Moonlit Tide Pool

What you can do here

Touch the pool

Tap the water and a ring spreads out across the pool, bends your view of the pebbles and anemones on the bottom, and bounces back off the rocks. Drag a finger through it for a small wake.

Wait for the sea

Every so often a swell comes through the gap between the rocks with a little foam, and a broad ripple rolls into the pool from its mouth. Raise the Tide and the swells come more often and run farther in.

Watch the moon path

The glitter on the open sea comes from the waves themselves: each small wave face catches the moon only while it is tilted just so. Breeze adds the smaller waves that make it sparkle, and ruffles the pool a little.

Catch the moon in the pool

The moon's reflection sits near the top of the pool. When a ring passes through it, the light breaks up into moving glints and then settles again.

Use it as your wallpaper

Press F for fullscreen and M to turn the sound off and on; the volume and your sound choice carry over to every wallpaper. The sound keeps playing if you switch to another tab.

Live link

On a computer desktop

Some wallpaper apps can show a web page behind your desktop icons. Give one the live link above and the scene runs there on its own: no page around it, no ads and no sound.

On a TV or a spare screen

Open this page and press F, or use Fullscreen. While it’s in fullscreen we ask the browser to keep the screen from going to sleep.

On a phone or tablet

Save image downloads exactly what’s on the screen as a picture. Set it as your wallpaper from your photos; the phone will crop the sides.

A live wallpaper keeps a page running all day. Through the live link the scene draws at most 30 frames a second and stops while the screen is covered, but on a laptop it still costs some battery.

Why moonlight makes a path

A calm sea would show the moon once, as a single reflection. Real water is covered in small tilted faces, and every one that happens to angle the moon toward you lights up for a moment. They can only do that in a band between you and the moon, which is why the glitter makes a path that points at you wherever you stand. Far off, the faces are too small to see one by one, so they blur into a smooth band of light near the horizon.

What lives in a tide pool

A tide pool is seawater left behind in the rocks as the tide goes out, topped up by waves and refilled at high tide. The red ones on the bottom here are sea anemones, animals that hold on to the rock and catch food with their tentacles. If you visit a real one, look without lifting stones, and put back anything you turn over the way you found it.

About the sounds

Two recordings: the tide moving through the rocks, and a single small splash for when you touch the pool. The splash waits three seconds between plays, as long as a ring takes to spread and settle, so tapping fast never piles it up.

If you’d rather just watch

• Moonlit Sea, a drawn moonlight screensaver
• Open Ocean, rolling waves drawn live