Are icebergs made of frozen saltwater?

This is a not a myth that’s widely discussed, just something that seems obvious. Icebergs are found in saltwater oceans, but they are actually composed of freshwater, not saltwater.

Icebergs come not from the ocean but from land – glaciers or ice sheets formed from frozen rain or snow over thousands of years. The edge of a glacier forms an ice shelf where it meets the ocean; sometimes the ice shelf breaks and a chunk of ice floats away. Icebergs range from the size of a car to thousands of square miles!

Why do icebergs float and not sink? Three reasons. First, water actually has a peculiar property – it is one of the few substances that is more dense as a liquid than a solid. Second, icebergs contain a lot of trapped air. Third, freshwater is less dense than saltwater.

Saltwater CAN freeze – sort of. “Sea ice” is composed of saltwater that has frozen, but it actually contains little or no salt – when water freezes it does not allow salt molecules to become incorporated in its crystal structure.

Bonus Fact #1: Approximately 90% of an iceberg’s total volume is underwater!

Bonus Fact #2: The iceberg that the Titanic hit formed in Greenland.