What is pH?

Mauricio Gonzalez

Frederick Douglass Academy, Manhattan

Summer Research Program for Science Teachers

August 2008


Subject: Biology

Problem of the day [warm up, review, quiz, or homework]:  (5 minutes)

In your notebooks, using complete sentences, describe what happens when you combine baking soda and vinegar? Chemical reaction, CO2 is released after Carbonic acid is created.


The students I teach range from the 6th grade to the 12th grade. The population is predominantly African American (>93). The next largest group is Latino. According to our students FDA is very challenging but is also very distracting. Our students have a general apathy toward the school probably because of its authoritarian philosophy. Notwithstanding, we never have the levels of violence that is seen at other schools in the city.


a. Compare the difference between mixtures and solutions.

b. Describe how pH determines how acidic and basic a solution is.

c. Determine the importance of pH in the natural world.

d. Narrate what pH means to you and how you think it affects the world.


mixture, solution, solute, solvent, enzymes, chemical reaction, base, acid, hydrogen ion, hydroxide ion, neutral


Lesson: (25 minutes)

1.     What is a chemical reaction? Atoms of molecules are rearranged when chemical bonds are created or destroyed.

2.     what is a mixture? Molecules mix but do not react chemically.

3.     what is a solution? Molecules mix in a chemical reaction.

4.     what is pH? The measure of hydrogen and hydroxide ions or equivalents in a solution.

5.     what is an acid? A solution with more hydrogen ions than hydrogen ions or their equivalents.

6.     what is a base? A solution with more hydrogen ions than hydroxide ions or their equivalents.

7.     what are examples of acids and bases? Lemon juice, ammonia, hydrated lime, vinegar, tap water, acid rain, etc.

8.     how does pH affect a chemical reaction? pH can speed up or slow down a chemical reaction and enzyme activity.

9.     how can pH affect the natural world? Because pH can affect the chemical reactions within an organism it is vital for life processes such as photosynthesis, respirarion, digestion, reproduction, growth, development, etc.


Practice: (15 minutes)

How can pH affect you? Write your answer in your note book in complete sentences. Explain your answers.


1.       Demonstrates an understanding of structure and properties of matter

2.       Demonstrates an understanding of chemical reactions.

3.       Demonstrates an understanding of the impact of technology

4.       Frames questions to distinguish cause and effect; and identifies or controls variables.