Tez has sent in some pictures of his trip into the Postojna Cave in Slovenia. The cave has formed in limestone rocks as the rainwater has seeped through them.
Postojna Cave, Slovenia
The rainwater dissolves the rock and leaves a space which forms the cave. You can see Class 3 making caves in a similar way in their sugar lump mountains in the blog of the 12 March.
The bridge was built by prisoners of war during WW1
When more water seeps through the rock, it forms drops on the cave roof. These eventually fall to the floor and as they do so a small piece of dissolved rock reforms on the roof. In time as more drops fall from the same place a column of limestone forms called a stalactite. It hangs from the roof.
“Spaghetti” stalactites hanging from the ceiling
At the place where the drops hit the floor more dissolved limestone forms. In time they form a column of rock called a stalagmite.
A stalagmite formed from limestone deposited over thousands of years
Science Book Alert!
You can find out more about stalactites and stalagmites form In the Real Scientist Stuff pages 10 and 11 and you can discover how to grow your own stalactites and stalagmites too!
