Mer-children all.

Iris also likes water. She loves to gaze at it, watching fish swim or seaweed drift is particularly fine, but any combination of water and movement will do. If she's quenched her most desperate thirst she'll find herself succumbing to an equally desparate urge to watch the water in her cup dripping, splashing, pouring.

Iris likes to go to sleep holding her sparkly light. It was was a birthday present, it's beautiful, safe, soporific, and scientifically interesting. The bottle part has glitter in the water and when it's tipped it starts a blue, a red and a green diode alternating for a minute or so. The glitter reflects the diodes' light as it slowly turns in the convection currents. She tips it, watches it and closes her eyes, tips it, watches it and closes her eyes, finally she can't be bothered opening her eyes or tipping it any more. My father does fluid mechanics, particularly of drops and bubbles, I wonder whether he too was fascinated by watching water when small.