Temple tank.

About Temple Tank

What happens

• The water follows the real physics of ripples. Longer ripples travel faster than shorter ones, so a single pebble spreads into a train of rings.
• You see the steps through the water bent by refraction, the way real water bends light. The curved surface focuses sunlight into the bright net on the bottom (caustics).
• Water absorbs red light first, so the deeper steps look greener. The sky and the gopuram (temple tower) show only where the surface tilts toward them.
• A pebble’s plop is the air bubble it traps ringing: a smaller pebble makes a higher note.

The Chennai bit

• At temple tanks people throw pori (puffed rice) to the fish. Hold still on the water to try it.

Inspired by The Kapaleeshwarar temple tank, Mylapore, Chennai, India.