The Bedtime Scientist

Episode guide

Tides: How the Moon Moves the Sea

Twice a day, the ocean breathes in and out, pulled by a moon it has never touched. This episode stands at the water's edge and watches the slow pull.

The science, gently

  • The moon's gravity gently stretches the ocean, making the bulges of water we call tides.
  • Most shores see about two high tides and two low tides each day.
  • Tide pools are little worlds that practice patience between visits from the sea.

Wonder together

  • What would you keep in your tide pool?
  • Where does the water go at low tide?
  • What else in your life comes and goes as reliably as tides?

Tonight's calm-down

Breathe with the ocean's rhythm: high tide as you fill, low tide as you empty. The moon will keep the big water moving all night so that you do not have to move at all.