Featured in PASCO’s College Biology Instructor Guide

College Biology Instructor Guide

(PS-3800A)

College Instructor edition with 26 experiments covering introductory and general biology topics.

pH and Buffers

Lab Summary

Use a water quality sensor to measure the pH of buffers and the differences in pH values of various household products.

Theory

Biological systems are incredibly sensitive to the pH of their environments. In this lab, students discover the pH of some common household products and then learn how biological systems buffer large-scale changes in pH. In this activity, students:

  • Explore the effects of pH on the activity of an enzyme.
  • Understand that buffers minimize the effects of acids and bases.
  • Understand how acids and bases affect the functions of enzymes and the functions of proteins.

Method

Students gain experience conducting the following procedures:

  • Creating a buffer, and measuring the difference in the change of the pH in buffered and nonbuffered solutions.
  • Measuring and understanding pH values for household products.

Sensors / Equipment Used:

PASPORT Water Quality Sensor

(PS-2169)

Measures temperature, conductivity, pH/ISE/ORP and dissolved oxygen. It is specifically designed for convenience in conducting water quality lab experiments. For use with PASPORT Interfaces.

Materials Used:

0.1 M Hydrochloric acid (HCl) solution - 35 mL
0.1 M Sodium hydroxide (NaOH) solution - 35 mL
Beaker, 100-mL - 4
Beaker, 500-mL 
Beaker, 50-mL - 8
Disposable pipet 1 mL 
Distilled water - 1 L
Electronic Balance 
Gelatin solution - 150 mL
Graduated cylinder, 10-mL 
Graduated cylinder, 25-mL 
Graduated Cylinder, 50-mL 
Hot Plate
Labeling marker 
Labeling tape 
Meat tenderizer - 7 g
Paper towels 
Sodium acetate 2 g per class
Standard buffer (pH 10) - 25 mL
Standard buffer (pH 4) - 25 mL
Test tube rack
Test Tubes, 25 mm x 150 mm - 15
Various fruit juices, household ammonia, bleach and vinegar - 25 mL
Wash bottle with distilled water - 1 per class
Weighing paper - 14

The Associated Bundle:

College Biology Bundle

(PS-2926B)

A complete probeware bundle designed for PASCO's College Biology curriculum

Interface Required

This experiment may require software and an interface for data collection.