Teaching Acid–Base Fundamentals and Introducing pH Using Butterfly Pea Flower Tea

Abstract

Stimulating interest in science at an early age is important for STEM education. This work details an educational activity utilizing the anthocyanins found in butterfly pea flowers (Clitoria ternatea). This activity was developed for use in official classroom settings, online, and/or at-home with parental or educator guidance. Primary and high school students aged 7 to 14 performed a straightforward extraction of anthocyanin pH indicators from Clitoria ternatea with hot water. Students were able to use this indicator and its vast range of colors to compare the acidities and basicities of different household solutions. Most of the recorded responses show that students used reasoning from the indicator and a subsequent chemical reaction to correctly differentiate acids from bases and compare their strengths. Overall, this activity’s application of nontoxic and easily accessible indicators from the butterfly pea flower assisted in introducing young students to various concepts in acid–base chemistry, including acid/base strength and pH, solute dissolution, neutralization reactions, and qualitative analysis.