The gravity tank is an amazing exhibit. Basically it is an ordinary fish tank of any size where the visitor can put their hand in with the fish through the middle of the tank. In spite of the fact that there may be four or eight foot of water over where you place your hand the water does not come flooding out.

I have spent a couple of hours watching peoples reactions to this exhibit. Many pass by without a glance. Others stare and try to figure it out and the clever ones are both amazed and fascinated. In Underwater World in Pattaya there is no supervision of the tank so it gets less attention. People put their hand in and the fish nibble their fingers. In Dalian, China visitors were allowed to feed the fish and so the tank got more attention.

I have lost count of the number of aquariums I have visited but have only seen this display in two. I would like to see more places using it because it is truly educational. It is not simply 'fish' and 'water' but science too.

And for those wanting to demonstrate the principles at home please see below for a demonstration. But please...give the fish a miss!