Peter.D.Riley

International bestselling award-winning author Facebook Twitter

Taking science education across the world

Our future depends on exploring all the frontiers of science, on innovative technologies based on these explorations and on the development of scientific literacy in all peoples through science education.

Stalagmites and Stalactites in The Postojna Cave in Slovenia

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

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

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.

Postojna Cave

“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.

Postojna Cave

A stalagmite formed from limestone deposited over thousands of years

Science Book Alert!

Ways into scienceYou 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!



My Books

Follow the links below to find out more about my books and book series, as well as downloadable resources for teachers and parents using my books.

Books for Primary Schools
Books for Secondary Schools

Books and Resources for Teachers

Contact Me

I can be contacted in the following ways. If you have a picture for the Natural World Photo Gallery or the Science Exhibition Gallery, please send it by email.