How does the addition of soap to water affect its surface tension?

How does the addition of soap to water affect its surface tension?

Step 1: Understand what surface tension is. Surface tension is the force that makes the surface of water behave like a stretched elastic sheet.
Step 2: Know that water molecules are attracted to each other. This attraction creates strong cohesive forces that keep the water molecules together.
Step 3: Learn that when soap is added to water, it mixes with the water molecules.
Step 4: Realize that soap molecules have a special structure. One part of the soap molecule likes water (hydrophilic) and the other part does not (hydrophobic).
Step 5: Understand that the soap molecules disrupt the cohesive forces between the water molecules. This means the water molecules are not as strongly attracted to each other anymore.
Step 6: Conclude that because the cohesive forces are weakened, the surface tension of the water decreases when soap is added.

Surface Tension – Surface tension is the elastic tendency of a fluid surface that makes it acquire the least surface area possible, primarily due to cohesive forces between liquid molecules.
Effect of Surfactants – Surfactants, like soap, reduce surface tension by interfering with the cohesive forces between water molecules, allowing for easier spreading and mixing.