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Michelle Sperle-BergAmerican College of EducationCHEM 5313Dr. Ken CappsMarch 17, 2024

Viscosity Experiment

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Viscosity is the resistance of a liquid to flow. The viscosity of a liquid is a manifestation of the intermolecular forces within the substance. The stronger the IMFs the more viscous the substance. (Amercan College of Education, 2017)


The viscosity of different substances can easily be compared using experimental techniques. A drip cup (or Zahn Cup) is used to measure the viscosity of paints or glazes. A given volume of the paint flows out of the hole at the bottom of the cup, the flow time is recorded, and that time indicates the viscosity of the material (Gebhart, 32012). A variation of a drip cup will be used in the experiment presented here.

Comparing Viscosities

This experiment will compare the viscosity of 3 diffferent liquid detergents. The viscosity of the liquid detergent is important to consumers as effectiveness of the soap is often correlated with viscosity. A liquid soap with a watery consistency is viewed as less concentrated, containing less of the active ingredients used to clean food and grease from surfaces.

Experiment Design

Car soap & wax. . Premium Brand

Dish soap, Premium brand.

Dish soap, Dollar Tree Brand

ArmorAll Wash & Wax

Dawn Dishwashing Soap

Ultra Deluxe

Viscosity Experiment Video

(Xie, 2023)

  • use of thickening agents
  • temperature
  • pH
  • amounts and types of formulation components
  • amount of added water

Factors that influence viscosity of liquid detergents include:

An ideal detergent should have a suitable viscosity to effectively deliver its cleaning products. If the viscosity is too high, it can hinder the ease at which it flows out of the container and dissolves in water. If the viscosity it too low, it may be unstable or may not effectively remove dirt and stains.

The Basics of Liquid Detergent Viscosity

The amounts and types of solvents, additives, and surfactants are combined to produce the desired viscosity.




Basic Detergent Ingredients

  • First ingredient is water (solvent) which accounts for its low viscosity.
  • Surfactant: Sodium Lauryl Sulfate, Lauramine Oxide
  • Thickener: Lauramine Oxide, Sodium chloride

Ultra Deluxe

Contains less solvent and more surfactants and emulsifiers resulting in higher viscosity

  • Last ingredient is water (rather than first). Also has alcohol as a solvent
  • Surfactants/Emulsifiers: Alkyldimethylamine Oxide, C9-11 Pareth 8, Deceth 8, PEG 14 PEG-24 PPG 16 Copolymer, Sodium Lauryl Sulfate
  • Thickener: Sodium Chloride


The dispersion forces of the wax contributes to the viscosity of the product. The surfactants are necessary to dissolve the wax in the solvent.

  • Ingredients are proprietary but does contain wax.
  • Waxes are large nonpolar compounds that are highly hydrophobic which accounts for the water repellent properties of the product. Wax molecules are bonded together by London Dispersion Forces.
  • Contains the surfactants, sodium olefin sulfonate, and benzenesulfonic acid (Consumer Product Information Database, n.d.).


Liquid detergents are mixtures. Each detergent is formulated with specific ingredients blended in unique amounts depending on the manufacturer's preferences. The Dollar Store (Delux) brand is the least viscous. This is due to the large amount of water in the product.

Dawn Dishwashing Detergent is a high quality brand known to be a very effective product. Dawn was shown to be the most viscous of the three brands. It is also the most expensive of the three brands tested.

Finally, the ArmorAll Car Wash was moderately viscous. Because it is a proprietary recipe, little is known about the ingredients and amounts of substances in the product, including the amount of solvent. It is assumed that the wax in the product enhances the viscosity of the product.


Consumer Product Information Database. (n.d.)


Rausch, W. (n.d.). Soaps and detergents. Virtual Textbook of Organic Chemistry.

Xie, J. (2023). A comprehensive guide to liquid detergent viscosity: understanding the importance, factors, and applications. YeserChem. https://yeserchem.com/a-comprehensive-guide-to-liquid-detergent-viscosity-understanding-the-importance-factors-and-applications/

Tro, N. (2023). Chemistry A Molecular Approach. (6th Edition). Pearson Education

Gebhart, T. (2012). Viscosity. Ceramics Monthly, 60(10), 14–17.

American College of Education. (2017). Chem 5313 Systems of Chemistry Module 4 [Part 1 presentation]. Canvas. https://ace.instructure.com/courses/1958779/external_tools/118428


(Tro, 2023)

Molecule SizeThe larger the molecule, the larger the magnitude of dispersion forces. Larger molecules also have more surface area for interactions to occur resulting in the possibility of becoming entangled.

Other Factors Affecting Viscosity

TemperatureAs temperature increases, viscosity decreases. Thermal energy overcomes intermolecular forces and allows molecules to move past each other more easily.

The job of a surfactant is to change the surface properties of water. Surfactants reduce water's surface tension by breaking the hydrogen bonding between water molecules. The polar (or sometimes ionic, depending on the type of detergent) heads of the surfactant hydrogen bonds with the water while the nonpolar hydrocarbon tails form dispersion forces with the nonpolar grease or food. The hydrophobic tails group together forming micells surrounding the grease and washing it away (Reusch, n.d.)Surfactants come in various types. The combinations and ratios of the different types of surfactants in a detergent effects its viscosity. Surfactatns can also act as emulsifiers keeping immiscible components from settling out of the solution. (Xie, 2023).


Polar Heads & Nonpolar Tails

Water and Alcohols

Solvents are added to dissolve or dilute other ingredients. Typically, solvents reduce the viscosity of the detergent because they interrupt the IMFs between other molecules that contribute to higher viscosity (Xi, 2023).


Additives can either increase or decrease the viscosity of the detergent depending on their interaction with surfactants and solvents. Additives do not typically contribute to the effectiveness of the product (Xie, 2023)


Thickeners, Fragrances, Colorants, Preservatives