It’s #NationalArtichokeDay! The antioxidant capacity of artichoke flower heads is one of the highest of any vegetable. They contain apigenin and luteolin, both long used as yellow dyes. Luteolin was first isolated in 1829 by the French chemist Michel Eugène Chevreul #272sci

It’s #NationalNachosDay! They’re often served with a smooth cheese dip—made by adding (tri)sodium citrate, or Na₃C₆H₅O₇, to cheese. It reduces the pH, makes the cheese proteins more soluble & prevents the mix separating.

Ignoring the numbers, its formula spells… 😄 #272sci

Since it’s #StressAwarenessDay: cortisol is a stress hormone, produced by the adrenal gland. It has many effects: it helps formation of short-term memories, but long-term exposure damages hippocampus cells, impairing learning. Trying to remember something? Try to relax! #272sci

Banana oil is isoamyl acetate in ethanol, used as a solvent & flavouring. The aircraft industry calls it “aircraft dope”—it was used to stiffen fabric surfaces. It’s a bee pheromone & “banana oil” is slang for nonsense, from which we get “that’s bananas” #272sci #BananaLoversDay

Mangos contain fatty acids (omega-3 and omega-6) and amounts increase as they ripen, which is partly why their flavour and texture changes. As with bananas, ethylene speeds up ripening—they’ll ripen quicker in a sealed container, slower if open to air #NationalMangoDay #272sci

Certain catsharks are biofluorescent—their skin absorbs blue light & emits green, orange and red, producing patterns other sharks can see. The molecules that do this also protect the fish from bacteria in sediment—they’re antimicrobial as well as glowy! #272sci #SharkAwarenessDay

Since it’s #WorldChocolateDay, did you know fat in chocolate crystallises? Type V crystals give the best snappy chocolate. Tempering is all about forming this types of crystal and not others. The best temp to store chocolate is ~16°C (so UK ambient temps are ideal!) #272sci

For #July4th, metal salts give fireworks their colours, but the bangs come from black powder (gunpowder), which is a mix of sulfur, carbon and potassium nitrate (KNO₃, also called saltpetre). It’s old chemistry: humans have been using gunpowder for at least 1200 years #272sci

It’s #InternationalAsteroidDay! Some companies hope to mine asteroids in space because it’s been speculated one 500m Pt-rich asteroid might have more platinum group metals (Ru, Rh, Pd, Os, Ir & Pt – rare on Earth but very useful) than ever mined on Earth in human history #272sci

It’s #NationalCameraDay! These days most people are using digital, but one important chemical in the development of film has been silver bromide, AgBr. Exposed to light, the silver ions are reduced to silver metal, which show up as dark areas, producing a “negative” image #272sci

It’s #NationalPralinesDay! Praline usually contains almonds, pecans & hazelnuts. Only one of these is a technically a nut: almonds & pecans are drupes (fleshy outside, shell around a seed inside). Hazelnuts ARE nuts, but most things we think of as nuts, aren’t! #272sci

It's #NationalOnionRingDay! The onion chemical that makes you cry is syn-propanethial-S-oxide. But onions don't contain it—they produce it when damaged. It's volatile and an irritant so, when it reaches your eyes, you release tears in response to dilute and flush it away #272sci

It’s #NationalVanillaMilkshakeDay! The main chemical that produces vanilla’s flavour/scent is vanillin (C₈H₈O₃). It was first isolated in 1868 (a lab that, for once, probably smelled nice). Some experiments have shown vanilla scent reduces stress & anxiety, so enjoy! #272sci

Foxgloves are flowering! They’re a source of the drug, digitalis, which affects the human pulse. It was historically used by herbalists, but it’s difficult to control the dose. Refined digitalis (from D. lanata) is still prescribed for patients with atrial fibrillation #272sci 🫀

It’s #NationalRedRoseDay. Rose pigments are complicated: one interesting substance is protocyanin, which produces reds in roses but blues in cornflowers. This was first thought be due to different pHs, but later turned out to result from the way the pigment complexes form #272sci

