I sometimes think that we should spend at least a little time explaining everyday manifestations of physics to undergraduates, so that they can talk about phenomena that appear in everyday lives. How The Ray Gun Got Its Zap (2013), is subtitled Odd Excursions Into Optics, which (combined with the manifesto above) pretty much covers what … Continue reading Stephen R. Wilk: How The Ray Gun Got Its Zap
Tag Archives: Optics
Signalling Mirrors
I found this object a couple of months ago, prominently poised on a rock in the broken ground above the big bulldozed path on Beinn Bhuidhe. (Yes, I do occasionally climb a hill without telling you about it.) It was marked with rainwater and bird droppings, but cleaned up remarkably well once I got it … Continue reading Signalling Mirrors
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Perspective Tricks
Okay, one last time. These are small, but the ones out there are far away. Father Ted, “Hell” (1996) Graham Linehan, Arthur Mathews I was recently reminded of Father Ted explaining perspective to Father Dougal (is it really more than twenty years ago?) when I happened on a bit of art under the Tay Road … Continue reading Perspective Tricks
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Sun Dogs
Ever since the success of her Clatto Swan photograph, The Boon Companion has been intermittently getting out of her warm bed at some truly God-forsaken hours to photograph sunrises. She recently took some early morning photos on the beach at Saint Andrews. She’ll be a bit annoyed with me for having chosen a glary one … Continue reading Sun Dogs
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Reflections In A Spiral Mirror
The title of this post looks like it could be the name of a concept album by a pretentious prog-rock band. But it’s completely literal—I came across the spiral mirror in question while walking back from Tralee into Benderloch the other day. It was an outdoor ornament of the kind that seems to be called … Continue reading Reflections In A Spiral Mirror
Green Flash
Have you ever seen the sun set at the seaside? Yes? And did you follow it until the top edge of the sun’s disc just touched the horizon and then started to disappear? Probably. But did you observe the phenomenon that occurs at the instant of the last ray of light when the sky is … Continue reading Green Flash
Shape Of The Low Sun
Most people know why the sun looks orange-yellow when it’s rising or setting. Air preferentially scatters shorter (bluer) wavelengths of light—so the more air there is between your eye and the sun, the more short wavelengths are scattered out of the line of sight, leaving yellow/orange/red as the predominant colours reaching your eye. There’s about … Continue reading Shape Of The Low Sun
Why Do Veins Look Blue?
The blue appearance of veins under unpigmented skin is a commonplace observation, to the extent that it has become standard coding in anatomy diagrams to colour arteries red and veins blue: But that pale blue colour is actually a bit of a puzzle. Blood gets its colour from the haemoglobin contained in the red blood … Continue reading Why Do Veins Look Blue?
Nacreous
ˈneɪkriːəs nacreous: pertaining to or resembling mother-of-pearl Nacreous clouds are in the UK news at present, with multiple sightings in Scotland. There was an interesting divide in the BBC news coverage of the phenomenon this evening, with national newsreader George Alagiah intoning some twaddle about “forming at sunset” and “caused by refraction” in a sing-song … Continue reading Nacreous
Crepuscular Rays
Crepuscular rays are rays that occur during the crepuscule, which is a fine old word for “twilight”. They’re the rays of brightness and shadow that seem to fan outwards and upwards from the setting or rising sun when it is masked by cloud. What’s happening is that the shadow of the clouds is being projected … Continue reading Crepuscular Rays