Hair is one of the most prominent features of a person’s appearance. It’s a vital part of human reproduction and communicates messages such as gender, social status and age. Even societal roles are dictated by the way a person dresses their hair. Humans have used shampoo since the 1920s to wash and remove unwanted hair. Shampoo has become a necessary part of daily life because hair plays such an integral role in human nature.

The way we define water has changed drastically throughout history. Ancient Greek philosophers believed water was a solid and that steam was the natural element’s natural motion. Today, however, we understand that all water is made up of molecules. Water’s molecular structure consists of two hydrogen atoms and one oxygen atom. The electrons in its molecule are arranged in a covalently bonded pattern— the opposite of molecules like nitrogen, carbon and other elements with unpaired electrons. This ordered arrangement is what makes water such a great conductor of heat and electricity. Additionally, water can hold a large quantity of substance without changing its shape or composition. For example, water is used as a solvent for gels and other materials, which can be difficult to remove from skin without damaging hair follicles.

Hair dye is usually removed using a mixture of water and a mild shampoo. After washing out the dye with regular soap, rub the hair with water to remove remaining dye particles and residue from the shampoo. The next step is to rinse the hair with clean water to remove excess shampoo from it. Finally, apply a light conditioner to the hair shaft to seal in the results and prevent further clumping of hair particles during drying. As this process shows, hair is usually absorbent enough to handle a single cleansing step with only water. However, multiple steps result in better removal of unwanted hair colors from the scalp and hair follicles— especially when using specific shampoos for each step.

Human nature dictates that humans will find ways to make use of water's natural properties. This applies not only to physical aspects like shaving but also to more intangible aspects like how we interpret beauty through hairstyles and hair color choices.  Without the usefulness of water in our daily lives, many processes associated with maintaining physical health would be much more difficult or impossible.