Florida Barber License Practice Test

Which part of the shampoo molecule attracts water and repels dirt?

1. Hydrophilic tail

2. Hydrophobic head

3. Repellent molecule

4. Adhesive component

The correct answer is: Hydrophilic tail

The correct answer is that the hydrophilic tail of the shampoo molecule is responsible for attracting water and repelling dirt. In the context of shampoo, the term "hydrophilic" refers to a part of the molecule that is water-attracting. This characteristic is crucial because shampoo needs to interact with both water and dirt to effectively cleanse the hair and scalp. When shampoo is applied, the hydrophilic tail binds with water molecules, allowing the shampoo to mix easily and spread throughout the hair. This interaction helps dissolve and wash away dirt and oil, which are typically not water-soluble. Meanwhile, the hydrophobic part of the shampoo molecule works to capture these dirt and oil particles. This dual action, where the hydrophilic part attracts water and interacts with the hydrophobic dirt and oils, allows for effective cleaning. Understanding this molecular behavior is fundamental for barbers and cosmetologists, as it highlights the importance of proper shampoo selection based on hair types and cleansing needs.