The phrase “tip of the iceberg” comes from a real fact about ice physics. Ice floats on water because frozen water is slightly less dense - about 91% the density of liquid water. That means an iceberg floats with about 10% of its mass above the waterline and 90% below.
When ships pass icebergs at sea, the visible portion looks like a chunk of floating ice - sometimes a small one, sometimes a small mountain. But underneath, beneath the water, sits a much bigger structure. This is why icebergs have always been dangerous to ships: the underwater portion can extend far wider than the visible tip and lie in unpredictable directions.
The most famous iceberg disaster, the Titanic in 1912, is a tragic illustration. The iceberg that sank the ship was estimated to be only about 50-100 feet tall above water, but its underwater portion stretched far beyond. The ship’s lookout spotted it too late, and the ship struck the hidden ice along the side, opening up massive damage below the waterline. Modern ships use radar and satellite tracking to avoid icebergs, but the principle is still the same: what you see is only a small fraction of what’s there.
