In this activity learners use an EarthBox to model how groundwater flows through soil. A more sophisticated middle school version of the activity is also available. The EarthBox setup instructions are modified to only use potting mix, and not fertilizer or seeds. Every day learners observe whether the soil is wet or dry to the touch, then add a measured amount of water. When the soil is finally moist, there is a reading explaining how water moves from wet areas to dry areas through capillary action, both in soil and in plants. The soil should take a few days to get wet, which is the end of the experiment.