H2O from A to Z. Everything you ever wanted to know about water. Small and quiet, but it's free and fun enough to justify popping in if you are nearby.

As with most museums in Japan, considerable thought and money has obviously gone into the design of the building - in this case an airy central atrium ringed by three floors of exhibits. A huge blue sculpture dangles from the ceiling, no doubt representing something watery. The inevitable piped music tinkles, ripples and plops like a soundtrack from a 1970s underwater documentary. Was it my impression or were the arrows pointing to the toilets especially prominent? The "relaxation room" with its bubble-tubes and water-show certainly had me crossing my legs within seconds.

The exhibits are mostly hands-on; kids are going to enjoy the giant soap-bubble maker and the various science experiments. There's a virtual reality white-water rafting theater and displays on various special uses of water like jet cutters and shake control systems. The museum actually sits on top of the Ariake water supply station and you can take a 30-minute tour down into the basement to look at the pumping rooms and monitoring rooms.

One nice enough way to pass a wet Sunday afternoon.