The Formation of Stalactites and Stalagmites
In The Formation of Stalactites and Stalagmites, narrator Sir David Attenborough explains the fascinating process of how stalactites and stalagmites form in caves, focusing on the Bornean caves. Rainwater eats away at limestone, leading to the formation of these unique cave structures. Water loaded with dissolved limestone deposits calcite to create stalactites from the ceiling and stalagmites from the floor. This video is excerpted from BBC’s Planet Earth, a breathtaking documentary series that highlights the natural wonders of our planet.
Lesson Express
Q: What is the process by which stalactites are formed?
A: Stalactites are formed when water loaded with dissolved limestone drips from the ceiling, leaving behind small amounts of calcite, which slowly builds up over time to create these hanging formations.
Q: How do stalagmites differ from stalactites in their formation?
A: Stalagmites form on the cave floor when water seeps quickly and deposits calcite at the bottom, whereas stalactites form on the ceiling when water drips slowly.
Q: What factors contribute to the different shapes of cave formations?
A: Variations in water flow and air currents contribute to the different shapes of cave formations, as they affect how and where calcite is deposited.