So...Science experiments - water & ice

The other day we were left without electricity due to an incident at the power plant involving stolen cables and fire.  There were rumours it would be days before it would be restored and it was widespread.  So with a freezer full of perishables I rushed out and stocked up on ice to try keep our freezer cold for as long as possible.
Luckily the outage wasn't long lived and we were up and running that evening again.
Now I had a freezer full of ice...add two small children and you have another science experiment!

 We filled up two tubs with water - one hot and one cold (I coloured our cold water just for fun)
Then I put our a big tub full of ice, some sieves and just let them play.
Some observations:
The ice in the hot water melted faster than in the cold water
Ice floats
Even BIG blocks of ice float, although only certain bits stick out the water - like an iceberg
Our hot water got cold
Eventually we had lots of water and no ice

 The setup

 Adding ice to the tubs

 A big floating iceberg

Examining a teeny block of melted ice