By Steve Cohen
4.5
3131 ratings
The podcast currently has 142 episodes available.
We start with the first chemical conspiracy theory from 1996, "chemtrails." Then we move to another popular chemical hoax, "alkaline water" somehow being healthy for you. Related to that are the bizarre "hexagonal water" and water memory ideas. Other creative pseudochemical hoaxes are denial of global warming and the gasoline pill, creating fuel from non-fuel with merely a pill in your liquid. There is the fun cryogenically-cooled audio cable hoax (if you are into high-fidelity audio). There was the truly harmful radioactive bed scandal in Korea. Finally I offer some clues to detecting such hoaxes and scams.
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A new material, the MXene, discovered in 2010, is the topic of this episode. We hear of its creation and derivation at Drexel University in Philadelphia. Then we learn of ways to create single layers, variations in materials, and new methods of synthesis of MXenes. Finally, we discuss the practical uses of MXenes.
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We finally get to discuss what the term "aromatic compound" means in chemistry, from Michael Faraday's report in 1825 of a new organic compound (we call it benzene), to von Hofmann's first use in 1856 (without defining it) of the term "aromatic". We examine the ensuing controversies and definitions of "aromatic compound," how people modeled molecularly and diagrammatically what that meant, and current discussions over the word. My Patreon supporters may download a supplemental sheet with molecular structures of some aromatic compounds I mention in the episode.
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Aerogels, those feather-weight materials, have a century-old history. We begin with Samuel Kistler, the inventor of the first aerogels, and move forward through time with loss of interest in them, then revival of interest in the 1970s. We learn about gradual improvements in their fabrication over time. Then we talk of their fascinating properties, and then their uses.
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Artificial intelligence, or AI, can be applied to chemistry, too. Here we discuss a brief history of AI, especially for chemistry, beginning with Djerassi's DENDRAL program. We talk of the current problems in chemistry to which AI is being applied over the last couple of decades. We also examine what is not doable (yet) in chemistry with AI.
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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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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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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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This episode concerns the phenomenon in organic chemistry of classifying a set of similar reactions by a single umbrella name. Most named reactions honor a person, but not always. We discuss the early history of named reactions from the 1870s onward. We then talk about the slant of named reactions towards white men, and away from other people, and even whether that can be a problem for minority and women chemists. Patreon supporters may download a supplemental sheet that sketches some of the reactions I mention in the episode.
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Polyfluoroalkyl substances, or PFAS, seem to be ubiquitous now in the environment and the news. In this episode I delve into why chemists found these compounds so fascinating and useful. Then I discuss some history of how the world finally learned how dangerous these compounds can be if used and disposed of improperly. Finally I talk of some possible methods chemists are currently researching on how to remove PFAS from the environment.
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The podcast currently has 142 episodes available.
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