1. Seeping rainwater and rivers flowing underground continue to dissolve the limestone because of the carbonic acid dissolved in the water.
2. Gradually, large open areas called passages and caves are formed.
3. When the water containing the dissolved carbonic acid seeps into the roof of the cave, it begins to drip. Some of the droplets hang on the roof of the cave for a while. As they hang, some water evaporates and leaves behind a tiny deposit of calcite (calcium carbonate).
4. These deposits can build up slowly over thousands of years, hanging from the roof of the cave. They are called stalactites .
5. If water droplets fall onto the floor of the cave, they also leave behind a deposit of calcite. Over time these deposits build up on the floor and grow upwards to form stalagmites .
6. If a stalactite and stalagmite meet and join, they form what is called a pillar . Working with others
1. Looking at the photo, name the features labelled A, B and C.
2. Where is the largest stalactite in Ireland? Where is the largest stalactite in the world? Go online to find out.
A limestone cave A
C B 122
FUN FACT! Think stalactites have a
‘T’ for Top and stalagmites have a ‘G’ for Ground to remember the difference between the two.