The Properties of Water
Grade Level		Prospective and Practicing K-8 Teachers; may be adapted for use in elementary classes
Time		Exercises 1-4 take approximately 30 minutes.
Objectives			Once you have completed this knowledge mapping exercise, you should be able to:
		1.	Organize ideas into categories of similar types.
		2.	Classify ideas into hierarchies of larger and smaller ideas.
		3.	Develop a better understanding of some key relationships used in biology.
Background Information			Circle diagrams provide one way of graphically organizing ideas to illustrate their inclusivity. Completing the exercises below will test your knowledge about important molecules of life, including water and oils.
Exercise 1		Organizing Inclusive Ideas
To Do		Insert the terms below into the appropriate circle in Figure 1, below. A term may be used more than once. adhesion cohesion hydrogen bonding capillary action density surface tension
		Figure 1. Some Characteristics of Water
Exercise 2		Classifying Ideas
To Do		Place each of the following ideas in the appropriate circle in Figure 2, below. Each idea may be used more than once. adhesive dissolving mixing boiling gaseous separated cohesive liquid separating dissolved mixed solid
		Figure 2. Distinguishing Among Characteristics, States and Processes
Exercise 3		Categories Figure 3, below, illustrates that water is a category of things that includes salt water, fresh water, distilled water, and colored water, among others. Colored water contains both water and dye, so might be shown as overlapping with both concepts.
		Figure 3. Many Kinds of Water
To Do			Organize each of the following ideas into one of the six circles in Figure 4, below. An idea may be used more than once. water oil detergent polar substance non-polar substance amphipathic molecule
		Figure 4. Bigger and Smaller Ideas
Exercise 4		Water/Oil Interfaces in Cells Water is the stuff of life. Many different kinds of molecules dissolve in water. Many reactions occur in water solutions.
Powerful Idea		The water - oil interface provides the basis for spontaneous cell formation. Because oils avoid mixing with water, amphipathic phospholipid molecules spontaneously form a phospholipid bilayer such that the outer surfaces consist of polar heads (interacting with the watery environment inside and outside the cell) and the center of the bilayer consists of non-polar fatty acids (Figure 5).
		Figure 5. Phospholipid Bilayer in cell membranes The phospholipid bilayer forms a membrane around the cell. If phospholipids and water are mixed and shaken, micelles (empty cells) will spontaneously form. Molecules in the body seek one of these layers.
To Do		Put the molecules below into the environment (Figure 6) where each is most likely to be found. Figure 6. Molecules and Their Likely Environments
		polar amino acid molecule from eating hamburger a fatty acid from the same hamburger vitamin E (a non-polar molecule) from the veggies vitamin A (a polar molecule) from the veggies testosterone (a non-polar steroid hormone) from the testes insulin (a polar protein hormone) from the pancreas an amphipathic transport protein