`Density - An IntroductionTherese R. Tobecksen           St. Andrew the Apostle                               331-155th Place                               Calumet City IL 60409                               (708) 862-4143Objectives:1.  The student will review the concept of heavy vs. light.2.  The student will review the concept of sink and float.3.  The student will conclude that solid objects of the same size and shape can     have different weights and therefore different densities.4.  The student will conclude that liquids and gases can also have different     densities.Materials Needed:Clear flat pan of water, a variety of objects to investigate the sink and float concept, a concrete canoe (or any object that students would predict would not float but will), a pan balance, a variety of objects to test the concept of heavy vs. light, three like size cubes of aluminum, brass, and steel for each group, corn syrup, corn oil, one jar or beaker per group, three small plastic cups or containers per group, large jar for "density jar", petri dishes, ball bearings, glycerine, small scrap of wood, plastic bingo chip, rubber stopper, steel washer, two one liter plastic bottles, mineral oil, paint thinner, alcohol, helium balloon Strategy: 1. Ask students to predict if concrete canoe will float.  Test predictions. 2. Have students test various random objects on a balance to determine heavier     and lighter objects. 3. Have students test objects to see which sink or float. 4. Show equal sized metal cubes of aluminum, brass, and steel.  Have students     make some predictions about their weights. 5. Let students discover that the metal cubes are not the same weights. 6. Show two petri dishes, one packed with ball bearings and the second one     loosely packed.  Place on overhead and introduce the word "density". 7. Show bottles of corn oil, corn syrup, and water and invite comments about     texture, and thickness of fluids. 8. In small groups, allow students to pour small pre-measured quantities of    corn syrup, water, and corn oil to see that each liquid forms a separate    layer. 9. Show first wave bottle containing mineral oil and blue colored water.  Have     students conclude that the blue water is more dense.10. Show second wave bottle containing paint thinner and alcohol.  Have students     decide which liquid is more dense.11. Make a density jar.  Into a jar pour corn syrup, glycerine, water, and corn     oil.  See at what level steel, a rubber stopper, a plastic bingo chip, and     a wood chip will float. 12. Take out a helium balloon and lead students to conclude that the balloon     floats because the helium in the balloon has a lower density that the air     in the room.Performance Assessment:Show students a glass of ice water.  Ask them if they think that the ice or the water has a greater density. `