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[AZ Extension Water Quality ] Youth Activities ] Glossary ]
Activity G-1: Mini-Groundwater Models
This youth activity is one in a series of two activities that can be used to introduce groundwater concepts.  It is a good introductory activity and can be adapted for all grades.

To demonstrate the concepts of groundwater, aquifer, infiltration, leaching, percolation, water table, and soil profile.
(This information was taken from GROUNDWATER: A VITAL RESOURCE Student Activities by the Cedar Creek Learning Center in cooperation with the Tennessee Valley Authority. 1986.)
Groundwater is defined as the water that seeps or percolates into the soil and is stored in an aquifer (water bearing material like gravel) where it can be pumped out for use.

Groundwater accumulates chiefly from rain that filters through the soil (also known as percolation, and leaching).  It also forms from water that seeps into the ground from lakes and ponds.  The water settles into the pores an cracks of underground rocks and into the spaces between grains of sand and pieces of gravel.  A layer or bed of such porous materials that yields useful amounts of groundwater is called an aquifer.  Wells are drilled down to an aquifer to draw groundwater to the surface.

The surface of groundwater, called the water table, drops when more water is withdrawn than can be replaced naturally.  In some areas that have large populations or little rainfall, the groundwater supply may have to recharged artificially.  However, many regions of the world are using up the groundwater faster than aquifers are being recharged.

Pollution of groundwater is a serious problem.  Pollutants that seep into the ground can come from contaminated surface water, leaks from sewer pipes and septic tanks, and gasoline and chemical spills.  Groundwater may also be polluted by chemical fertilizers and buried radioactive wastes.

for each student or group of students:
* clear plastic cups, about 10 oz in size

* paper coffee filters, cut into 2 in. diameter rounds

* 1/4" clear tubing-cut to 6" lengths (I use vinyl tubing, can use aquarium tubing

* 10 cc capacity syringes

* duct tape (you need a very sticky and strong tape)

* 1/3 c each of gravel, sand, topsoil

* 1 squirt bottle, mister, etc. filled with water

* food coloring, optional

  1. Take one length of clear tubing and tape to inside of cup so that the end of the tube rests on the bottom of the cup.  The cup represents a "cut-out" of your backyard and the tubing is the "well."

  2. Add a layer of gravel to the bottom of the cup.  This represents the water holding material which makes up the aquifer.

  3. Place a paper filter on top of the gravel.  This is a "semi-permeable membrane" (i.e., water passes through but the soil and sand above it do not).  Many soils act as semi-permeable membranes.

  4. Add layers of sand and soil.  This is the soil profile of your backyard!

  5. Spray water on top of soil - this simulates rain.

  6. Watch the water percolate through the soil and collect in the gravel (aquifer).  This is a good way to demonstrate percolation.

  7. Use a syringe as the pump and withdraw water from the "aquifer."  (The syringe acts as a vacuum pump.)

  8. Optional:  add food coloring to the soil top near the well to act as pollution.  See food coloring in withdrawn water.

  1. Add all of one soil and compare infiltration rates (time it takes for the water on top of the soil to get to the gravel or cut holes in bottom of cup).

  2. Add food coloring to top of soil and ask students how much water will need to be added to the system before all the coloring is gone.  Is the food coloring still there?  Let the water evaporate to see if pigment remains.

  3. Find out what a typical soil profile is in your area and simulate that profile in the cup.  Measure how long it takes water to reach the "aquifer."  Draw conclusions of how long it would take for a pollutant to pollute your community's aquifer.

  4. What pollutants from the activities in your community might the food coloring represent?  Discuss point and nonpoint source pollution.
This activity was adapted by Dr. Kitt Farrell-Poe from the Invitational Professional Development Workshop: Water Activities Teaching Environmental Responsibility. February 28-March 4, 1990. Camp Ocala, 4-H Center, Altoona, FL.

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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture, The University of Arizona. The University of Arizona College of Agriculture is an Equal Opportunity employer, authorized to provide research, educational information, and other services only to individuals and institutions that function without regard to sex, race, religion, color, national origin, age, Viet Nam Era Veteran's status, or disability.

For problems or questions regarding this web contact Dr. Kitt Farrell-Poe.
This document was last modified: 31-Aug-2005 .