"For most substances, the solid form of the substance is more dense than the liquid phase; thus, a block of pure solid substance will sink in a tub of pure liquid substance. But, by contrast, a block of common ice will float in a tub of water because solid water is less dense than liquid water. This is an extremely important characteristic property of water. "(the good old trusty wikepedia's take)
"If water were like other substances, ice should form on the bottom of lakes and ponds because water would becomes more dense and sink as it cools." (USA Today)
all substances, Ron.
And we should wonder and question - and take our questions on the path they lead us to....
for without questioning and wondering, we don't get to know anything at all.