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Growing With Groundwater

Objective
Identify the 4 components (water, air, food/nuitrients/soil, and sunlight) necessary for providing and sustaining life. Identify how groundwater fits into the water cycle. Build a miniature terrarium containing all 4 components.

Materials Needed

• Clear glass/plastic jar with lid (good idea: recycle an empty mayonnaise jar. If you don't have a jar, try a clear plastic drinking cup fashioned with a lid made from plastic cling wrap and a rubber band)
• Gravel
• Potting soil
• Spray bottle filled with water
• Plant seeds (good idea: choose herb seeds, they grow fast and are edible) or plant seedlings
• Large spoon or trowel

Vocabulary

groundwater, aquifer, infiltration, recharge, evaporation, condensation, precipitation (view Groundwater Glossary)

Procedure

1. Ask yourself what do plants and animals require in order to grow? Hint: There are four. Answer: Water, sunlight, food (ie nutrients from the soil), and air. In this activity, we will build a model that contains all these components necessary to make the seeds grow.
2. Fill the bottom of your jar with 1 to 2 inches of gravel. Add about 4 inches of potting soil on top of the gravel.
3. Plant your seeds as instructed (refer to packaging instructions from manufacturer if necessary).
4. Water generously with spray bottle. Watch as the water trickles down through the soil and into the gravel layer. This water you see below the surface of the soil is called groundwater and will be used by the seeds to help them grow.
5. Secure lid and place in a sunny window. Over the next few days, watch as the sides of the jar become foggy. This is condensation, or clouds. Heat from the warm sun caused water to evaporate from the soil (become a vapor) then cool and condense (become a liquid) on the walls of the jar. As the water on the walls of the jar becomes heavy, it falls to the ground as precipitation (or rain) and waters the seeds by infiltrating or recharging (sinking into the soil) and becoming groundwater again.

Note: If your jar becomes too foggy, simply crack the lid for a day or two in order to prevent the growth of mold. If you leave the lid off too long, your soil may dry out and require an additional squirt from your spray bottle.

Conclusion
Water molecules are constantly on the move in what is called the water cycle (or hydrologic cycle). Heat from the sun causes the water to evaporate and become a vapor. As the water vapor cools, it condenses, forming tiny droplets which gather to form clouds. As the droplets get larger, they become heavier causing them to fall to the ground as precipitation (like rain, sleet, or snow). Some of this precipitation joins lakes and streams (called surface water), and some of it soaks into the ground where it becomes groundwater. The process of water soaking into the ground is called infiltration, or recharge. Plants and animals alike require four simple things to keep us healthy and allow us to grow. They are water, food, air and sunlight. If one of these items is missing, we become sick. If one of these items is polluted or dirty, we become sick. Can you think of something that might make water unsafe to drink, food unsafe to eat, or air unsafe to breath?

Activity Source
The Groundwater Foundation