Volume 94 Issue 7 | p. 39
Issue Date: February 15, 2016

Chemistry in Pictures

Department: Science & Technology
Keywords: cenchempics, chemiluminescence, rainbow

Selections from cen.chempics.org, where C&EN showcases the beauty of chemistry

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RAINBOW IN A TEST TUBE
As a demonstration for her students, Lana Šaric, a chemistry teacher in Zagreb, Croatia, prepared these colorful tubes by dissolving various amounts of sugar in hot water and dyeing each a different color. The blue solution had the most sugar, followed by the green, then the yellow, and finally the red solution had the least. She then gently dripped the solutions into the test tubes. The kicker is, she got the same sequences of colors regardless of the order in which she added them. Each solution had a different density because of its sugar concentration, and solutions of different densities mix very slowly even if the solvent is the same. So the most dense solution flowed to the bottom of the tube, while the least dense stayed near the top.—Craig Bettenhausen
Credit: Submitted by Lana Šariç
A hand is held over a blue-glowing solution in a volumetric flask with a broken neck.
 
RAINBOW IN A TEST TUBE
As a demonstration for her students, Lana Šaric, a chemistry teacher in Zagreb, Croatia, prepared these colorful tubes by dissolving various amounts of sugar in hot water and dyeing each a different color. The blue solution had the most sugar, followed by the green, then the yellow, and finally the red solution had the least. She then gently dripped the solutions into the test tubes. The kicker is, she got the same sequences of colors regardless of the order in which she added them. Each solution had a different density because of its sugar concentration, and solutions of different densities mix very slowly even if the solvent is the same. So the most dense solution flowed to the bottom of the tube, while the least dense stayed near the top.—Craig Bettenhausen
Credit: Submitted by Lana Šariç
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‘BLOOD LAMP’
Mike Thompson, an artist based in Amsterdam, wanted to design a piece that forced people to think about the cost of the power they use. So he made a lamp lit with the user’s blood. His “Blood Lamp” glows thanks to a reaction with luminol, a molecule used in police forensics that gives off electric blue light when exposed to an iron-rich blood protein called hemoglobin. Iron atoms catalyze the oxidation of luminol, creating a high-energy, unstable peroxide molecule that releases energy as blue light as it relaxes to its lower-energy ground state. After the user adds blood and the reaction consumes all of the luminol, the light fades, and the lamp can never be used again.—Manny Morone
Credit: Mike Thompson
Seven test tubes filled with rainbow liquids.
 
‘BLOOD LAMP’
Mike Thompson, an artist based in Amsterdam, wanted to design a piece that forced people to think about the cost of the power they use. So he made a lamp lit with the user’s blood. His “Blood Lamp” glows thanks to a reaction with luminol, a molecule used in police forensics that gives off electric blue light when exposed to an iron-rich blood protein called hemoglobin. Iron atoms catalyze the oxidation of luminol, creating a high-energy, unstable peroxide molecule that releases energy as blue light as it relaxes to its lower-energy ground state. After the user adds blood and the reaction consumes all of the luminol, the light fades, and the lamp can never be used again.—Manny Morone
Credit: Mike Thompson

To enter our photo contest, visit cen.chempics.org or e-mail CENChemPics@acs.org.


 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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