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Silly Semi-Solids

Tue, 2006-09-12 20:28 — tex



Grade Level:  Elementary School, 3rd-6th

Related classroom topics:  Chemical Engineering, Polymers/Plastics

Supplies Needed: 

Divide students into groups of 2-3.  Each group should receive: 

·        White glue (Elmer’s glue)

·        Water

·        Borax (in the laundry section of a grocery store)

·        Margarine tub or small mixing bowl

·        Measuring spoons

·        Small ziplock bag

Procedure: 

1.      Measure 2 Tablespoons of water and pour into mixing bowl.

2.      Measure 2 Tablespoons of white glue and pour into bowl containing water.  Stir until well mixed.

3.      Measure 2 Tablespoons of borax and mix into the same bowl.  The mixture will begin to congeal immediately.  A film will form on the surface of the water/glue solution.

4.      Use your fingers to thoroughly mix the ingredients.  A large “lump” of wet semi-solid will begin to form between your fingers.  Keep mixing ingredients until the lump feels like wet putty.  The excess fluid remaining in the bowl is safe to flush down a sink drain.

5.      Knead the putty material in your hands until it is completely smooth (5-10 minutes).

6.      Begin to experiment with the unusual properties of this substance.

7.      You can store your silly semi-solid putty in a Ziplock bag.

8.      Wash your hands after this activity.

Extensions: 

Possible questions to discuss:  What happens when you slowly stretch it?  What happens when you pull it abruptly apart?  If you roll it into a ball, does it stay in that shape?  Is this substance a solid, fluid, or something in between?  Can you imagine any useful applications for a material with these properties?

Related topics you could discuss:  Polymers, plastics, chemical engineering.  Applications of semi-solid materials.

Hints/Tips:  To expedite this process, let students create this in groups with each student having a certain task.  Split up the putty into equal sections so each student can take some home. 

Original Experiment Submitter:  Allison Edner from Washington