`Density of LiquidsPatricia Doyle                 Peck School                               3826 West 58th Street                               Chicago, Illinois 60629                               (312) 535-2450Objectives:1.  Students will discover liquids have different densities.2.  Students will learn that the temperature of water affects its density.3.  Students will develop a definition for density of liquids.Materials:For each group of 4-6 students:balance                                        cooking oil3 identical clear plastic glasses              water1/4 cup measuring cup or graduated cylinder      corn syrupstirring rod or stick                          2 one pint jarsfood coloring                                  2 small aspirin bottlespaper towels                                   lab sheets for each studentfelt tip markers or crayons                    green liquid soap and alcoholStrategy:1.  Using green liquid soap and alcohol, have the students measure 1/4 cup or     60 mL of each liquid and pour it into two separate plastic glasses. 2.  Have students identify properties of these liquids.  Do both liquids take up    the same amount of space?  Do they have the same mass (weight)?  How can we    find out?  Have the students lift and feel.  Next have them use the balance     to determine the mass of each liquid.  Record the mass on the board and the    students will notice that the soap has more mass than the alcohol. 3.  Introduce a new term density.  When one liquid has more mass than another     and takes up the same amount of space, we say it has a greater density. 4.  Next, have the students observe as you slowly pour the alcohol into the     glass with the soap.  Did the soap and alcohol mix?  Why or why not?  The     soap and alcohol take up the same amount of space but the soap has more     mass.  When we pour the alcohol into the glass of soap, the children observe     that the alcohol does not mix; it floats on top of the soap. 5.  Set up stations for groups of 4-6 students.  Using lab worksheet, each     student will determine the density of water, corn syrup and cooking oil.     Students will weigh and record the mass of 60mL of each liquid.  Next they     will add 3 drops of food coloring to the glass of water and stir.  Then they    will pour the water slowly into the glass of oil.  Does the oil and water     mix?  Which is denser?  Finally, they will carefully pour the syrup slowly     down the side of the glass containing the water and oil; set the glass flat     and observe which liquid is the densest. 6.  To demonstrate that the temperature of water will affect its density, have     the students fill a small bottle nearly full with hot colored water.      Holding their finger over the mouth of the bottle have them slowly lower the     bottle into a larger jar of cold water.  When the students slowly remove     their fingers from the bottle, they will observe that the colored hot water     floats.  Reversing the experiment and putting the cold colored water in the     small bottle and the hot water in the larger jar will show that cold water     is heavier (denser) than hot water.  As the water temperature evens, the     water mixes.  Do hot and cold water have the same density?  If not, which     is denser? Evaluation:Have the students draw pictures and label what they observed in each of theexperiments.  Extension Activity:Find some small objects, for example, marbles, plastic pieces, paper clips, styrofoam, aluminum and wood.  Have the students predict on which layer each object will float and then drop each object into the glass of layered corn syrup, water and oil.  Observe what happens. `