Spot the odd sound frequency

Exercise and reference answers

Questions

1. Items

   1. Whisper (~30 Hz)
   2. Voice (~200 Hz)
   3. Bat call (~50 kHz)
   4. Bird call (~5 kHz)

   Reason

   Humans hear roughly 20 Hz – 20 kHz; bat ultrasonic calls at 50 kHz are inaudible.

   Odd item

   Bat call (~50 kHz)

Instructions

Each card shows a sound and its frequency. Tap the one that does not belong with the others.