Saturation

• From where does ground water come?
  
  
• What causes streams and rivers?

Do this experiment with different types of soils. Try sandy soil, soil that has plants, etc. Make sure the soils you use are all dried the same amount before beginning the experiment.

• Put a cone of filter paper in a funnel. Place 100 ml (about 1/2 cup) of dry soil in the funnel and tamp the soil gently. Pour 5 ml (about one teaspoon) of water onto the soil every 30 seconds until water appears at the bottom of the funnel. Repeat the experiment with the other soils and new filter cones.

Through which types of soil does the water "percolate" slowest? Why?

Soil will hold most of the water added to it until it is "saturated." The soil will release water at the same it is added after saturation is reached. Use the concept of saturation to describe how streams are formed.

On a sheet of paper answer these questions with a partner.

• How did you know the soil was saturated?
  
  
• What happened to the water once the soil is saturated?
  
  
• Where does water go after it runs to a stream? (List at least 2 possibilities.)