> Take a clean empty pop bottle to your local public swimming pool. Go to the entry
> ladder in the deep end and take the top off. Hold the bottle upside-down and push
> yourself just a couple of meters under the water. Now assuming that you can either
> a) see underwater or b) are wearing goggles, you will see that without leaking any
> air the water will be now well inside the bottle. The air has compressed at the depth.

Thanks, that is a great experiment indeed and I am going to try it. As a matter of fact I just finished cleaning the pool for the summer season...

wirelessguru1