Cohesion
1. Vocab and Facts
Cohesion- The property that holds molecules of a substance together.
Adhesion- The property that holds molecules of different substances together.
Surface Tension- The tendency of a liquid's surface to resist rupture when placed under tension or stress.
- Both cohesion and adhesion come from the root word "hesion" which means to stick
- Cohesive attraction holds molecules of a substance together
- Cohesion is caused by an inter-molecular attraction
- Cohesive forces cause surface tension
2. Pictures of Cohesion
This picture shows mercury in a glass. It demonstrates cohesion because the drop of mercury is holding its form. This picture also demonstrates that although cohesion is associated specifically with water it is not limited to water.
This picture shows a drop of water on a leaf. Like the Mercury the water drop is holding its form.
This diagram shows two particles being attracted together because of cohesion.
3. Relation of Cohesion and Adhesion
Cohesion has to do with molecules of the same type being attracted to each other, but adhesion is when two molecules that are not the same are attracted to each other. When molecules are attracted to each other its like they are sticking to each other. Adhesion for example is how a liquid can be in a beaker, whereas cohesion is how molecules in the liquid hold together.