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  • Provide people who want to know the pH levels of the household items they use with an easy and accessible method of testing pH. (a home pH test kit)
  • Test the pH level of household foods and items using natural indicators.
  • Determine the accuracy of natural indicators using a predetermined scale.

           Almost everything people encounter everyday contains an acid or base. The vast majority of foods is either slightly acidic or slightly basic. Acids taste sour, while bases taste bitter; bases are also slippery to the touch. Many essential processes in the human body require certain acid-base reactions. All body fluids must maintain a certain pH level to work properly. Stomach acid is highly acidic, while saliva, blood, and tears are fairly neutral.

           While acids and bases are indeed helpful and even crucial for everyday life, they can also be extremely harmful. Very concentrated acids or bases can burn or corrode just about anything they come in contact with. Therefore, the strength of an acid or base is useful knowledge. Many household cleaners contain strong bases to remove oily soils, but too strong a base causes corrosion. Vinegar and soda are both acids, but not strong enough acids to eat through skin or cause permanent eye damage.

           pH levels serve as a large factor in determining the extent of damage an acid or base can cause, but other chemicals in the substance can alter observations and conclusions based solely on pH level. To narrow down the topic for the experiment, only the pH levels of substances will be taken into consideration.

           The pH scale (from 1-14) represents the concentration of the hydronium ion, which determines the strength of the acid or base, 1 being the strongest acid and 14 being the strongest base. Litmus paper, pH meters, pH paper, and indicators are used to determine the pH level of a substance. All indicators will change color at specific pH levels. Common chemical indicators include thymol blue, methyl red, bromthymol blue, and phenolphthalein.

           Now what if someone wants to find the pH level of a substance but lack the proper lab equipment and chemicals? Because chemical indicators are hard to obtain in the home environment, natural indicators can be substituted in their stead. Good natural indicators include red cabbage, red beets, grapes, strawberries, blueberries, hydrangeas, and hollyhocks. These plants produce antocyanines, a type of pigment, which causes color changes within certain pH levels. For the experiment, at least 4 indicators will be used to ensure a more accurate pH reading.

           Once the pH level for the household item is established, then the effects of that concentration of acid or base can easily be found. In this way, people can readily find out what exactly are the hazards involved in the foods they eat or cleaners they use. To create a quality home pH test kit, the accuracy of the indicators must be examined. Otherwise, the point of testing the pH levels of household items will be undermined by inaccurate data.

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