Boys holding mud for crafts for kids

Science Experiment: Create Your Own Sugar Cube Cave

Create Your Own Sugar Cube Cave

Adapted from Exploring Caves and Karst – A Cave and Karst Curriculum

(American Cave Conservation Association, Inc.)

There are two kinds of sedimentary rocks on the Blue Mounds: dolomite (a type of limestone) and chert.  Chert is harder than dolomite and is typically found on top of the dolomite. Chert forms a “cap” over the softer dolomite that slows weathering and erosion. The caves in this part of Wisconsin are formed in the dolomite layers!

You will need: modeling clay (4 oz per person or small group), Sugar Cubes (3-6 per cave), warm water, Clear bowl (cutting the top off of 2-liter bottles works well/ 1 per person or small group)

  1. Flatten the clay into a pancake.
  2. Place the sugar cubes on the clay and make certain they are all touching each other. Be sure that at least one cube touches the edge of the clay.
  3. Wrap the clay completely around the sugar cubes, forming a ball or oval shape.
  4. Expose at least one of the sugar cubes of your sugar cube cave.
  5. When the ball of clay is placed in the bowl filled with warm water, the sugar will dissolve, leaving a “limestone cave” behind. 
  6. Draw a picture that shows what your cave looks like!

The limestone (dolomite) at Cave of the Mounds has formed 400-500 million years ago when the area was covered by a warm, shallow sea.  This “Ordovician Ocean” was teeming with life: cephalopods, brachiopods, crinoids, and trilobites.  As these creatures died, their remains would sink to the bottom of the sea.  The leftover bits of animals, plants, and sediments were compacted and cemented together to form limestone. The caves in Southwestern Wisconsin were formed by flowing water that seeped through the natural cracks in the limestone.  It has taken huge amounts of water and a long time to form Cave of the Mounds!

Stalagmite at Cave of the Mounds