Icebergs are large pieces of freshwater ice floating in open water. Icebergs are “born" when they break off from glaciers or ice shelves in a process called “calving."

Most of the glaciers that calve icebergs can be found along the shores of Greenland. Approximately 10,000 to 15,000 new icebergs break off from these glaciers each year.

Icebergs come in all shapes and sizes. Icebergs the size of a house are considered small.

Icebergs can be much, much bigger. Some icebergs can be as big as an airplane, a building or even an aircraft carrier! The tallest iceberg on record was about 550 feet tall.

So how big does a chunk of ice have to be to be called an iceberg? By definition, icebergs must extend out of the water at least 17 feet and be at least 50 feet long.

As they melt and become smaller, they are sometimes called “growlers" because of the animal-like sounds they make when trapped air escapes as they melt.

While ice cubes floating in your soda seem safe enough, icebergs floating in the ocean can actually be quite dangerous to ships. In fact, an iceberg was responsible for one of the worst maritime disasters of all time.

On the night of April 14, 1912, the RMS Titanic was crossing the North Atlantic when it collided with an iceberg. Although the ship's lookouts had seen the iceberg with enough advance warning to avoid a head-on collision, the ship still struck the portion of the iceberg that was underwater.

The iceberg punctured the ship's hull in several places, allowing water to fill several compartments and compromise the ship's ability to remain afloat. The Titanic sunk early the next morning, resulting in the loss of 1,517 passengers.

The Titanic had been considered “unsinkable" by some because of its advanced design, many safety features and immense size. Despite its impressive construction, it turned out to be no match for the iceberg it encountered that fateful night.

The sinking of the Titanic led to the establishment of the International Ice Patrol, which still patrols the North Atlantic today to keep a lookout for icebergs that might endanger ships at sea.

The iceberg that sank the Titanic was probably extremely big. However, big icebergs are not necessarily more dangerous than smaller ones.

While big icebergs are usually easier for ships to see, smaller icebergs can hide in the ocean's waves, making them harder to spot and thus much more dangerous.

If you've ever heard the phrase, “just the tip of the iceberg," you might be surprised to learn there's a lot of truth to it. People use the phrase to mean that what you can see is not all there is.

That's literally true for icebergs. The higher they extend above the water, the deeper their bases extend below the water. For most icebergs, the part below the water is three to nine times the height above the water.

Despite the danger they pose to ships, icebergs play a key role in nature's water cycle. As icebergs melt, their water evaporates into the air and forms clouds.

The wind carries some of those clouds over Greenland, where the cold air causes moisture in the clouds to condense and fall as precipitation in the form of snow. Snow builds up on Greenland for thousands of years, forming glaciers.

Gravity forces these massive glaciers toward the sea. As they reach the ocean, the glaciers begin to break off into pieces and fall into the ocean, creating icebergs. As the icebergs travel and begin to melt, the process starts all over again!

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