Where does this come from, and can I check it?

Fluorescent materials absorb short wavelengths and re-emit them almost at once. The figure is taken from American Chemical Society, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a science fact?

Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Fluorescent things glow only while lit

Fluorescent materials absorb short wavelengths and re-emit them almost at once An absorbed photon lifts an electron to a higher energy level. When it drops back, it releases a photon of slightly lower energy, which means a longer wavelength. Because the delay is only nanoseconds, the glow stops as soon as the light source is removed, unlike phosphorescence. It sits in Mondo's science collection, one of 200 facts that each trace back to the reference below.

Where this comes from

American Chemical Society

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Science trivia

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Light travels at nearly three hundred million metres per secondIn a vacuum light travels at an exact speed of 299,792,458 metres per second Particles moving faster than light in water glow bright blueCherenkov radiation acts as an optical sonic boom for high speed charged particles Bioluminescence generates light without losing energy to heatEnzymatic oxidation of luciferin produces efficient cold light in living organisms Newton split white light with a prismA glass prism spreads sunlight into a rainbow because each colour bends differently A rainbow forms opposite the SunSunlight bends and reflects inside raindrops to make an arc around the antisolar point Rayleigh scattering makes the daytime sky blueAir molecules scatter short blue wavelengths far more strongly than long red ones

Tags: light, colour, materials

Fluorescent things glow only while lit: the short answers

Where does this come from, and can I check it?: Fluorescent materials absorb short wavelengths and re-emit them almost at once. The figure is taken from American Chemical Society, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a science fact?: Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.