Silly Putty

Name of Activity

Silly Putty

Author

STOMP

Keywords

silly putty, chemical engineering, reaction, ratio, properties

Subject

Miscellaneous

Grade Level

5

Time

1 Hour Total

Brief Description

Students will explore the classic glue and starch reaction to create their own silly putty. They will then test it’s physical and chemical properties.

Lesson Objectives:

-Teach the importance of ratios in a reaction

-Teach the difference between physical and chemical properties

-Explore how the above two bullets are important to a chemical engineer

-focus on the observation step in the engineering design process.

Materials Needed:

-Plenty of glue (6+ bottles of Elmer)

-one large bottle of liquid starch.

-plastic baggies to place silly putty in

-pencils and pens

-plastic cups

-Popsicle sticks

-food coloring

Preparation and Set Up:

-prepare cups of starch for each student

-pass out a cup to each student and a bottle of glue for each pair

-before hand explain the 2:1 ratio of glue to starch.

Knowledge Background

-Be aware of the ratio of glue to starch (two parts white glue to one part starch). -Know a fun fact that silly putty was accidentally created during WWII -Know the difference between chemical properties to physical properties

Procedure

  1. Introduce to the class what silly putty is or remind them
  2. Ask them the different properties of silly putty (color, texture, stretchy etc).
  3. Write on the board each of their responses into two categories: physical and chemical (Physical- elastic property of silly putty; Chemical- color).
  4. Explain the 2:1 ratio of glue to starch (draw pictures if necessary)
  5. Hand out cups of starch and glue and have students mix in the glue.  Add food coloring too if available for customization.
  6. Go around and make sure the ratio is being implemented.  Doesn’t have to be perfect.
  7. Place silly putty in baggies.
  8. Once Silly putty is ready take them out and have students compare with their partner.  The ratio effects the silly putty’s properties!  Not one silly putty will be exactly the same as another student’s
  9. Have them record the silly putty’s physical properties (What happens when you stretch fast vs Slow).
  10. Have them record the silly putty’s chemical properties by having them draw once with pencil and once with pen and sticking the putty onto the paper to see how the drawing sticks.  Record which one comes out better.
  11. Put back in baggies to take home!

Extensions:

-use different ratio and compare multiple silly putties’ properties

Modifications:

Make different types of silly putty using different recipes and see which recipes work best.

Online Reference(s)

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