Episode 10: Color
| Friday 15 Feb 2008 |
Color literally fills our world, and it plays a dominant role in how we perceive our surroundings. Scientists have been fascinated with the question of what color is ever since Isaac Newton discovered that white light contains the entire color spectrum. Our show on color explains not only how color is produced, but also looks at how scientists use color to investigate the natural world. Join CHF’s Erin McLeary and Integral Molecular‘s Joe Rucker as they whip up a batch of mauvine, the first synthetic dye, in CHF’s catering kitchen. (You can see their results in the glove pictured above.) In this week’s Chemistry in Your Cupboard, learn how you can make your own pH meter with a common vegetable. Element of the Week: Chromium.
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Show Clock
00:00 Opening Credits
00:32 Introduction
01:09 Element of the Week: Chromium
02:54 Chemistry in Your Cupboard
05:12 Making Mauvine
10:47 Quote: Claude Monet
11:06 Closing Credits
Resources and References
On chromium: Web Elements Perioidic Table and this helpful Wikipedia entry
For a good explanation of the red cabbage phenomenon: a lecture demonstration from the University of Minnesota
On mauvine: Simon Garfield, “One Man and His Color: Reflections on Mauve’s 150th Birthday,” Chemical Heritage 24, no. 3 (Fall 2006), 8–10, 35.
On color in general: Philip Ball, Bright Earth: Art and the Invention of Color (New York, 2001).
Quotation: Claude Monet, as quoted J. Claretie, La Vie á Paris, 1881 (Paris, 1881), p. 26.
Credits
Special thanks to Hilary Domush for researching the show.
Our theme music is composed by Dave Kaufman. Additional music was provided from the Podsafe Music Network. The music for introduction to the Element of the Week is Sage Hill Theme, by Intelect. At the end of the Element of the Week the music is Boom Boom Beckett’s In a Sentimental Mood. The music at the end of Chemistry in Your Cupboard is Dog Day Afternoon, by Freddie Wong. Both the intro and the outro for mauvine segment is Rio Colorado, by Moth to a Candle.
This week’s photo was taken by Gregory Tobias.
Posted in Society
Great show, especially the part about mauvine. I wasn’t sure how much I would learn from an audio-only presentation on color, but I felt like I was right there in the kitchen watching the experiment.
A few questions — how long did it take for the dye to turn the shade of purple shown on the glove in the photo? Does liquid mauvine get darker and darker if you let it sit for a long time, or does it stabilize at a particular point? And do mauvine-dyed items keep their color for decades, or do they eventually fade? Thanks!
This white cotton glove was our second attempt at using our mauveine (the first, a silk scarf, only turned a light pink). Initially, the glove was a dark, rich purple. Then it sat around in my office. My very sunny office. Within just a few days, the dye had faded to the light purple you see here. But while our mauveine clearly wasn’t lightfast, there are historical samples of fabric dyed with mauveine that are still a brilliant purple. Here at CHF, we have some lovely samples, including ones over a hundred years old which are tipped into books (and thus have been in the dark for most of their existence). But one of my favorite historic mauveine samples is held by the Science Museum of London – you can see a picture at http://tinyurl.com/34gf8d.
I’ll have to ask Joe Rucker to weigh in on your other questions!
First things first.
The mauveine prep that we used was from Caveman Chemistry, a rather amusing chemistry text by Kevin M. Dunn, a faculty member at Hampden-Sydney College in Virginia. His website is http://www.cavemanchemistry.com.
When we made the mauveine, it started as a dark brownish color, which quickly became a very dark violet. If we had waited about an hour, it would have lightened somewhat to purple. We actually dyed the glove at the dark violet stage. The color of the glove slowly lightened over time.
The light pink scarf mentioned above was from a batch of mauveine I had made up the night before (in my own kitchen). The bleach I used was old and so the reaction probably didn’t go to completion. If you’re going to do this as a demonstration, make sure to use fresh bleach.
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