Ever wonder whether your coffee is acidic or not? How about your tap water? We’re testing the pH of 10 Common Household Liquids using a digital pH meter.
What is pH? Historically, as written in older chemistry papers, pH stands for "potential of Hydrogen" (some sources say it might have been "potenz" or "power of Hydrogen" or "pondus or quantity of hydrogen")—but what does that actually mean? What do we use this for?
pH is a way to measure the relative strengths of acids and bases. In general, acids increase the concentration of H+ ions in a solution, while bases decrease the concentration of H+ ions in a solution. If you’re concerned about safety, what you really want to know is the pH. The pH scale runs from 0 to 14. Acids have a pH less than 7. Bases have a pH greater than 7. The farther you are from 7, the stronger the acid or base is.
The equation to calculate pH from the concentration of hydrogen ions is
pH = -log[H+]
It's a base 10 logarithmic scale, where something with pH 5 is 10 times more acidic than something with pH 6. pH7 is neutral, and anything with a pH greater than 7 is considered basic (or alkaline), and anything with a pH less than 7 is considered acidic.
We started this video with a quick review of the definition of acid and base, consider whether water is an acid or a base, and then work 3 examples of using the equation for pH. This second video about pH is a look at the pH of common household liquids. You may be surprised!
Video 1: Calculating pH
Video 2: Household pH
Handout: Calculating pH Video Notes Worksheet
Handout: Household pH Video Notes Worksheet
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