Why are there bubbles in shampoo?

Bubbles in shampoo are created due to the presence of surfactants, which reduce the surface tension of water and allow air to mix with the liquid. When the shampoo is agitated, such as during application, these surfactants trap air, forming bubbles. Additionally, the lathering action helps to cleanse the hair and scalp by lifting dirt and oils. The presence of bubbles is often associated with the effectiveness of the product in cleaning.