Designing a Color-Changing Paint Using pH
The pH Scale: Which products in your home are acidic, neutral, or alkaline?Copyright 2017 Enviromental Protection Agency, Public Domain, EPA.gov https://www.epa.gov/acidrain/what-acid-rain
How can an understanding of pH—a logarithmic scale used to identify the acidity or basicity of a water-based solution—be used to design and create a color-changing paint? This activity provides students the opportunity to extract dyes from natural products and test dyes for acids or bases as teams develop a prototype “paint” that is eventually applied to help with a wall redesign at a local children’s hospital. Students learn about how dyes are extracted from organic material and use the engineering design process to test dyes using a variety of indicators to achieve the right color for their prototype. Students iterate on their dyes and use ratios and proportions to calculate the amount of dye needed to successfully complete their painting project.
Knowledge and understanding of pH is crucial in many aspects of engineering. In pH testing, engineers can understand acids and bases and their impact on many practices that are used in industry, research and development, and in consumer products. Effective use of pH testing has a measurable impact across many engineering fields, particularly in biological and chemical engineering and is an essential component in research and engineering design.
After this activity, students should be able to:
- Safely extract dye from organic material using water.
- Accurately test pH of various substances.
- Determine if a substance is acidic or basic.
- Discuss how substances change color in the presence of application of indicators.
- Determine proportional relationships.
- Use proportional relationships to determine scaled quantities.
- Create a multimedia component and include it in a presentation that clarifies findings and emphasizes salient points.