The Screams Over Your Head (Physics Level 8)
Show notes
We're going to work out exactly what a sound has to be for your ears to catch it, and then why bats deliberately make the ones you can't. By the end you'll be able to calculate how small a bat's sound waves are, using one short formula.
The scream you can't hear is the bat's whole strategy. Push the frequency up past the edge of human hearing and the wavelength shrinks to the size of dinner. You can now prove it with v = fλ: 343 ÷ 100,000 is about 3.4 mm.
Sources:
- https://tractian.com/en/glossary/speed-of-sound
- https://en.wikipedia.org/wiki/Bat_detector
- https://en.wikipedia.org/wiki/Bat_species_identification
- https://cdn.bats.org.uk/uploads/pdf/Resources/Welsh-EdPack/05-Echolocation-Eng.pdf?v=1551107156
- https://arxiv.org/pdf/2407.15318
- https://www.vigienature-ecole.fr/en/node/102
Source: Episode 4 - Physics Level 8, Waves and Sound (4/17)
Style: Exam prep
Length: 1118 words, 7 min target
Generated: 2026-10-25