Very Large Ice Cubes
Satellites track them, ships avoid them (except for the unfortunate Titanic), scientists study them. They are intriguing and dangerous. What do we really know about these things called icebergs?
Amazing But True
- Icebergs form on land (glaciers) and then break off into the water as the glacier moves toward the shore. When they hit the water, the icebergs will partially submerge. The amount of ice seen above the water surface may only be one-sixth to one-ninth of the total material contained in that iceberg.
- Icebergs float because they are composed of fresh water. This water is less dense than sea water (which contains large amounts of dissolved minerals). In addition, the ice itself is less dense that the liquid water in which it floats. When liquid water freezes, the crystal structure of the ice changes and becomes less compact.
- Since icebergs are composed of fresh water formed as the glacier moves toward the sea, there have been many proposals for using this water supply for drinking, agriculture, and other applications where fresh water is needed. Currently, there are no technologically feasible ways to bring the iceberg safely and intact to an area that needs the fresh water.
- Watch a video about icebergs at the link below: https://www.youtube.com/watch?v=ewHIo2ekU4g
Use the links below to learn more about icebergs. Then answer the following questions.
- What is the smallest piece of ice that would be considered an iceberg?
- How do icebergs influence ocean life?
- At the link below, explore problems in moving icebergs to obtain fresh water. Then answer the questions on that page. http://oceanexplorer.noaa.gov/edu/learning/player/lesson12/l12la1.html
- Do icebergs make noise?