Beacon Lesson Plan Library

Crazy Putty Ratio

Georgia White


Students mix various ratios of liquid starch and glue to make craxy Putty (their variation of Silly Putty) using knowledge of measurements and ratios. They chart their ratios, make observations, and write summary of activity.


The student writes notes, comments, and observations that reflect comprehension of fifth-grade or higher level content and experiences from a variety of media.

The student explains and predicts which outcomes are most likely to occur and expresses the probabilities as frations.

The student knows that different materials can be physically combined to produce different substances.


-Container of Silly Putty
-Small Dixie cups to put starch in (1 for each group)
-Liquid starch (Small amount in cup for each group)
-Elmer’s school glue (Small bottle for each group)
-Food Color
-Pop sickle sticks to stir mixture (1 for each group)
-Container to mix in (One per group)
-Metric measuring cups (One per group)
-Water and paper towels for clean up
-Plastic sandwich bags to put Crazy Putty in (Enough for each student and each group)
-Index card for each group with measuring instructions written on them
-Crazy Putty Data Worksheet and pencil (1 per student)--see attachment
-Poster board and markers to make Crazy Putty Data--see attachment
-Paper and pencil for each child to write summary of activity


1. Gather materials for activity.
2. Write formula on index card for each group. (See attached file)
3. Make class Crazy Putty Data chart. See attachment
4. Copy of Crazy Putty Data Worksheet for each student. (See attached file)


1. Prior knowledge needed for this lesson: Establishing ratios, mixtures, solutions, and understanding of the term tensile strength.

2. Set the Stage--Pull out Silly Putty and play with it. Bounce it. Stretch it until it breaks. Pull apart quickly to tear apart. Ask the students the following questions: What do you suppose can be mixed together to make something similar to Silly Putty? List responses. Discuss probable ratios that would yield a product comparable to Silly Putty.

3. Divide students into groups.

4. When students are ready to measure and mix, give each group an index card with formula written on it. (See attachment)

5. Have groups measure and mix formulas, add food coloring of their choice, and complete Crazy Putty Data Worksheet, place Crazy Putty in bag, and label bag.

6. Log information on class chart.

7. As a class, discuss each result and determine best mixture.

8. Play with results. Stretch. See which one stretches the most before it breaks and has the most tensile strength.

9. Discuss real life applications noting expansion and tensile strengths are needed for bridges, roads.

10. Have each student write a summary of activity using information on their worksheet, and cite uses/needs for tensile strengths.

11. Let each child make his own batch of Crazy Putty mixing the correct ratio of starch to glue take home.


1. Observe students’ measurements and check to make sure they are correct.
2. Use the Crazy Putty Data Worksheet to check for correct data and observations.
3. The math journal entry should be written from worksheet, and should include measurements of substances, show ratios, describe resulting products, and cite observations.
4. The attached rubric can be used to assess the math journal entries. (See attachment)
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