Why Can a Sand Dune Sing More Than One Note?
Sorting grains made noisy singing sand produce a clearer note. Laboratory avalanches reveal what grain size contributes to a dune’s sound.
How Do We Know Vikings Cut Wood in America in 1021?
A radiocarbon spike and preserved tree edges date Norse woodcutting in Newfoundland to 1021, without establishing the first arrival.
Why Does Popcorn Jump, and What Makes the Pop?
High-speed recordings separate popcorn’s bursting hull, starch-powered jump, and sound. The pop is best explained by escaping water vapour.
How Can We See a Supernova Again Centuries Later?
Light echoes let astronomers recover an old supernova’s spectrum and use its radiation to map interstellar dust in three dimensions.
How Can Antarctic Icefish Live Without Hemoglobin?
Antarctic icefish use dissolved oxygen and a remodeled circulation to live without hemoglobin. Their genomes reveal clues to how the genes vanished.
How Can You Speak Across a Valley by Whistling?
Whistled speech preserves selected sound cues so trained listeners can understand an existing language across a valley.
How Can a Möbius Strip Have Only One Side?
A half-twist joins the front of a paper strip to its back, making one continuous side. Tracing and cutting reveal exactly how it works.
Why Does Egg Tempera Paint in Tiny Strokes?
Egg tempera dries quickly, so painters build smooth-looking forms with fine strokes, prepared tones, and thin layers rather than prolonged blending.
