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The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 21 (2016) pp 36-39

The Effectiveness and Range of Natural Acid-Base Indicators

Maria Danielle Garrett*

Department of Chemistry and Physics, Belmont University, 1900 Belmont Boulevard, Nashville, Tennessee37212, danielle.garrett@belmont.edu
Received November 29, 2015. Accepted January 5, 2016.

Published: 22 January 2016

Abstract. Concerns for student safety, limited access to a variety of chemicals and lab equipment, access to chemical disposal services, and disposal budgets can often be severely limiting factors in creating an environment of hands-on learning in the science classroom. Access to practical, environmentally friendly, low-budget labs that can address multiple curriculum standards provide science teachers with the opportunity to incorporate more lab-based explorations into their lessons. This laboratory exercise, exploring the effectiveness and pH range of foods as natural acid-base indicators, was developed for use in middle and high school science classes. This exercise has a broad range of applications and could be used in studies involving the properties of matter, pH and titrations. Functional indicator color-scales were generated for anthocyanin (in red cabbage, blueberries, red apple peels and cranberries), curcumin (in turmeric) and betanin (in beets). Each indicator was tested on a series of ten solutions (2.30 < pH < 10.50). Detailed instructions regarding experimental preparation for the instructor and both instructor and student versions of pre-lab questions, data analysis and post-lab questions have been included as supporting information.

Key Words: Laboratories and Demonstrations; general chemistry; high school chemistry; physical science; middle school science; hands-on learning; acids/bases; green chemistry; natural indicators; edible indicators; pH; anthocyanin; betanin; curcumin

(*) Corresponding author. (E-mail: danielle.garrett@belmont.edu)

Article in PDF format (1.48 MB) HTML format

Supporting Materials:

Detailed instructions regarding experimental preparation for the instructor and both instructor and student versions of pre-lab questions, data analysis and post-lab questions. (975 KB)

 



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