Nature Podcast How earthquakes and lightning help explain squeaky sneakers
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Feb 25, 2026 Shamni Bundel, a science reporter who highlights fast-breaking studies, and Orly Lazarov, a neuroscientist studying human hippocampal neurogenesis. They explore how tiny electrical sparks and earthquake-like pulses make shoes squeak, plus new evidence for adult hippocampal neurogenesis and its links to ageing and cognitive resilience.
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Opening Pulses Produce Shoe Squeaks
- Squeaks come from fast opening pulses at the frictional interface that lift and detach regions, traveling at or above the rubber's sound speed.
- High-speed video showed pulse repetition rate equals audible pitch and patterned ridges channel pulses into a single musical note.
Sole Pattern Controls Squeak Pitch
- Geometry of the sole matters: patterned ridges channel opening pulses into a single frequency, producing a clear squeak.
- Flat rubber without ridges yields multi-directional pulses and noise rather than a musical note.
Pressure Triggers Squeaks Through Tribocharging
- Increasing normal pressure doesn't change squeak pitch but influences pulse nucleation via tribocharging.
- Electrostatic discharge creates micro-explosions that nucleate an opening slip pulse, initiating the squeak.