What Is Life? — The Beating Oleic
Acid Organism
Introduction
SCIENTIFIC
BIO FAX!
If an object moves, responds, eats, pulsates, and exhibits other characteristics of life, is it alive? Create a pulsating
“chemical” organism to introduce the characteristics of life.
Concepts
• Characteristics of life
• Chemical stimulation
Materials
Ammonium hydroxide solution, NH4OH, 1 M, 25 mL
Liquid
Ivory®
soap, 5 mL
Beral pipet
Graduated cylinder, 10-mL
Oleic acid, 3 drops
Overhead projector and screen
Peanut oil, 10 mL
Petri dish, bottom
Distilled water, 100 mL
Stirring rod
Beaker, 100-mL
Safety Precautions
This activity requires the use of hazardous components and/or has the potential for hazardous reactions. Ammonium hydroxide solution
is irritating to eyes and skin. Wear chemical splash goggles, chemical-resistant gloves, and a chemical-resistant apron. Please review
current Safety Data Sheets for additional safety, handling, and disposal information. Wash hands thoroughly with soap and water
before leaving the laboratory.
Preparation
1. Prepare an Ivory soap/water solution. Add 5 mL of Ivory soap in a 100-mL beaker and dilute to 100 mL with distilled
or deionized water. Mix thoroughly.
2. Prepare the oleic acid/peanut oil solution by adding three drops of oleic acid to 10 mL of peanut oil in a 10-mL graduated cylinder.
Procedure
1. Place a bottom of a Petri dish on the stage of an overhead projector. Add 25 mL of the 1 M ammonium hydroxide
solution, NH4OH, to the Petri dish.
2. Add 5 mL of the liquid Ivory soap solution to the Petri dish and mix with a stirring rod.
3. Place 10 mL of the oleic acid/peanut oil solution on the surface of the soap/ammonium hydroxide solution. For best
results, disperse the oleic acid/peanut oil solution over the entire surface of the soap/ammonium hydroxide solution.
4. Have students observe the reaction taking place in the Petri dish by watching the reaction on the overhead image.
Disposal
Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures governing the disposal of laboratory waste. The final solution may be disposed of according to Flinn Suggested Disposal Method
#26b.
© 2016 Flinn Scientific, Inc. All Rights Reserved.
Publication No. 10300
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What Is Life? — The Beating Oleic Acid Organism continued
Tips
• Solutions may be prepared in advance but should be kept in separate, tightly closed containers until the time of the demonstration.
• Be sure to use a very clean Petri dish.
• As soon as the oleic acid/peanut oil solution is added, the oil slick formed should start to pulsate. If it doesn’t, add another drop of oleic acid.
• If air is blown across the surface, the slick will contract.
• As the ammonia/soap solution warms on the overhead projector, the pulsations will become stronger.
Discussion
This is a great activity to introduce and discuss the characteristics of a living organism. Once this demonstration is complete,
ask students if the oleic acid/peanut oil solution is really alive. Discuss and ask the students to define what types of traits are
required to be considered alive (made of cells, grow and develop, obtain and use energy, respond to the environment, reproduce). Does the oleic acid/vegetable oil solution possess all or some of these traits?
As an extension to this activity, have students identify other materials (such as rocks and minerals, mosses or lichens, microscopic cells, coral, viruses, etc.) as living or non-living. Ask students to form groups and compile lists of other items and have
students classify the objects as living or non-living.
The cause of the movement in the dish is not entirely known but is probably due to three factors; the lack of solubility of the oil
in the water, the differences in the surface tension of the two liquids, and the evaporation of the ammonia from the surface.
Connecting to the National Standards
This laboratory activity relates to the following National Science Education Standards (1996):
Unifying Concepts and Processes: Grades K–12
Evidence, models, and explanation
Content Standards: Grades 5–8
Content Standard B: Physical Science, properties and changes of properties in matter
Content Standard C: Life Science, structure and function in living systems
Content Standards: Grades 9–12
Content Standard B: Physical Science, chemical reactions
Content Standard C: Life Science, matter, energy, and organization in living systems
Acknowledgments
Special thanks to Alan Chang, Glencoe High School, Hillsboro, Oregon for providing the concept for this demonstration.
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© 2016 Flinn Scientific, Inc. All Rights Reserved.