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Chemistry In Pictures

Chemistry in Pictures: Unidentified fluorescent object

by Manny I. Fox Morone
August 12, 2021

A side-by-side comparison of the visible light and ultraviolet light appearance of a burnt model rocket engine made of clear plastic with soot visible on the inside; the ultraviolet light image shows the soot glowing whitish green.
Credit: Andres Tretiakov

This model rocket engine was an entirely clear acrylic tube when Andres Tretiakov first assembled it. But after ignition, the inside of the engine developed an opaque layer of soot as the acrylic—which functions as fuel in the rocket engine—burned up. Tretiakov, a physics technician at St. Paul’s School in London, flowed oxygen through the engine from the top, which causes the acrylic to oxidize once ignited. The reaction forms carbon dioxide and gaseous water, which exit from the bottom of the engine, generating thrust.

That all worked fine, but then upon shining a black light on the used engine, Tretiakov noticed that the soot glowed an eerie yellow green. He’s not quite sure what causes this glow but thinks it may mean that fluorescent carbon nanostructures formed in the soot. If you have thoughts on what causes the glow, reach out to @Andrestrujado on Twitter.

Submitted by Andres Tretiakov. Follow Andres on Twitter @Andrestrujado.

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This story was updated on Aug. 12, 2021, to correct the byline. The author is Manny I. Fox Morone, not Marsha-Ann Watson.


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