Environmental pH
Introduction:
A liquid may be an acid, base, or neutral. The degree of acidity or basicity can be
measured by using the pH scale. The scale is divided into three areas: Acid (readings
below 7), neutral (reading of 7), and basic (readings above 7). Each division either
increase or decreases the pH of a substance 10 times. The pH of 5 is ten times more
acidic than a pH of 6. Water has a pH of 7 but when it mixes with air the suspended
materials will either raise or lower its pH. Acid Rain is an example of this type of
reaction.
Objective:
The student will determine the pH of various substances and will also determine how
some of these substances can affect the environment.
Materials:
 pH paper and
 10 depression
 Pond Water
Chart
slides
 Distilled Water
 Forceps
 Lemon Juice
 Salt Water
 Masking Tape
 Cola
 Tap Water
 Paper Towels
 Ammonia
 Baking Soda
 Detergent
Procedure:

Create a data table in you lab book with the following information:
Station
Hypothesis
pH
Acidic
Basic
Neutral

Make a hypothesis about the pH of each of the substances below, record this
information in your data table
o Station A - Lemon Juice
o Station B- Distilled Water
o Station C- Pond Water
o Station D- Tap Water
o Station E- Salt Water
o Station F- Ammonia
o Station G- Baking Soda
o Station H- Cola
o Station I-Detergent.


For each lab station:
Touch the pH paper to the liquid and compare the color of the paper with that on
the pH chart.
Record your observation in your data table. Mark if the substance is acidic, basic,
or neutral.
Rotate to the next station and repeat the procedure.
Continue rotating through the stations until you have observed each of the
substances.



Analysis: Answer the following questions.
1. Which of the liquids had the lowest pH ?
2. Which of the liquids had the highest pH?
3. Which of the liquids were closest to being neutral?
**** Draw a line representing the pH scale and place the substances tested on the scale
4. If the pH of a sample was 3 how many times more acidic is it than a solution with a pH
of 6?
5. How might one correct the pH of a lake with a reading of 3?
6. What is the pH of human skin?
7. How does non-tearing shampoo work?
8. What is the pH of rain water?
9. What local industries pump materials into the atmosphere to create a drastic pH change
in rain water?