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Chemistry and materials3–5 minAn ice cube floats in the water it came from, and freezing water can push against its container. Ordinary ice arranges water molecules differently from the liquid, connecting a microscopic pattern with a familiar change in volume.

Chemistry and materials3–5 minSlice an apple open and leave it on the counter, and the pale flesh soon turns rusty brown. Cutting the fruit breaks open plant cells, allowing an enzyme called polyphenol oxidase to react with oxygen in the air and phenolic compounds in the apple, a chemical defense mechanism that changes the fruit's appearance and flavor.

Chemistry and materials3–7 minTurning lead into gold requires changing the nucleus, not finding a clever chemical recipe. CERN reported measurements of lead nuclei losing protons in near-miss interactions at the Large Hadron Collider. Gold nuclei appeared, but their brief journey ended in accelerator hardware. The experiment separates “can the transformation happen?” from “can we manufacture a useful gold bar?”

Chemistry and materials3–5 minTurning maize into masa involves a transformation before the milling stage. In nixtamalization, maize is cooked and soaked in an alkaline solution, then rinsed and ground. The treatment changes the grain, connecting the texture of a familiar food with a distinctive processing method.

Chemistry and materials3–5 minA scratch can concentrate the effects of a load, while strengthening treatments try to make cracks harder to open at the surface.

Chemistry and materials3–7 minA diamond can resist a scratch and still chip from an impact. Those are different tests of a material. Hardness concerns scratching; toughness concerns resistance to fracture. A diamond’s crystal structure also makes some breaking directions easier than others, so one impressive score cannot describe every way a gemstone might fail.

Chemistry and materials3–5 minSome exceptionally pure quartz used in chipmaking becomes the container, rather than the chip. Fused-quartz crucibles hold molten silicon while a crystal is grown, so the materials surrounding that silicon matter too. This hidden role gives an ordinary-looking mineral a place in an extraordinarily demanding manufacturing process.

Chemistry and materials3–7 minClick a metal disk inside a reusable hand warmer and crystals spread through the liquid as the pack heats up. The click starts a change in a sodium-acetate mixture; it does not supply all that warmth. Explore where the stored energy came from and what resetting the pack requires.

Chemistry and materials5–7 minCalling spider silk stronger than steel leaves two questions unanswered: which silk, and what does stronger mean? A web contains materials with different jobs, and resistance to breaking, stretchiness, and energy absorbed before breaking are different properties.

Chemistry and materials5–7 minA new element may exist for only a tiny fraction of a second, leaving a chain of decay events behind. The story of element 113 shows why observing a candidate, connecting it to known nuclei, and receiving formal recognition are separate steps.

Chemistry and materials4–5 minMelt a bar of dark chocolate and let it cool on the kitchen counter, and it often sets with a dull, streaky gray surface and a crumbly texture instead of a glossy snap. Because the cocoa butter fat inside chocolate can solidify into six different crystal shapes, chocolatiers must 'temper' it, carefully heating, cooling, and stirring the chocolate so a desirable crystal structure predominates.

Chemistry and materials3–7 minIn a cyanoacrylate adhesive, small molecules link into polymers after initiation at the surface, rather than simply waiting for a solvent to evaporate. Permabond’s product documentation identifies surface moisture as a trigger. Curing and evaporation can both turn a wet-looking material into a firm bond, through different processes.