Begin to pick up three rocks and place them one by one very carefully in the pot. When all the rocks are in the jar, ask the students:

          - Is it full?

          Grab some gravel stones and place them into the pot. Ask them:

          - Is it full now?

          Take a portion of sand and let it trickle with a gentle sighing sound into the pot where it will settle around the rocks. Turn to the adolescents and ask:

          - What about now? Is it full?

          Take a jug of water and pour it carefully.