Why and how does ice insulate the liquid underneath it and prevent it (the liquid) from freezing?

Question

When a deep body of water cools, How and why do floating icebergs insulate the water below it and prevent the body of water from freezing?

Answer 1

The correct answer involves the density. As water freezes, it reorganizes it's crystalline/molecularb structure and becomes less dense (expands) when it freezes (which is why it floats in water. It displaces more water volume than it weighs). As a result, a less dense material conducts less heat, which means that in effect by slowing down heat transfer, it sort of insulates the water beneath. It isn't that ice is an insulator like a foam plastic substance, but that it simply resists the flow of heat more than liquid water does, which effectively insulates the water below by slowing the heat transfer rate, which is exactly what an insulator DOES.

Answer 2

The floating ice does provide insulation
from the colder air above, but the biggest
part of the effect of the ice is that it prevents
evaporative cooling.

Answer 3

Ice is a poor conductor of heat so it traps the warmth of the water below.