Grades K–2 · Earth & Space
How can rain disappear into the ground?
When rain lands on a garden, some drops seem to disappear. The water has not vanished. It has moved into tiny spaces between bits of soil. A drop can travel down through connected spaces, leaving the top of the ground less wet.
Soil is not one solid block. It contains grains, small cracks and tunnels made by roots and animals. Some water stays in small spaces where plant roots can reach it. Some travels farther down. Water also spreads sideways, so its path is not always straight.
The blue drops pass between brown grains rather than through the grains themselves.
A hard paved path lets much less water through than open soil. Rain may run along its surface instead. Even soil cannot take in water without limit: when rain arrives faster than it can enter, puddles form. A puddle tells us about both the falling rain and the ground beneath it.
About this explanation
Water takes different paths in different soils; this picture shows one small patch after rain.
Starting knowledge: Follow familiar changes in water, sunlight and rocks using pictures.
Sources
- U.S. Geological Survey — How Ground Water Occurs
- U.S. Geological Survey — Groundwater recharge and discharge