Kubic Bubbles

Author(s): Afrodita Fuentes/ Linda Heidenrich
Demonstration Equipment - Teacher's Guide
SED 695B

Principles illustrated:

  • Formation of soap films within geometrical figures
  • The cell membrane's fragility is similar to that of a soap film
  • Chemistry of soap and lipid molecules
  • Properties of water as a polar molecule: cohesion & adhesion
  • Water's Surface Tension

 

 

Kubik Bubbles: Geometric figures immersed in soap solution.
Films of soap can be formed within a variety of geometric figures. These films are very delicate and can can be disrupted easily with pressure, temperature, or lack of water. The cells that make up our bodies are surrounded and protected by membranes that are very similar to the films of soap.

Standards Addressed: Biology/Cell Biology:

1a. Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings.

1h. Students know most macromolecules (polysaccharides, nucleic acids, proteins, lipids) in cells and organisms are synthesized from a small collection of simple precursors.

Investigation & Experimentation:
d.Formulate explanations by using logic and evidence.
f. Distinguish between hypothesis and theory as scientific terms.
i. Analyze situations and solve problems that require combining and applying concepts from more than one area of scien

 
 
Materials

Kubic Bubbles Kit

2-3 gallons of water

1 cup of dishwashing soap or detergent

container to hold the soap solution and allow dipping of the geometric frames.

Explanation of Principles Involved

Chemistry and structure of soap and lipid molecules

Soap bubbles and fat/lipid bubbles (micelles) look alike because their chemistry and struture are siilar. Their molecules have a long nonpolar hydrocarbon chain with a highly polar oxygen-rich group atthached to the end. Their hydrocabon long tail is hydrophobic (water insoluble) and their oxygen end is hydrophilic (water soluble).

Notice the soap bubble and its chemistry on the left. Ttwo layers of soap molecules surround a layer of water molecules. The hydrophilic heads of the soap molecules are facing the water molecules and the hydrophobic tails are facing away from the water molecules.

Mosaic-model of the Cell membrane. Notice the two lipid layers, along with proteins and carbohydrates that make up the cell membrane. The hydrophobic tails of the lipid molecules are facing each other away from the cells' cytoplasm and external environment which contain water. The hydrophilic heads are facing the cell's internal and external environment.

 
   
 

Procedure:

Preparation of the soap solution

  1. Place some cold water in a container, to a level that will allow the framweworks to completely immerse
  2. Pour a cup full of liquid soap into the bowl
  3. Stir the mixture while avoiding production of bubbles on the surface of the soap solution
  4. Remove any bubbles that may have formed with a tissue of cloth

Assembly of soap film frameworks

  • Formation of shapes of soap film
  • Immerse the frameworks completely while holding it by the handle
  • Withdraw the framework by the handle & a sopa film forms inside the framework

Other Variations: If the framework is withdrawn by a corner first, different and unique geometrical soap films will be observed.

 

Applications:

Math: When using the geometric figures, area and angles formed by the solid geometric figures as well as the soap films can be measured.

Physics: demostration of light reflection can also be accomplished with the films of soap that form withint the geometric structures.

**Radiolaria are holoplanktonic organisms in the oceans with a radial/geometrical symmetry. The formation of their bodies is determined by surface tension forces, in a similar way to the formation of bubbles. Their abundance indicate water quality that includes salinity, acidity, productivity, and nutrient availability (these are also factors that can affect the stability of soap films).

 

References & Links: