National Chemistry Week: Molecules, Light and Natural Dyes

[ACSGCI]

This year the American Chemical Society and chemists around the world are celebrating National Chemistry Week (NCW) in color! The 2015 NCW theme is "Chemistry Colors Our World", focusing on the chemistry of food colors, fireworks, rainbows, natural dyes, pigments, and more.

The University of California Berkeley has the perfect green chemistry lab experiment students can perform during this week of chemistry celebration involving natural dye molecules.

Light Inquiry: Molecules, Light, and Natural Dyes

Research Questions:

What procedure would be suitable for extracting β-carotene from carrots?  How can you determine how much β-carotene was extracted?

Learning Goals:

In this lab, you will design an experiment to extract β-carotene from carrots and determine the concentration of the resulting solution using visible spectroscopy and Beer’s Law. You will examine how changes in sample concentrations result in changes in absorbance and transmission. You will also be using a spectroscope to explore the interactions of light and matter.  This will help you to understand light, transmission, reflectance and absorbance on a more qualitative level using your own eyes as the detector.  This lab introduces you to spectroscopy and extraction. The solvents used are non-toxic making them Inherently Safer and allowing us to conduct the extraction using Safer Solvents. Additionally, the extracted β-carotene comes from Renewable Feedstocks.

See the attached documents for the lab activity and activity with teacher’s notes.

Take a picture of yourself and peers conducting this experiment during NCW and tweet @ACSGCI using #greenchemistry and #NationalChemistryWeek!

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