Note: while a stalactite and a stalagmite are formed from the same drops of water, the nature of their growth means that a stalactite may possibly grow in length faster than a stalagmite will grow in height. However, the stalagmite will most likely be wider than the stalactite. There are two easy ways to help your students remember the difference between a stalactite and stalagmite:
- Stalactite is spelled with a C for ceiling
Stalagmite is spelled with a G for ground
- A stalactite holds "tite" to the ceiling
A stalagmite "mite" reach the ceiling someday
Column - Usually a stalagmite is directly below a stalactite. Over much time they may finally meet. As calcite continues to run down the length of the stalactite, it now continues to run down the connected stalagmite smoothing the connection point. Some columns have been together for so long it is hard to tell where the two formations first joined.
Flowstone - Similar to the formation of a stalagmite. However, the area receiving the deposit has a slope to it, so the water runs down the slope in a wide spread. A flowstone can cover a large area.
Drapery/ bacon strip - When a water drop emerges on a vertical wall, gravity drags it down the side of the wall depositing calcite in a line. Each additional deposit builds up this fine line until it looks like hanging material. Draperies with red hues, caused by iron and other minerals in the calcite solution, look like bacon strips.
Rimstone Dam - (also known as Gours in Europe) Depressions in the cave floor may collect saturated water. The calcium in the solution will deposit around the edge of the pool. Eventually the deposits build up so high that more and more water can be held. The calcite deposits act as a dam.
Cave Pearl - (also known as Oolites) If a pebble is in a rimstone pool, the saturated water will coat it. As water drops continue to fall in the pool, they cause ripples which gently roll the pebble, giving it a smooth coating.
Experiments & Activities
Grades K - 4 "Create a Cavern"
Build a cavern bulletin board or diorama. Students can cut and paste, draw pictures, or create three dimensional artwork.
Students may also create a classroom cavern. (This is done by draping three sides of a table with a dark cloth or using a large box) Suggestions include: narrow tubes (paper towel holders) for soda straws, cones for stalactites and stalagmites, crumpled balls of paper to "build" flowstone. Glue or tape the formations into the display.
