Final answer:
Shampooing is the activity aimed at cleansing the scalp and hair by removing unwanted dirt, oils, and product build-up, typically using surfactants found in shampoo.
Step-by-step explanation:
Cleansing the scalp and hair by removing dirt, oils, and product build-up is a purpose of shampooing. When you shower or bathe, using shampoo, which contains surfactants like sodium lauryl sulfate or sodium laureth sulfate, helps to remove the unwanted build-up of sebum as well as dirt and oils from your hair and scalp. The process includes applying shampoo to wet hair, massaging it into the scalp, and rinsing it out, sometimes followed by conditioner.