy | 19 May 2022 | 00:22:13 | |
As Europeans interacted more with Arab traders, many more books of ancient and Arab alchemy filtered into Europe. We learn about advances in glass, discovery of alcohol, gunpowder, mineral acids. We discuss a number of famous European alchemists and philosophers, and the practice of iatrochemistry.
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| 122: Catch the 'Wave | 26 May 2024 | 00:20:15 | |
Even though the potential for using microwaves to do chemistry was there since 1946, it wasn't until the late 1970s that the first use of microwaves in the chemistry laboratory appeared. This episode covers the development of microwave chemistry from moisture analyzers to significant study of reactions, and then finally laboratory-standard microwave ovens appeared. We mention the controversy between Gregory Dudley and Oliver Kappe as to whether there were some special properties of microwaves that made reactions speed up. We talk of the reasons that chemists now preferentially zap their reactants with microwaves over traditional chemical methods.
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| 6: Arab Alchemy | 13 May 2022 | 00:17:43 | |
This episode continues with the fall of the Roman Empire, sending the practitioners of Khemeia eastward. We learn of the rise of Arab Alchemy, the source of the word alchemy, and some of the major Arab alchemists: Geber and Al-Razi, We hear about the two major types of alchemy: exoteric and esoteric. There was a parallel development of alchemy in China as well.
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| 5: The Rise of Khemeia | 09 May 2022 | 00:17:42 | |
We talk about the rise of the mystical Egyptian art, "khemeia," in the Hellenistic Period through the Roman empire.
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| 4: It's Elementary! | 09 May 2022 | 00:20:20 | |
We discuss the first chemical theories, both Chinese and Greek, from ancient times, and some of the philosophers who argued about them.
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| 3: Metallica and More | 09 May 2022 | 00:21:46 | |
We discuss the earliest historical practical chemistry, such as bronze, smelting iron, leather-working, mummification, salt as a preservative, dyes, soap, and even the ultimate origin of the word "chemistry". We have a special guest, Biblical Hebrew scholar Michael Carasik of the podcast "Torah Talk" to fill us in on a bit of chemistry in the Hebrew Bible.
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| 2: All Fired Up | 07 May 2022 | 00:17:03 | |
This episode discusses examples of chemical change known to prehistoric humanity, from fire to fermentation, from annealing and smelting copper to glazing pottery, from heating ochre to change its color to the first use of bronze.
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| Trailer to The History of Chemistry | 07 May 2022 | 00:01:36 | |
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| 1: Introduction to The History of Chemistry | 07 May 2022 | 00:19:04 | |
This episode discusses the general theme of the podcast, its scope (from prehistory to the present), who I am, and the format of the series.
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| 121: Let the Sun Shine in | 19 May 2024 | 00:21:42 | |
We talk about perovskite minerals and compounds, their discovery, and general crystal structure. Then we learn about how researchers gradually learned about their interesting electrical and optical properties. We hear of Tsutomu Miyasaka’s paper about building a solar cell using these perovskite minerals, and the sudden interest in making commercial, practical solar cells from perovskites. We delve briefly into the electronic orbitals in perovskites, the engineering aspects of building photovoltaic cells with them, and how their efficiency in generating electrical current has soared since they were first invented.
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| 120: Snap Judgement | 12 May 2024 | 00:20:39 | |
Click Chemistry came about as several researchers came to similar conclusions in parallel, but from different angles: Barry Sharpless, Morten Meldahl, and Carolyn Bertozzi. We hear about their research goals in the 1990s and early 2000s: to snap together smaller molecules in a reliable way, perhaps with pharmaceutical or biological experiments and results in mind. We learn of Sharpless's goals for Click Chemistry, which sometimes overlap with Green Chemistry.
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| 119: Tiny but Mighty | 05 May 2024 | 00:21:40 | |
We reach the point in our chemical history when microplastics were first recognized as a pervasive environmental pollutant. Visible plastic bits were first found by Edward Carpenter and K.L. Smith in the ocean back in 1972, and such detritus was confirmed all over the world's oceans over the next decades, resulting in the name "Eastern Garbage Patch" by 1997. Yet only in 2004 did Richard Thompson first study microscopic bits of plastic. In this episode we define a microplastic, and discuss various sources for microplastics. We talk of potential harm they do.
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| 118: Hold Tight, Stick Tight | 28 Apr 2024 | 00:24:28 | |
This episode deals with glues and adhesives, from prehistoric times to the present. We talk of prehistoric glue from tree saps, petroleum tar, animal glues, casein glues, albumin glues, and starch glues, all known in ancient times. Medieval knowledge added fish glue, and by the Renaissance we start industrial-scale adhesive factories. The 19th century brought rubber cement, mucilage, and library paste. We talk of 20th-century products like white glue, epoxy, polyurethane glues, super glues, glue guns, glue sticks, and even Post-It Notes.
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| 117: The Set Table | 21 Apr 2024 | 00:23:38 | |
The Periodic Table we've all seen in chemistry books and classes is not always the way it was, nor the way it must always be. In this episode we explore all kinds of periodic representations of the properties of elements, from Mendeleev's first published table in 1869, through wide and narrow tables, and spirals. There are even three-dimensional "tables," from helices to submarines, corners of walls, globes, pyramids, and tiles. My Patreon subscribers can download a supplemental sheet with a few samples of periodic tables which I discuss.
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| 116: Open Frame of Mind | 14 Apr 2024 | 00:19:17 | |
We introduce the first chemical construction set in chemistry (besides natural proteins, starches, sugars, etc.), the metal-organic framework. A DuPont employee, E.A. Tomic, invented this type of molecule in the 1960s, but it took until Omar Yaghi's research in 1990s until chemists realized the value of metal-organic frameworks. We discuss the experiments and results leading up to Yaghi's work, what these frameworks are, their value in science and industry, and their nearly infinite flexibility to create porous materials.
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| 133: A Horse of a Different Color | 11 Aug 2024 | 00:20:51 | |
Instead of molecules that absorb light based on their molecular orbitals, this episode talks of nanostructures and their materials that refract light based on interference of light waves. We start with Robert Hooke who described this process in his book Micrographia. We continue through Isaac Newton and Lord Rayleigh. We discuss Eli Yablonovitch's photonic crystals. We mention various kinds of natural structural colorants in the living and non-living worlds, from minerals to insects to bacteria to plants. Then we list several attempts to synthesize structural colorants, and why they might prove useful.
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