I have never been able to float very well, often after a matter of seconds my stomach caves in and i sink.  Recently on a hot day I had several beers before floating in my backyard pool.  I could suddenly float.

Why?  Is it something to do with the beer in my stomach or blood or simply me being more relaxed and thus making it easier to float?

Some decades ago I was travelling around Australia and was lucky enough to climb Uluru. Pools on top of the rock had been produced by recent rain and, curiously, in many of them strange aquatic invertebrates were present (see photo).

This specimen is sitting in my camera lens cap, which has a diameter of 62 millimetres. It looks like an ancient trilobite. Why and how was it on top of the famous, massive rock, and what is it? What happens to the creatures when the short-lived puddles dry up?

Gavin Chester, Dwellingup, Western Australia