Cell phone under water

Hello,

While experimenting with a cell phone and a water tank, I've noticed the following:

If the cell phone receives the call while it is out of the water it still rings when placed under the water.
However, if the cell phone is already in the water when the call is being made there is no received signal and the cell phone doesn't ring.

Any ideas what can cause this?

Thanks,
Alex

 

I assume your phone is in a waterproof container for these experiments?

Water doesn't conduct RF very well.