The pH Scale measures the strength of an acid or a base
(alkaline) in solution
Slide 3
Lets review the characteristics of acids and bases (alkalines):
Acids Taste sour (think lemons) React with some metals to give off
hydrogen gas Turn blue litmus indicator paper red Neutralize bases
to produce a salt and water Give off or donate H+ ( hydrogen ions)
Bases Taste bitter, but most are toxic to humans (think cleaning
products) Feel slimy or slippery, like soap Turn red litmus
indicator paper blue Neutralize acids to produce a salt and water
Accept H+ (hydrogen ions)
Slide 4
We can use the PH Scale to add to our list of characteristics:
Acids have a pH lower than 7 the lower the pH number the stronger
the acid Bases have a pH higher than 7 the higher the pH number the
stronger the base Distilled water is neutral with a pH of 7
Slide 5
Keeping the characteristics of acids and bases in mind, what do
you think pH stands for in the pH Scale? Proven Hypothesis? Try
again! Possibly Harmful? Nope Heres a hint H+ YES! pH stands for
potential Hydrogen!
Slide 6
Take a look at where these familiar acids and bases belong on
the pH Scale:
Slide 7
Please read the directions in the orange boxes and then click
on the central image to activate this science simulation.
Experiment until you can answer the following question: What is the
pH of.5 Liter of battery acid after you dilute it with.5 Liter of
water? Record your answer on an index card it will be tomorrows
ticket in the door! Add water to your solution with the blue knob
Choose an everyday liquid from the drop down list Use the dropper
to add more of your liquid Empty the beaker here to start over Drag
the probe into your solution to measure the pH
Slide 8
In closing, enjoy this music video while you ponder the
following questions for tomorrows discussion. If you spilled
ammonia on your arm would you wash it off with soap? Why or why
not? Tums has a pH of 8.5 and gastric (stomach) acid has a pH
ranging from 1.5 to 3.5 when we eat Tums what (2 things)does some
of our gastric acid turn into? Should chemists make music
videos?
Slide 9
References Blais,T. (2014, Nov. 6 th ). All about that base (no
acid). Retrieved from: https://www.youtube.com/watch?v=IAJsZWhj6GI
pH Scale: Basics simulation : PhET Interactive Simulations
University of Colorado http://phet.colorado.edu.
http://phet.colorado.edu