John Naylor
@johncnaylor.bsky.social
Interested in the physics of sights and sounds in nature.
Author of “Out of the Blue, A 24-hour Skywatcher’s Guide”, “Now Hear This, A Book About Sound” & "The Riddle of the Rainbow"
Author of “Out of the Blue, A 24-hour Skywatcher’s Guide”, “Now Hear This, A Book About Sound” & "The Riddle of the Rainbow"
A good illustration of the progression of sun's rosy hue during a sunset. Clouds in the upper right are uncoloured because they are now within the earth's show and so no longer directly illuminated by the sun. As the sun drops further below horizon, the rosy moves west (towards right of image)
September 29, 2025 at 2:29 PM
A good illustration of the progression of sun's rosy hue during a sunset. Clouds in the upper right are uncoloured because they are now within the earth's show and so no longer directly illuminated by the sun. As the sun drops further below horizon, the rosy moves west (towards right of image)
Sunshine & showers are the sine qua non of rainbows. But always bear in mind, a rainbow only exists if it is seen. This bright rainbow exhibiting many of the classic features was visible for several minutes from a street near my home a couple of days ago. An endlessly fascinating phenomenon!
September 15, 2025 at 11:06 AM
Sunshine & showers are the sine qua non of rainbows. But always bear in mind, a rainbow only exists if it is seen. This bright rainbow exhibiting many of the classic features was visible for several minutes from a street near my home a couple of days ago. An endlessly fascinating phenomenon!
This curious pattern is due to convection in fruit puree.
August 10, 2025 at 11:11 AM
This curious pattern is due to convection in fruit puree.
Runge & Goethe corresponded on the subject of coloured shadows, a phenomenon first described by da Vinci tinyurl.com/25b49db9 & correctly explained by G. Monge (1789). Descriptions on how to produce such shadows by Goethe tinyurl.com/476pbny6 & Rumford tinyurl.com/43w5vzj9. My flashlight version
July 24, 2025 at 10:56 AM
Runge & Goethe corresponded on the subject of coloured shadows, a phenomenon first described by da Vinci tinyurl.com/25b49db9 & correctly explained by G. Monge (1789). Descriptions on how to produce such shadows by Goethe tinyurl.com/476pbny6 & Rumford tinyurl.com/43w5vzj9. My flashlight version
Here is its audio spectrum
July 17, 2025 at 4:40 PM
Here is its audio spectrum
As an aficionado of sources of unusual sounds, I commend your wife’s ambition! My shop bought TT produces a large number of closely spaced harmonics, which one would not guess from its raucous sound. My T.T., 18cm long, is loudest at ~450Hz.
July 17, 2025 at 4:37 PM
As an aficionado of sources of unusual sounds, I commend your wife’s ambition! My shop bought TT produces a large number of closely spaced harmonics, which one would not guess from its raucous sound. My T.T., 18cm long, is loudest at ~450Hz.
Dave’s image gives the lie to the common claim that a sunpillar is due to sunlight reflected by a vertical column of ice crystals. Here clouds stretch almost to the horizon, and are closer to the eye than the sun, which would block the vertical column of crystals. This very evident in my photo.
June 29, 2025 at 2:53 PM
Dave’s image gives the lie to the common claim that a sunpillar is due to sunlight reflected by a vertical column of ice crystals. Here clouds stretch almost to the horizon, and are closer to the eye than the sun, which would block the vertical column of crystals. This very evident in my photo.
Parhelia are formed when sunlight passes through a cloud of hexagonal plate ice crystals. If the cloud is sufficiently extensive (say 60°) and centred on the sun, there may be parhelia ~25° either side of sun. Quite common though really bright ones are rare in my experience.
June 16, 2025 at 4:47 PM
Parhelia are formed when sunlight passes through a cloud of hexagonal plate ice crystals. If the cloud is sufficiently extensive (say 60°) and centred on the sun, there may be parhelia ~25° either side of sun. Quite common though really bright ones are rare in my experience.
Eye catching! Reflections in rippled water are amenable to the laws of reflection as you will learn from tinyurl.com/4zewy2j7 . As the diagram shows, the surface of rippled water provides several reflections of any given point on an object seen from the far side of a body of water.
June 16, 2025 at 4:13 PM
Eye catching! Reflections in rippled water are amenable to the laws of reflection as you will learn from tinyurl.com/4zewy2j7 . As the diagram shows, the surface of rippled water provides several reflections of any given point on an object seen from the far side of a body of water.
This is the optical equivalent of an anechoic chamber. Most instructive! Tempted to buy a small pot of Musou Black to experience the effect it has on obliterating surface features.
June 11, 2025 at 4:11 PM
This is the optical equivalent of an anechoic chamber. Most instructive! Tempted to buy a small pot of Musou Black to experience the effect it has on obliterating surface features.
