Development of the Beckman pH Meter Mark as Favorite (0 Favorites)

LESSON PLAN in Acid & Base Theories, pH, Acids & Bases, ACS National Historic Chemical Landmarks Program. Last updated September 18, 2025.

Summary

In this lesson, students will learn about the development of Arnold Beckman’s pH meter, as well as related topics in the subject of acids and bases through reading an article and engaging in related activities. The activities help promote literacy in the science classroom. Parts of this lesson could be used as plans for a substitute teacher.

Grade Level

High School

NGSS Alignment

This lesson will help prepare your students to meet the performance expectations in the following standards:

  • HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
  • HS-ETS1-2: Design a solution to a complex real-world problem by breaking it down into small, more manageable problems that can be solved through engineering.
  • Scientific and Engineering Practices:
    • Using Mathematics and Computational Thinking
    • Analyzing and Interpreting Data
    • Constructing Explanations and Designing Solutions
    • Engaging in Argument from Evidence

    Objectives

    By the end of this lesson, students should be able to:

    • Describe the major milestones in the development of the pH meter.
    • State and explain different ways to measure acidity.
    • Define the term “pH” and explain how to calculate pH values.
    • Identify and describe different substances as acids or bases and determine their pH value.

    Chemistry Topics

    This lesson supports students’ understanding of:

    • Acids and Bases
    • The pH scale
    • pH and pOH Calculations

    Time

    Teacher Preparation: 10 minutes

    Lesson: Approximate times for students to complete each activity in the lesson:

    • Anticipation Guide: 10 minutes
    • Reading: 20 minutes
    • Timeline: 10 minutes
    • 3-2-1-Contact Graphic Organizer: 10 minutes
    • pH and pOH Calculations: 15 minutes
    • Evaluating pH: 20 minutes
    • Writing Prompt: 15 minutes

    Materials

    • Reading document and desired handouts to accompany the reading.
    • Internet (for possible research)

    Safety

    • No specific safety precautions need to be observed for this activity.

    Teacher Notes

    Background:

    Lesson Overview:

    The lesson includes the multiple components, as outlined individually below. The Reading is essential for all of the activities. Teachers can choose to do one or all of the included activities. Student handouts and corresponding answer keys are provided for each item described below:

    • Activity: Anticipation Guide
      • Students identify whether they agree or disagree with the ten statements. After they complete the reading, they can adjust their answers and rephrase the “disagree” statements, so they read true.
    • Reading: Development of the Beckman pH Meter
    • Activity: Timeline
      • During or after the reading, rearrange the statements in chronological order.
    • Activity: 3-2-1-Contact Graphic Organizer
      • Students complete the graphic organizer using evidence from the reading. They will then apply the information they learned in the reading.
    • Activity: pH and pOH Calculations
      • Using their calculators, students will perform basic calculations to determine the pH of certain household substances.
    • Activity: Evaluating pH
      • Students examine a short list of familiar substances and household products. They arrange the items in order of pH from 0 through 14. If needed, they may use the internet to support their decisions.
    • Activity: Writing Prompt
      • Students respond to a prompt to write a sales pitch for the Beckman pH Meter using the information they read in the article.