Skip to main content
 

Sponges and Bubbles

A Refreshed Investigation of pH and Buffers

By Geoffrey M. Lippa, Heather Zimbler-DeLorenzo, Jean A. Cardinale

Sponges and Bubbles


 

Abstract

This directed case study with laboratory components is an adaptation of a “clicker case” by Terry Platt that reviews basic chemistry to explain pH and buffers (see “Acids, pH and Buffers: Some Basic Chemistry for Biological Science” published by the National Center for Case Study Teaching in Science). This adaption shares the same storyline as the original, but also includes two experiments to be completed in class that explore the ways in which the properties of a standard kitchen sponge can be used to understand the important function of buffer systems in the regulation of pH. The case is presented in class using PowerPoint slides and supporting documents, shared either electronically or in print (see Supplemental Materials). The case is ideally suited for an introductory biological or biochemical lecture or laboratory class.

   

Date Posted

12/06/2021

Overview

Objectives

• Define the terms acid, base, and buffer.
• Explain the relationship between acids or bases and the pH of a solution.
• Use the analogy of a common household sponge to describe the action of buffers to bind or release protons, including the physical limitations of a buffering system.
• Describe the equilibrium between carbon dioxide and bicarbonate ions and explain how this equilibrium can be used by the body to regulate blood pH.
• Describe how changes in breathing rate influence blood pH.

Keywords

Buffer; pH; acid; base, dissociation constant; equilibria; equilibrium; bicarbonate; carbonic acid; pH indicator; acidosis;

  

Subject Headings

Biochemistry
Biology (General)
Chemistry (General)
Medicinal Chemistry
Medicine (General)
Nursing
Pharmacy / Pharmacology
Physiology
Public Health
Science (General)

EDUCATIONAL LEVEL

High school, Undergraduate lower division

  

FORMAT

PDF, PowerPoint, Word

   

TOPICAL AREAS

N/A

   

LANGUAGE

English

   

TYPE/METHODS

Directed, Discussion, Laboratory

 

 

Asset 2