Chemistry+Expectation

Background knowledge
//__The pH of human skin__// There are variety of pH range for human adult skin, but it is generally between 4.6 -6. From the range of pH we can notice that it is weak acid. This is because we produce an acid mantle on our skin to protect ourselves from bacterias. Therefore if the pH of human skin becomes alkaline, those acid mantle will disappear and skin will dry. Also if the skin becomes alkaline, //Staphyloccoccus epidermidis//, one of the good bacteria on our skin which breaks down fatty acid, will be killed because it favors acidic environment of the normal skin.

Source: [|Importance of Your Skin's pH]

//__The chemicals in swimming pool__// The chemicals generally used to sanitize the swimming pool are "chlorine" type. Those chemicals are called chlorinating agents. Some examples of cholorinating agents are; Calcium hypochlorite (Ca(OCl)2·4H2O), lithium hypochlorite (LiClO), sodium hypochlorite (NaOCl), trichloroisocyanuric acid (C3Cl3N3O3), potassium dichloroisocyanurate, sodium dichlorocyanurate Since there chlorine (Cl), which makes strong acids, is one of the conponent of the chemical the pH of swimming pool is more acidic.

Source: [|OSH Answers: Swimming Pool Chemicals], [|Answers.com]

Hypothesis
The pH of each swimming pool water will be under 7 because the chemicals generally used to chlorinate the swimming pool are acidic. The buffer region of the swimming pool should be broad in order to protect human skin. And the buffer region should be under pH 7 because if it is over 7 the acid mantle on the human skin will be destroyed and the skin will be dry.