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Guilherme Mazui

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What is the Difference Between Adhesion and Cohesion?

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Adhesion and cohesion are properties that describe the attraction between molecules or atoms, playing a crucial role in various natural phenomena and applications. The main differences between adhesion and cohesion are:

  1. Molecules involved: Adhesion is the attraction between the molecules of two different substances, while cohesion is the attraction between the molecules or atoms of the same substance.
  2. Force types: Adhesion forces can result from electrostatic forces exerted on different molecules, while cohesive forces are associated with Van der Waals forces and hydrogen bonding that cause liquids to stick to each other.
  3. Examples: Water is a substance that exhibits both adhesive and cohesive properties due to the polarity of its molecules. Cohesion causes water molecules to stick to each other and form a sphere, while adhesion allows water to stick to other surfaces, such as the walls of a glass container.

Examples of adhesion and cohesion in action include:

  • Capillary action, which involves the adhesive and cohesive forces acting together to lift water against the force of gravity in narrow tubes.
  • The movement of water through plants from the roots to the tips, driven by cohesion and adhesion forces.
  • The functioning of glue, paint, tar, and other adhesive substances, which rely on adhesion forces.
  • Wicking in synthetic fibers, which uses capillary action by adhesion and cohesion forces to remove sweat from the skin.
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  • What is the Difference Between Adhesion and Cohesion?
  • Comparative Table: Adhesion vs Cohesion

    • Comparative Table: Adhesion vs Cohesion

    Here is a table comparing the differences between adhesion and cohesion:

    Property Adhesion Cohesion
    Definition The tendency of two or more different molecules to bond with each other. The force of attraction between the same molecules.
    Type of Molecules Different molecules or surfaces. Like molecules (of the same substance).
    Attraction Type Electrostatic forces. Van der Waals forces and hydrogen bonding.
    Examples Adhesion is used for the proper functioning of glue, paint, tar, cement, ink, etc.. Water molecules stick to each other to form a sphere, wetting of a paper towel, water flowing up from the roots to the tip of a plant.
    Capillary Action Adhesive and cohesive forces act together to induce capillary action, which is the principle used in lamp wicking and synthetic fibers wicking sweat away from the skin. Both adhesive and cohesive forces act on the surface of the water, with strong cohesive forces causing the liquid to form a convex surface, while strong adhesive forces cause the liquid to spread over the surface.

    In summary, adhesion is the attraction between different molecules or surfaces, while cohesion is the attraction between molecules of the same substance. Both forces play a crucial role in various phenomena and applications, such as capillary action and the properties of water-based substances.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.