And the Mystery Powders

Written and designed by David Crowther & Ryan Ross

Most teachers either have done or have heard of Oobleck. Many curriculum sources including AIMS, Scholastic, and Operation Chemistry have capitalized upon this phenomenon. However, many of these teaching situations involve a premeasured and / or prescribed situation utilizing a traditional recipe style format for learning. The following is our creative twist which takes the traditional Oobleck lesson and turns it into a discovery lesson utilizing a variety of science process skills which integrate science, math, literature, and language arts.

Objective/Outcome: The students will use process skills of investigation to determine what the ratio is of water to powder and which mystery powder forms Oobleck.

Materials:

Bartholomew and the Oobleck by Dr. Suess
4- 8 Boxes of Corn Starch
1 gallon baggie with dehydrated colored Oobleck
1 gallon Ziplock Baggie of flour
1 gallon Ziplock Baggie of baking powder
1 gallon Ziplock Baggie of powdered sugar
1 gallon Ziplock Baggie of corn starch
3 oz. Solo cups (1 per each student)
12 oz. Solo cups 2 per student.
Variety of measuring devices - can range from standard measure for younger grades to metric measure for older grades. The 3 oz. cups could be created to be a measuring device to find a ratio also.
Food coloring (optional)
Popsicle sticks for stirring (optional)
Paper towels
Water - a 5 gallon bucket should prove plenty if there is not a source in your room.

Set Up:

In advance prepare a small amount of Oobleck. About 3 oz. of corn starch to 1.5 oz. water should be enough for the demonstration. Add green food coloring for effect.

Have the four 1 gallon Baggies on a central table simply marked as mystery powders (A), (B), (C), & (D).

Have cups, bowls, towels, and measuring devices either at a central station or already at the individual tables. This will depend on your own personal management style.

Preferably, the students will be grouped in tables of four. Use cooperative role assignments to help with the efficiency of distribution. Possible roles could be:

Getter - the person who gathers the materials and brings them back to the group.

Recorder - the person who records all experimental steps and measurements.

Reporter - the person who shares information and results with the rest of the class.

Organizer - the person who assigns and runs the experimentation as well as keeping everyone in the group involved and interested.

Introduction:

Read the Children's book Oobleck by Dr. Suess to page 17. At this point in the book it is the morning after the magicians have concocted Oobleck and have sent it up to the sky. Bartholomew is concerned as he sees tiny green flecks in the sky.

Using a small amount of pre-made Oobleck, explain to the students that when you woke up this morning you found this on your front porch as you were getting the paper. You experiment with it and discover its unusual properties. (Demonstrate this to the class) You compare its properties to something familiar (a plate of water) and have students compare differences.

Explain that you went to your next door neighbor's house and they had found the same thing several days prior, except that it looks like this now (a Ziplock Baggie full of dried Oobleck). Finish the scenario by introducing four different powders which you and your neighbor think might possibly be the correct powder for making Oobleck.

Explain to the students that their job for the day is two fold: A) From the dried or dehydrated Oobleck find the proper ratio for mixing Oobleck; B) Determine which powder is the Oobleck powder using the previously determined ratio of water to powder mixture.

Procedure:

1. Follow introduction

2. Have the getters obtain a 3 oz. cup of dehydrated Oobleck and allow the group to experiment and discover the ratio of water that it takes to make the right consistency for Oobleck.

3. Have the groups then explore the other powders discerning which powder is the "real" Oobleck using the ratio previously determined from the dehydration experiment.

(Note: The baking powder will form a harmless chemical reaction "fizz" that produces C02 gas when water is added. Students should wear safety goggles and should not consume the "fizzing" mixture.)

4. Once the correct powder has been discovered, hand a box of corn starch to each group and allow them to make and explore with Oobleck for a while.

5. Give a warning for clean up and distribute small baggies for students to take their Oobleck home in. Explain to them that if it dries out, all they have to do is add water!!

6. Debrief the lesson for process and content science. Younger students may explain Oobleck as a state of matter. Older students could use their knowledge of emulsions, colloids, and solutions to determine the Oobleck substance. Even older children could explore the molecular structure of starch and diagram Oobleck as a polymer substance with unique properties.

7. A writing/journal assignment is an appropriate assessment to have students bring personal closure to their experience with Oobleck.

Background Information and Terminology:

Solution - A mixture of one substance scattered evenly and homogeneously throughout another substance, usually a liquid, which does not separate over time. Sugar and water is one example. The test of a homogeneous solution is that a sample taken from the top will have exactly the same amounts of each substance as an equal sample taken from the bottom. In the sugar water example sugar is the solute and the water is the solvent. They spread evenly through a process called diffusion.

Suspension - Some mixtures, such as mud and water, contain particles that are heavy enough to settle to the bottom after being stirred up. This kind of mixture is called a suspension because the material is only suspended temporarily in the liquid. It is possible to separate the liquid from the large solid particles in a suspension by letting the particles settle and then by pouring off the liquid. This is a process called decanting.

The main difference between suspensions and solutions is the size of the particles of the solute phase. In a solution, solute particles are approximately the size of molecules. In a suspension, the particles are large enough to be filterable.

Colloid - A gel, or a combination of two or more substances so that very small particles of each are suspended throughout the others. Examples are gelatin, milk, protoplasm in a cell, India ink, and varnish. The particles in a colloid are larger than a molecule (as in a solution) but small enough to remain in suspension permanently and be homogeneous.

There is a simple test to determine if a substance is a colloid or a solution. This test utilizes the Tyndall Effect. The particles in a colloid are large enough to act as tiny mirrors and reflect or scatter light (thus defining the Tyndall Effect). If you pass a beam of light through a colloid, you can see the beam or the Tyndall Effect. A solution will not give the Tyndall Effect. The Tyndall Effect can also be visualized in air when sunlight comes in through a window and the dust and other particles can be seen floating in the air; however, the air molecules are too tiny to be seen.

Immiscible liquids are two liquids such as oil and water that do not mix and will separate into layers. When a third substance is added to the mixture of oil and water (such as paprika), it will prevent the oil droplets from coming together and will not separate into layers causing an emulsion.

Emulsion - A combination of immiscible liquids in which droplets of one liquid are suspended throughout the other liquid. Examples of emulsions are mayonnaise and ice cream.

References:

Cobb, Vicki (1972). Science Experiments You Can Eat. J. P. Lippincott Pub. New York, New York.

Kenda, M & Williams, P. (1992). Barron's Science Wizardry for Kids. Scholastic Inc. New York, New York.

AIMS (1989). Oobleck. Lawrence Hall of Science. Berkeley, California.

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