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Size of Molecules Experiment

kit #121

This Lab-Aid allows students to intuitively enter the micro world by determining the size of a molecule. The experiment utilizes the principle that oil and water do not mix. Students isolate a single layer of molecules and learn how the thickness of this monolayer can be calculated when the volume of the substance and the area it covers is known. The computations employed in this kit were originally developed by Dr. Irving Langmuir to deduce the size of a molecule.


  • Deduce the order of size of a molecule
  • Intuitively step into the micro world
  • Utilize math computations

Content List in Size of Molecules Experiment is as follows:

Quantity Description
1 Teacher’s Guide with MSDS
50 Student Worksheets and Guides
12 Activity plates
12 Metric rulers
1 Bottle of Hydrochloric acid, dilute
1 Bottle of Talcum powder
2 Drop control bottles of Arachidic Acid
2 Drop control bottles of Lauric Acid
2 Drop control bottles of Palmitic Acid
2 Drop control bottles of Sorbic Acid
2 Drop control bottles of Stertic Acid
Number of students
Number of groups
Maximum 12 groups per period

To complete this kit requires one ~50-minute class period.

Title Item # Price Quantity
Size of Molecules Experiment 121 $123.55
Size of Molecules Experiment REFRESH-A-KIT 121-RC $72.05