It's #WorldGinDay! Gin's distinctive flavour comes from juniper berries, which contain monoterpenes such as α-pinene – also found in pines, rosemary & eucalyptus – which is an acetylcholinesterase inhibitor, thought to aid memory. But drinking gin might not help there... #272sci

It’s #ChocolateIceCreamDay! Ice cream contains fat & water—how do they stay mixed? Lecithin (E322) is found in egg yolks & can also be synthesised. It’s amphiphilic—attracting both fatty & polar substances. This makes it an emulsifier, keeping everything evenly mixed #272sci

Water chlorination is essential to control waterborne pathogens, but swimming pools aren’t treated with chlorine (Cl₂) directly. Instead hypochlorites (NaClO, Ca(ClO)₂) are used, which react with water to form hypochlorous acid (HOCl). pH must be maintained at 7.2–7.8 #272sci

Silver is a popular jewellery metal, but it reacts with sulfur compounds to form a grey-black tarnish, Ag₂S. Perming & hair relaxing solutions contain ammonium thioglycolate which breaks & forms sulfide bonds in hair, so take silver jewellery off before the hairdresser! #272sci

Ladybirds (/bugs) have sticky feet. They secrete a fluid which contains hydrophilic (water-loving) & hydrophobic (water-hating) substances. On different surfaces, the molecules naturally organise to give the best possible adhesion, so the bugs never fall off!🐞#272sci

The pretty pink sand on this beach in Indonesia is caused by single-celled organisms called Foraminifera—particularly Homotrema rubrum—whose calcium carbonate shells are red because of photosynthetic pigments (not, as some have suggested, because of iron compounds) #272sci

It’s #WorldWhiskyDay (no E). Chemicals called lactones—ring-shaped molecules with COO ester groups—are found in the oak barrels used to age the spirit & provide woody, nutty flavours. Other esters provide fruity aromas, while smokiness comes from phenolic compounds #272sci

For #WorldBeeDay – plants produce ethyl oleate, which forager bees gather & feed to worker bees, where it keeps them in a “nurse bee state” so they don’t mature into foraging bees too early. As foragers die, there’s less ethyl oleate, so more nurse bees mature 🐝
#272sci

It’s #WorldBakingDay. Baking powder and baking soda are different things: baking *powder* is a mixture of a (bi)carbonate & a weak acid (commonly cream of tartar, KC₄H₅O₆) with other substances. In the baking mix, the two react to form CO₂ bubbles, & the cake rises #272sci

For #NationalBarbecueDay: charcoal is carbonised wood, made by heating wood strongly in limited oxygen (in a charcoal burner) to remove water & volatile substances. One kg charcoal contains ~0.7kg carbon; it’s lighter than wood & burns with a very hot & fairly clean flame #272sci

Bronze disease is irreversible corrosion that happens when copper-based alloys (brass, bronze) come into contact with Cl⁻ ions in, eg, salt water. CuCl forms which reacts further to form cupric hydroxide/cupric chloride and HCl, which further reacts to produce more CuCl. #272sci

Bananas contain isoamyl acetate, an ester with a distinct banana-y scent. Modern bananas don’t have so much as those from pre-1990s, but it’s still there. It’s also an alarm pheromone for bees, so don’t eat bananas near a hive – you might get attacked #272sci 🍌 🐝 #Eurovision

Alkaloids are naturally-occurring organic compounds that contain at least one N atom. They often have effects in the body—cocaine for example, extracted from coca leaves (Erythroxylum coca), is a stimulant and euphoriant that produces feelings of excitement and pleasure #272sci

It's #MotherOceanDay. CO₂ dissolves in the oceans—the equation is:

CO₂ + H₂O ⇌ H₂CO₃

H₂CO₃ is carbonic acid. The pH of the ocean (at the surface) is currently ~8.1, but it's predicted to become more acidic—bad news for coral & creatures with carbonate shells #272sci

Speaking of rosemary, it contains camphor—a natural plant insecticide with the formula C₁₀H₁₆O that has a characteristic, strong scent. In the early days of plastic production, camphor was used as the plasticiser to make celluloid from nitrocellulose #272sci