The Bedtime Scientist

Episode guide

Steam Train: The Rhythm of Sleep

A steam train is a kettle with wheels and a heartbeat. This episode rides the night train and lets its rhythm do what rhythms do.

The science, gently

  • Steam engines work by boiling water; the pushing steam moves the pistons that turn the wheels.
  • The chuff-chuff sound is steam being released in time with the turning wheels.
  • Night trains once rocked whole carriages of sleepers across countries by morning.

Wonder together

  • Where would you want to wake up, if a train carried you all night?
  • Why are rhythms so good at making people sleepy?
  • What is the best train sound: the whistle, the chuff, or the clack of the rails?

Tonight's calm-down

Say a slow chuff... chuff... in your head, one per breath, and let the carriage of your bed rock a half-inch in your imagination. Destination: morning, arriving on time.