environmental pH

Environmental pH 

Introduction:

A liquid may be an acid, base, or neutral. The pH scale can be used to measure how acidic or basic a solution is. 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.

Problem:

Students will determine the pH of various substances and their effect on organisms in the environment.

Materials:

Wide range pH paper and chart, spot plate, forceps, soapy water, lemon juice, ammonia, cola, distilled water, pond water, salt water, baking soda solution, 8 dropper bottles.

Procedure:

  1. Using a spot plate, place a couple of drops of each solution into the numbered wells being careful NOT to mix solutions. (Well 1- soapy water, well 2- lemon juice, well 3- ammonia, well 4 – cola, well 5 – distilled water, well 6 – pond water, well 7 – baking soda solution, well 8 – vinegar))
  2. Pick up a piece of pH paper with forceps.
  3. Touch the pH paper to the liquid in well # 1 and remove it.
  4. Compare the color of the pH paper to the pH color chart.
  5. Record the pH on your data table.
  6. Use a new piece of pH paper each time, and repeat steps 2 – 5 for each of the other solutions.

Data:

Solution pH Acidic Basic Neutral  
Soapy water        
Lemon juice        
Ammonia        
Cola        
Distilled water        
Pond water        
Baking soda        
Vinegar        

Analysis:

1. Which liquid had the lowest ph?

2. Which of the liquids had the highest pH?

3. Which of the liquids was closest to being neutral?

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 someone correct the pH of a lake with a reading of 3?

 

 

6. What would be the pH of human blood?

 

7. How does non-tearing shampoo work?

 

8. What would be the likely pH of acid rain?

9. What industries in our area pump materials into  the atmosphere to create a drastic change in rain water? (Hint: Some days you can smell this industry.)

 

 

10. List any substances that had a pH that would cause tadpoles & fish to die.