Academy Curricular Exchange
Columbia Education Center
Science

TITLE:  ˙VISUAL MODELS OF SOLUTIONS AND CONCENTRATIONS

AUTHOR:  Don Kissinger

GRADE LEVEL/SUBJECT:  9-12,  physical science 

OVERVIEW:  It is difficult for students to understand the
concept of solutions and concentrations.  A visual model is
very helpful as an aid to learning.

PURPOSE:  The purpose of this project is to give students a
hands on model to work with which will demonstrate the 
manner in which solutions are formed.

OBJECTIVES:  Students will be able to: 
  1.  Discuss pure solutions.
  2.  Discuss dilute solutions.
  3.  Discuss concentrated solutions.
  4.  Discuss the volumetric changes which occur.
  5.  Apply use of the model to future learning.

RESOURCES/MATERIALS:  Materials needed are listed above in
the activities section.

ACTIVITIES AND PROCEDURES:  
  1.  Each lab table is provided with four 300 ml. beakers.
Each beaker contains one size and one color of glass or plastic
spheres.  The spheres range in size from l mm. to 8 mm. in
uniform increments, each size sphere having its own color.
  2.  The students are led to understand that the beakers
represent single molecules of pure substances.
  3.  The students first record the volumes of each of the
beakers and enter this information into their data tables.
  4.  The students are then told to pour the beaker of smallest
spheres into the beaker of largest spheres and mix well with a
glass stirring rod.  The new combined volume is
then recorded in the data table.  (The students note that
the smaller spheres tend to fill in the spaces between the
larger spheres, thus demonstrating the addition of a solid to a
liquid forming a solution.)
  5.  Students are encouraged to make many combinations of
different sizes and colors of spheres and to record the
volumetric changes.

TYING IT ALL TOGETHER:  In subsequent work with solutions and
concentrations, students are encouraged to refer back to the
models as an aid to understanding.  A set or two of these beakers
are left on display for student use to encourage further exploration. 

Click here to return to OFCN's Academy Curricular Exchange

Click here to return to OFCN's Academy
Click here to return to OFCN's Main Menu