The purpose of this activity is to explore the way water moves through a porous, soluble substance and to observe the development of pits and channels as the substance dissolves in water. Students learn what karst is and how it is formed. Educational levels: Intermediate elementary, Primary elementary

Barb Mieras

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Digital Library for Earth System Education

Sugar Cube Karst 
 
Submitted by:  Dr. Barb Mieras, Geological Society of America 
bmieras@geosociety.org 
 
Grade Level:  K- 3 
 
Subject(s):  Science/Geology 
 
Duration: 1 day  
 
Description: Sinkholes, caves, and underground drainages, sometimes 
along with steep-sided pinnacles, are typical of the karst topography that 
forms in soluble rocklayers like limestone.  In many part of the country, 
rivers or streams “disappear” into sinks, only to reappear again in springs 
downstream.  Here’s a very simple (and fairly simplistic) model of karst 
formations for younger kids. 
  
Goal: The purpose of this activity is to explore the way water moves through 
a porous, soluble substance and to observe the development of pits and 
channels as the substance dissolves in water. 
 
Objective(s):  Student will learn: 
 
1. what is karst? 
2. how is karst formed. 
3. what are pits and channels? 
 
Teacher Background:  
Karst is a type of topography that is formed over limestone, dolomite or 
gypsum by dissolution of the material, and is characterized by sinkholes, 
caves, karst towers, and underground drainage.  The karst topography 
usually forms by the flow of groundwater though areas of these soluble 
rocks.  This activity will illustrate the dissolution 
 
 
 
Materials 
(For each child) 
 
ü A pile of sugar cubes (at least half a dozen) 
ü An eyedropper (thin straw will work in a pinch, so to speak) 
ü A small container of colored water (blue works well); you may wish to 
use sugar water to slow the dissolution process, but that does make 
the activity stickier  
ü A tray or other easily cleaned surface to work on 
 
 
Procedure 
 
Teacher note: Depending on what you wish to accomplish, this particular 
activity can require some pre-activity discussion of goals and expectations 
with the kids -  otherwise you may end up with thirty little piles of blue 
sugar water on thirty little desks fifteen seconds into the activity. 
 
1. Stack the sugar cubes on the tray. 
2. Put a tiny bit of colored water on top of one of the cubes. 
3. Observe where the water moves the cube and how the shapes of the 
cube change. 
4. Add water at a crack between two cubes, a tiny bit at a time. 
5. Observe where the water moves through the cubes and how the 
shapes of the cubes change. 
6. Repeat steps 2 through 5 until you make a hole clear through or the 
sugar cubes collapse. 
 
There are a zillion variations to this activity.  You might want students to 
draw and/or take notes on their observations at each step.  You may want to 
challenge students to form specific “karst” features (sinkholes, towers, 
caves, etc.)  For more advanced students, you might want to add 
impermeable layers of clay (or another material) between some cubes or 
layers.  You could have them glue together cubes into larger structures or 
shapes.  The glue will stay behind in the shape they made.  You might wish to 
assign different stacking and/or soaking patterns to different students or 
groups: 
 
 
 
 
 
 
  
 
A couple of the many possible topics for follow-up discussion include:   
 
1. A comparison of students’ results (how do different stacking patterns 
affect the results? How do different “watering” sites affect 
dissolution?) 
2. Links between the model and the real world (how do fractures in rock 
layers affect the formation of caves and other dissolution features?  
how are real rock layers different from the sugar cubes in the model?  
Where does the water that travels through rock layers come from?  
how is it different from the water in our model?)  
 
 
 
Edited by Glenda Robinson and Christine McLelland, Subaru Distinguished 
Earth Science Educators, Geological Society of America, Boulder, CO 
Subaruteacher@geosociety.org 


Sugar Cube Karst

http://www.geosociety.org/educate/LessonPlans/SugarCube_Karst.pdf

Sugar Cube Karst

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