Classroom Activities

Constructing the hillside:

1. 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.

2. 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.

3.Additional clay can be used to decorate with surface features such as trees and houses.

4. 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.

Materials needed:

charcoal crushed to a fine powder, multiple colors of dirt (black, red clay, etc.), lard, crushed berries of different colors, bowls to mix paints, paint brushes, stones with a relatively flat surface, (poured concrete pavers will also work).

Students can be divided into small groups, however this project works best with each individual creating their own prehistoric work of art. It is best to mix up paints ahead of time and then let your students create smaller quantities to appreciate the process.

Creating the Paints

1. To create blacks, reds, and browns, mix one of the materials -charcoal, clay, or dirt - with the lard. It will take a few tries to get the consistency right. If it is too dry, add more lard; if it is too wet, add more material.

2. Reds and purples can be made by crushing raspberries or blackberries and diluting slightly with water. If you prefer, powdered tempera paints can be used to represent different things in the environment; yellow for sulfur, brown for dirt, orange for clay, red and purple for berries, etc.

Materials needed:

four two-liter plastic soda bottles, tape and scissors, plastic tube or long straw, stones, sand, aquarium gravel, brightly colored powdered drink mix, aluminum foil, 1/4 cup measuring cups, water.

Divide students into teams of 3 or 4. Their task is to recreate a watershed found in both a karst and non-karst area, according to the directions below:

Constructing the Karst Watershed

Cut about 2.25 inches from the bottom of the first bottle.

On the second bottle cut 2.5 inches from the top. Set aside the top for later use. Pour 1.75 inches of water in the bottom.
Place the first bottle upside down into the second bottle.

Insert the plastic tube through bottle #1. (To keep it steady within the cut-off top, you may need to pack the tube with aluminum foil.)

Pack stones into the inverted bottle around the tube with the stone level higher at the edges and lower in the center.

Lay sand on top of the stones following the curve up the sides of the bottle.

Lay the cut-off top portion of bottle #2 upside down on the sand with the plastic tube extending through the cap screw portion. Arrange the tube until it extends no higher than the cap screw portion of the cut bottle and tape it into position.

Constructing the Non-karst Watershed

Follow the first 3 steps for the model above.

Pack stones into the inverted bottle higher at the edges and lower in the center.

Add a layer of aquarium gravel (slightly packed) higher at the edges and lower in the center. (Soil layers tend to be thinner in karst watersheds than in non-karst watersheds. The gravel layer gives this model thicker "soil.")

Add a layer of sand on top of the gravel following the curve up the sides of the bottle. On the model, have students identify the ground water, rock, soil, and sinkhole. Ask students to predict what will happen when it rains.

Now, ask students to compare their watersheds.

Once groups have completed the two watersheds, establish the different features represented in their models. They should recognize bedrock, soil, and sinkhole. After geographical features have been established ask students to predict what would happen when it rained.

Next have each group simulate "rain" by pouring about 1/4 cup of water over each of their models. Once it has rained on each group's karst and non-karst watersheds, discuss what students saw in their models. After everyone understands the relationship between the surface and sub-surface, have students brainstorm what other substances can get into the groundwater from the surface.

To represent pollutants, sprinkle the drink mix across the top layer of each model. Brainstorm what will happen when it rains next. After all input, students should simulate the next rainstorm. Once the rain has ended ask students what they saw in each of their models. Leading questions such as "Which watershed had a polluted water table first?" should be enough to wrap everything together for individuals.

Follow up with a discussion about how to prevent groundwater pollution. Topics like better education of the public and groundwater monitoring should be part of the discussion.