Cohesion and adhesion are two important properties of liquids that describe how they interact with themselves and other substances.
Cohesion:
- Cohesion refers to the attractive forces between like molecules. In simpler terms, it's the tendency of molecules of the same substance to stick together.
- Example: Water molecules are attracted to each other due to hydrogen bonding, which leads to high surface tension and the formation of droplets.
Adhesion:
- Adhesion describes the attractive forces between unlike molecules. It's the tendency of molecules of different substances to stick together.
- Example: Water molecules adhere to glass molecules, causing water to "wet" the surface of a glass.
Key Differences:
| Feature | Cohesion | Adhesion |
|---|---|---|
| Attraction | Between like molecules | Between unlike molecules |
| Example | Water molecules sticking to each other | Water molecules sticking to glass |
| Effect | Surface tension, droplet formation | Wetting, capillary action |
Practical Insights:
- Cohesion is responsible for the surface tension of liquids, which allows insects to walk on water.
- Adhesion is responsible for capillary action, which allows water to travel up narrow tubes or spaces against gravity.
Conclusion:
In essence, cohesion is the stickiness of a substance to itself, while adhesion is the stickiness of a substance to something else. Both properties play crucial roles in various natural phenomena and everyday applications.