A whispering wall behind Tate Modern; just across the river from the most famous, though by no means the only, whispering gallery in the world at the base of the dome of St.Paul’s. Had the wall been made taller and a shelf added on which one could sit, the Tate would have another "installation"
May 23, 2025 at 10:20 AM
A whispering wall behind Tate Modern; just across the river from the most famous, though by no means the only, whispering gallery in the world at the base of the dome of St.Paul’s. Had the wall been made taller and a shelf added on which one could sit, the Tate would have another "installation"
If you are interested in the science of sound & hearing, “Now Hear This, A Book About Sound” is a wide-ranging exploration of the nature of sound and hearing Employing a combination of physics, biology, philosophy, literature, history, anecdote and personal experience.
May 18, 2025 at 12:15 PM
If you are interested in the science of sound & hearing, “Now Hear This, A Book About Sound” is a wide-ranging exploration of the nature of sound and hearing Employing a combination of physics, biology, philosophy, literature, history, anecdote and personal experience.
The sound of the eruption was heard 20mins later in Vancouver 330km away but not heard not heard within 100Km of Mt St Helens. A classic example of anomalous propagation of sound/zones of silence. See tinyurl.com/3v7u5zwh
pp 186-8
pp 186-8
May 18, 2025 at 12:11 PM
The sound of the eruption was heard 20mins later in Vancouver 330km away but not heard not heard within 100Km of Mt St Helens. A classic example of anomalous propagation of sound/zones of silence. See tinyurl.com/3v7u5zwh
pp 186-8
pp 186-8
The awful sound of wheel squeal is nevertheless composed of harmonics as shown by this audiogram I recorded while travelling in the underground a couple of years ago.
May 8, 2025 at 4:00 PM
The awful sound of wheel squeal is nevertheless composed of harmonics as shown by this audiogram I recorded while travelling in the underground a couple of years ago.
NOT a rainbow, just a serendipitous encounter with a spectrum…
April 25, 2025 at 3:43 PM
NOT a rainbow, just a serendipitous encounter with a spectrum…
Marcel Minnaert (1893-1970) was the author of the vade mecum of those of us fascinated by the optics of the atmosphere: "The Nature of Light and Colour in the Open Air". There are two further volumes on sound, heat and electricity unfortunately not translated.
April 21, 2025 at 4:48 PM
Marcel Minnaert (1893-1970) was the author of the vade mecum of those of us fascinated by the optics of the atmosphere: "The Nature of Light and Colour in the Open Air". There are two further volumes on sound, heat and electricity unfortunately not translated.
Have you ever used Minnaert's tricks to determine frequency of a sound when out and about without an audio spectrometer to hand? Christian Huygens used method 1 when he came across a musical echo in Chateau de Chantilly: tinyurl.com/33tbwjhm
April 21, 2025 at 4:45 PM
Have you ever used Minnaert's tricks to determine frequency of a sound when out and about without an audio spectrometer to hand? Christian Huygens used method 1 when he came across a musical echo in Chateau de Chantilly: tinyurl.com/33tbwjhm
The cause of sounds due to bubbles in water was discovered in 1933 by Marcel Minnaert: "On musical air-bubbles and the sound of running water", Philosophical Magazine, 16 (104): 235–248. Also in vol 2 of De natuurkunde van 't vrije veld.
April 21, 2025 at 4:43 PM
The cause of sounds due to bubbles in water was discovered in 1933 by Marcel Minnaert: "On musical air-bubbles and the sound of running water", Philosophical Magazine, 16 (104): 235–248. Also in vol 2 of De natuurkunde van 't vrije veld.
The allosonic effect is due to the fact that bubbles in a liquid make it more compressible, which in turn reduces the speed at which compression waves travel through it.
April 20, 2025 at 2:49 PM
The allosonic effect is due to the fact that bubbles in a liquid make it more compressible, which in turn reduces the speed at which compression waves travel through it.
A bit of physics to round off an enjoyable Easter Sunday meal of slow cooked lamb shoulder, ratatouille and broad beans & feta: a well-made espresso that exhibits the allasonic effect (aka hot chocolate effect)
April 20, 2025 at 2:47 PM
A bit of physics to round off an enjoyable Easter Sunday meal of slow cooked lamb shoulder, ratatouille and broad beans & feta: a well-made espresso that exhibits the allasonic effect (aka hot chocolate effect)
The celebrated phenomenon of coloured shadows. Incandescent light source to the left and skylight from the top of the image. Shadows are blue!
April 16, 2025 at 10:57 AM
The celebrated phenomenon of coloured shadows. Incandescent light source to the left and skylight from the top of the image. Shadows are blue!
Shadows and the odd tiny caustic cast by drops of water on a vertical surface illuminated by sunlight
April 16, 2025 at 10:53 AM
Shadows and the odd tiny caustic cast by drops of water on a vertical surface illuminated by sunlight
Shadow of nigella seed pod cast on tracing paper
April 16, 2025 at 10:35 AM
Shadow of nigella seed pod cast on tracing paper
Shadows on the bed of a stream
April 16, 2025 at 10:33 AM
Shadows on the bed of a stream
Shadows and caustics due to sunlight passing through old glass windows
April 16, 2025 at 10:32 AM
Shadows and caustics due to sunlight passing through old glass windows