How reality gets edited on the way in. https://tricksofearandeye.com/ 2026-10-30T00:00:00Z https://tricksofearandeye.com/animal-senses/bat-echolocation/2026-10-30T00:00:00Z

In field recordings of 11 bat species in Panama, the strongest call frequency was above 20 kHz in every one. How loud the calls were, and how echoes give range.

Tricks of Ear and Eye https://tricksofearandeye.com/illusions/checker-shadow-illusion/2026-10-30T00:00:00Z

Squares 1 and 2 in this checker-shadow figure, drawn here from the principle, store the same gray level. Four competing accounts of why one can look lighter.

Tricks of Ear and Eye https://tricksofearandeye.com/instruments/clarinet/2026-10-30T00:00:00Z

A tube closed at one end resonates at 1, 3 and 5 times its lowest frequency. A clarinet is close to one, so its next register is about a twelfth up.

Tricks of Ear and Eye https://tricksofearandeye.com/sound/doppler-effect/2026-10-30T00:00:00Z

Five synthesized passes, 20 to 300 km/h: at a steady speed in a straight line, the frequency only falls. Listeners in a 1996 study still reported a rise.

Tricks of Ear and Eye https://tricksofearandeye.com/color/egyptian-blue/2026-10-30T00:00:00Z

Egyptian blue, a copper silicate with an earliest known use of 3300–3200 BCE, emits near-infrared light reported near 910 nm, past the CIE curve's 830 nm end.

Tricks of Ear and Eye https://tricksofearandeye.com/instruments/guitar-fret-spacing/2026-10-30T00:00:00Z

Fret positions for a 648 mm string: each gap is about 5.61% narrower than the last, and dividing by 18 leaves fret 12 of an ideal string about 12.5 cents flat.

Tricks of Ear and Eye https://tricksofearandeye.com/sound/helium-voice/2026-10-30T00:00:00Z

In heliox, a voice's source frequency barely shifts while its resonances rise. Two synthetic clips share a 120 Hz source; one has resonances 1.85 times higher.

Tricks of Ear and Eye https://tricksofearandeye.com/illusions/kanizsa-triangle/2026-10-30T00:00:00Z

Three notched disks, no lines. In a 1984 abstract, monkey area 18 cells responded to illusory contours; 2021 fMRI of 16 adults found activity rising along them.

Tricks of Ear and Eye https://tricksofearandeye.com/animal-senses/mantis-shrimp-eyes/2026-10-30T00:00:00Z

Some mantis shrimp have 12 kinds of color receptor, yet in tests they needed wavelengths 15–25 nm apart to tell them apart. Humans manage 1–8 nm.

Tricks of Ear and Eye https://tricksofearandeye.com/illusions/muller-lyer-illusion/2026-10-30T00:00:00Z

Equal lines, one usually judged longer: nine children responded to the Müller-Lyer illusion within 48 hours of gaining sight, as did blind people by touch.

Tricks of Ear and Eye https://tricksofearandeye.com/instruments/piano-hammer/2026-10-30T00:00:00Z

In a grand piano action, the jack lets go of the hammer just before the strike. Measurements on a grand show the hammer covering the last stretch on its own.

Tricks of Ear and Eye https://tricksofearandeye.com/animal-senses/pigeon-vision/2026-10-30T00:00:00Z

Pigeon vision: both eyes share about 20° in front; about 40° at the back is blind (2024 summary; values differ). Shortest cone: about 409 nm (1997 abstract).

Tricks of Ear and Eye https://tricksofearandeye.com/color/prussian-blue/2026-10-30T00:00:00Z

Prussian blue was announced in Berlin in 1710 and a recipe printed in 1724. The tale of a red that turned blue comes from Stahl's 1731 book, as Kraft traces it.

Tricks of Ear and Eye https://tricksofearandeye.com/sound/shepard-tone/2026-10-30T00:00:00Z

Clip 1 lifts each component of a Shepard tone a semitone 12 times, and tone 13 matches tone 1. Listeners in experiments tended to report the shorter way around.

Tricks of Ear and Eye https://tricksofearandeye.com/color/ultramarine/2026-10-30T00:00:00Z

Ultramarine's blue comes mainly from three sulfur atoms trapped in a mineral cage. How lapis lazuli fits in, and what 1828 reports say of the synthetic.

Tricks of Ear and Eye