Tag Archives: spectrum

Experiments, Fun, Physics

Want a Full Spectrum Love Life? Watch This CD

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It’s that candlelit dinner stage of the evening.   Soup through nuts, you’ve been your wonderful, genuine, self.  And he/she is pretty fantastic too.

spectrum of candle flame by diffraction from CD
Spectrum of candle flame by diffraction in a CD (Photo:Tim Jones)

But why take chances – this is deal clinching time.

With the table cleared, quick as a whippet you pull out your Ethereal Collapse CD, and with a flourish Newton would die for if he wasn’t already dead, guide your beloved’s eye to the spectacular demonstration of spectra by diffraction.

Your friend will by now be in a frenzy of excitement, so this is the moment to push them over the edge.

Rushing through to the restaurant kitchen with a mix of urgency and discord normally reserved for Bond movies, you thrust your CD into the light once again.  But now the disc reflects the chef’s fluorescent tube in an almost unbearably different, and extremely interesting way.  The smooth continuum of the candle flame is gone!  Now superposition bands stand proud, where line discharge spectra from gaseous mercury inside the lamp combine with the continuous spectra emitted from the phosphor coating.

Spectrum of fluorescent lamp by diffraction in a CD (Photo: Tim Jones)
Spectrum of fluorescent lamp by diffraction in a CD (Photo: Tim Jones)

At this point, you’ll almost certainly be offered complimentary Cognacs – if only to leave the kitchen.   But by now you’ll both be itching to get off anyway, back to his/her flat to repeat the experiments under controlled conditions.  Or maybe play some Scrabble.

Note: Humphry Davy was up for colour ploys (Link to ‘Humphry Davy – Finding Love in the Colourful Age of Romantic Science’)

Art, Books, History, Philosophy of Science

Unweaving the Rainbow

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I took this short sequence in the garden this afternoon.  No photo-shopping, just a nice illustration of the splitting of sunlight into it’s component colors by refraction through a water drop – shuddering in the breeze after a storm.

rainbowThe simplest of things, it put me in mind of John Keats’s supposed lament that Isaac Newton had destroyed the beauty of the rainbow by explaining the science behind it, the underlying sentiment of which he included in the poem Lamia.  I say supposed, because I can’t find a primary reference to Keats actually ‘having a go’ at Newton over his prism or whatever.  Lamia however speaks for itself (see below).

Rainbow over LondonRichard Dawkins gives an alternative view in his book, Unweaving the Rainbow, where he argues scientific understanding enhances rather than diminishes beauty.  I’m with Dawkins on this one.  And while those going through life without a scientific education (for whatever reason) experience it in a way that is different, I believe they are also simply missing out.

Keats’s rainbow reference appears in his poem Lamia Part II:

What wreath for Lamia? What for Lycius?
What for the sage, old Apollonius?
Upon her aching forehead be there hung
The leaves of willow and of adder’s tongue;
And for the youth, quick, let us strip for him
The thyrsus, that his watching eyes may swim
Into forgetfulness; and, for the sage,
Let spear-grass and the spiteful thistle wage
War on his temples. Do not all charms fly At the mere touch of cold philosophy?
There was an awful rainbow once in heaven:
We know her woof, her texture; she is given
In the dull catalogue of common things.
Philosophy will clip an Angel’s wings,
Conquer all mysteries by rule and line,
Empty the haunted air, and gnomed mine—
Unweave a rainbow, as it erewhile made
The tender-person’d Lamia melt into a shade.