Great Rolling Icebergs!
image from TripAdvisor
Beautiful blue and white icebergs float in the frigid waters of the oceans. Only 90% of an iceberg is what we see on top of the ocean. Here is what the full iceberg looks like:
Snow falls in very cold places where it does not melt - even in the middle of summer. This snow builds up level by level, turning to ice, and forming an ice shelf or glacier. Pieces of the glacier break off and float on its own in the water - this is called an iceberg. Like an ice cube in a glass of water, the top of the iceberg is seen above the liquid - the rest is underneath.
This is why icebergs can be so dangerous to ships. The sailors can see the top of the iceberg, but they do not know how big it is under the water. The RMS Titanic hit an iceberg and sank, even though they tried to steer around it.
image from Kids Encyclopedia Facts
This is believed to be the iceberg that sunk the RMS Titanic. One side of the iceberg had a red smear of paint near the waterline of the iceberg, indicating that something had recently collided with the iceberg.
Sometimes icebergs will "roll over" if they are unstable. Gravity always pulls the iceberg, so if it rolls enough in the ocean, it may be pulled enough to roll completely over. Here is a video of an iceberg rolling over in Greenland:
