Adhesion vs. Cohesion

Adhesion
Cohesion

Cohesion is the property of like molecules (of the same substance) to stick to each other due to mutual attraction. Adhesion is the property of different molecules or surfaces to cling to each other. For example, solids have high cohesive properties so they do not stick to the surfaces they come in contact. On the other hand, gases have weak cohesion. Water has both cohesive and adhesive properties. Water molecules stick to each other to form a sphere. This is the result of cohesive forces. When contained in a tube, the water molecules touching the surface of the container are at a higher level (see Meniscus). This is due to the adhesive force between the water molecules and the molecules of the container.

Comparison chart

Edit this comparison chart

Adhesion

Cohesion

Constituents Dissimilar molecules Similar molecules
Effect Capillary action, meniscus Surface tension, capillary action and meniscus

Contents: Adhesion vs Cohesion

Cohesion causes water to form drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place.
Cohesion causes water to form drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place.

edit Effects of cohesion and adhesion

edit Surface Tension

Mercury exhibits more cohesion than adhesion with glass
Mercury exhibits more cohesion than adhesion with glass

Surface tension is the result of cohesive forces between adjacent molecules. The molecules in the bulk of a liquid are pulled equally in all directions by the neighboring molecules. But the surface molecules do not have molecules on all sides. Hence they are pulled inwards causing the liquid to shrink to form a surface with minimum area, a sphere. Hence water droplets are spherical.

Water molecules bead together on a wax paper because surface tension is greater than the adhesive forces between the paper and water molecules.

The surface tension of water allows objects heavier than it to float across it. When water molecules do not stick to the object (non-wettable) and the weight of the object is less than the forces due to surface tension.

edit Meniscus

Concave and Convex Meniscus. The meniscus is concave when adhesive forces are stronger than cohesive forces. e.g. water. It is convex when cohesion is stronger. e.g. mercury
Concave and Convex Meniscus. The meniscus is concave when adhesive forces are stronger than cohesive forces. e.g. water. It is convex when cohesion is stronger. e.g. mercury

The curved surface of a liquid inside a container is the meniscus.

edit Capillary action

Capillary action is the result of cohesive and adhesive forces. When a liquid flows through a narrow space, the cohesive and adhesive forces act together to lift it against the natural force of gravity. Wetting of a paper towel, water flowing up from the roots to the tip of a plant are a few examples of capillary action.

edit Applications

Adhesion is used for the proper functioning of glue, paint, tar, cement, ink etc. Adhesive and cohesive forces together induce capillary action which is the principle used in lamp wicks. Synthetic fibers use wicking to remove sweat from the skin.

edit References

Share this comparison:

If you read this far, you should follow us on:

"Adhesion vs Cohesion." Diffen.com. Diffen LLC, n.d. Web. 23 Jul 2014. < http://www.diffen.com/difference/Adhesion_vs_Cohesion >

Stay informed Related Comparisons
Follow Diffen
Make Diffen Smarter.

Log in to edit comparisons or create new comparisons in your area of expertise!

Sign up »
Top 5 Comparisons Recently Compared

Comments: Adhesion vs Cohesion

Comments via Facebook

Anonymous comments (2)

May 25, 2014, 11:37pm

tanks a lot

— 107.✗.✗.184
0

October 8, 2013, 3:01pm

To a degree this definitely helps you, but some people are just looking for simple answers, not a speech.

— 69.✗.✗.254
0

share

Up next

Diffusion and Osmosis