Density In A Wave Machine

Deloris Braham                 Horace Mann
1052 East 80th St.             8050 S. Chappel
Chicago IL 60619               Chicago IL 60617
                               (312) 535-6640

Objectives:

This can be adapted for any grade.
  1. Understand the concept of density.
  2. Understand the concept of density as it relates to liquid.
  3. To demonstrate that a less dense liquid will float on a denser liquid.
  4. To demonstrate that different types of liquids have different densities.
  5. Develop the skills of observing and predicting.

Materials Needed:
  
  - 2 bottles or jar with tight fitting lid
  - water or alcohol
  - cooking oil, mineral oil, or paint thinner
  - food coloring
  - metallic paint (gold or silver) optional
  - funnel

Safety Tips:

  Petroleum based solvents work best for this activity.  Some are flammable
  or irritants.  However, with small children cooking oil and mineral oil
  should be used instead of paint thinner.  Water can be substituted for the 
  alcohol.  If you use metallic paint Please Use Glass Bottles.  The thinner
  and paint might react with or soften the plastic.

Procedure:

  Fill the bottle half full with water or alcohol.  Add a few drops of food 
  coloring and a few drops of silver or gold paint.  Metallic paints contain
  small flecks of metal which enhance the effect of the wave motion.  Pour
  any of the oils into the bottle until it is full.  Attach lid to the bottle.
  Shake the bottle.  The water, alcohol, and oils mix but soon separate.  The
  color will be on top.  To get coloring on bottom use bottle #2 and reverse
  the procedure.
  Tilt the bottle on its side.  Slowly tip the bottle back and forth.  The 
  motion will generate interesting wave patterns.

Strategy:

  Explain to the students how they will predict and experiment with
  density.

  Using the following words:
     density   solution
     liquids   solute
     mass      solvent
     matter    suspension
     mixture   volume
  
  Make words from vocabulary words.
  
  Find a word from puzzle.
  
  Arrange vocabulary words in alphabetical order.
  
  Unscramble words and match with definition.
  
  Play Jeopardy.

  Direct students to observe the liquids.

  Make a list of observations of the liquids.

  Weigh each liquid and make a prediction on the ranking of the liquids from 
  least dense to most dense.  Record prediction and actual weight.  Record the 
  actual order of the liquids by density and compare the difference between the 
  prediction and the actual results. 

  Teacher and students will discuss the following questions:
  
      What happens when you stop shaking the wave machine?

      Why does the oil float on the water and alcohol?

      In each container mix food coloring with water, alcohol, and water.  
        What happens?

      Why is there separation between water, oil, and alcohol?

      What kinds of things dissolve in water?

      What will not dissolve in water?  Why?

Performance Assessment:

  Discussion and questions raised during activities.  Successful completion
  of the wave machine.

Conclusion:

  Density is one of the basic properties of matter.  Density is mass/volume.

Reference:

1994 Jake's Attic Productions