Early Cave Development...Passageways
This classroom activity will give students a hands-on experience creating their own cave. Individuals should come away with an understanding of the relationship between water and soluble rock.
- sugar cubes
- modeling clay
- transparent glass or plastic dish
- tooth picks
Divide students into teams of 3 or 4. Their task is to recreate a hill in a karst terrain, according to the directions below:
Constructing the hillside:
Have each team stack sugar cubes 6 wide, 6 deep, and 6 high to represent the limestone or dolomite bedrock. One side should be placed against the side of their container.
Next green modeling clay should be rolled out flat. This will represent grass on the hills outer surface. Cover the bedrock with the modeling clay. The side that is against the glass container should be left uncovered to view the experiment. Before proceeding, all edges where the clay meets the container should be pressed down and sealed tightly.
Additional clay can be used to decorate with surface features such as trees and houses.
Using a tooth pick, teams should create a hole by piercing the modeling clay gently, preferably near the exposed viewing side. Also using the tooth pick teams should create a second opening in the same fashion. This one should be located near the base of the "hill".
Now each team can slowly pour water onto their hilltop in small increments. The water will filter down through the hole at the top. The sugar will slowly erode and come out of the "spring" opening at the bottom.
Each time water enters the hilltop a little more bedrock is eroded and will leave behind passageways. As more and more water is added, the bedrock will erode to a point that the surface collapses forming a sinkhole.
Follow up with a discussion about the life of a cave. Starting as small passageways filled with water emptying at a spring and ending at a natural bridge or deep valley.