Chemistry in pictures

Swiss artist Fabian Oefner created a stunning series of watercolors called “Millefiori” with the help of magnetism. He simply added bright watercolors on top of a small dish filled with an oozy black magnetic substance called ferrofluid—a mixture containing oil and nanoparticles of magnetic substances such as iron oxides. When Oefner runs a magnet under the dish, the nanoparticles get magnetized, pushing and pulling each other around such that the ferrofluid creates peaks (black ridges and dots poking out of the paint) and valleys (troughs holding the paint). Even in these small droplets, which are about 1 cm wide, the oil and water don’t mix, resulting in the division of the watercolors and oily ferrofluid. —Manny Morone

In a double-displacement reaction, two sets of ionic chemical pairs switch partners. The reaction of silver nitrate with sodium chloride forms a white solid because, although both starting materials are very soluble in water, silver chloride, one of the products, is mostly insoluble. As silver chloride forms, it crashes out of solution, clouding the liquid. Meanwhile, soluble NaNO₃, the other product, stays dissolved. Here is the full chemical reaction: AgNO3 (aqueous) + NaCl (aqueous) → AgCl (solid) + NaNO₃ (aqueous) This photograph is from a series of illustrated chemical demonstrations available at beautifulchemistry.net. —Craig Bettenhausen

Reader Kylie Jespersen bought this bismuth crystal at a Little America gift shop in Wyoming. “When I saw it, I was so excited and I knew I had to get one,” she says. “It was the very first pure element that I had found.” Bismuth’s stepped crystallization patterns, iridescent colors, affordable price, and low toxicity make it a popular start to many element collections. —Craig Bettenhausen