Island Explorers Curriculum Home


Unit 1

Lesson Plan 1

Lesson Plan 2

Lesson Plan 3

Lesson Plan 4

Lesson Plan 5

Concepts/Objectives | Vocabulary/Background | Activity | Extension


Lesson Plan 5



What happens when ocean water, brackish water, and river water contact one another?


  • The density difference between two volumes of water can prevent them from easily mixing. Water containing the most dissolved salt tends to form the bottom layer while the less dense water will remain on top of the more dense water.


  • observation
  • prediction
  • analysis


  • Students will be able to predict results and analyze what happens when water of differing densities come into contact.


  • One 55 minute class period

For the preparation of the colored solutions:

  1. 150 ml of pickling salt (pure NaCl)
  2. 100 ml graduated cylinder
  3. 500 ml graduated cylinder
  4. 600 ml beakers (or jars that will hold more than 500 ml of liquid)
  5. food coloring (three colors: blue, red, green)
  6. stirring rod (or spoon)
  7. marker for labeling beakers
  8. tap water (about 2 liters)
  9. towels or rags for cleanup

For each group:

  1. Cafeteria tray
  2. Slice of clay 3 cm thick
  3. Clear plastic straw (about 10 cm long)
  4. Three 250 ml clear plastic cups containing 25 ml each of the colored solutions
  5. 250 ml clear plastic cup (waste container for used solutions)
  6. Three medicine droppers or plastic pipettes
  7. One or two sheets of white paper
  8. Towels or rags for cleanup
  9. Data sheet


Concepts/Objectives | Vocabulary/Background | Activity | Extension