The Day Lengthening Mystery: an explanation.

Andy in Sig

Vice President in Exile
I mentioned a few weeks back that it was odd that the evenings were getting longer and the mornings barely budging. I am now in a postion to provide the answer.

Some years ago a schoolboy howler of an exam answer was reported in the papers. The question demanded an explanation of why days were longer in summer and shorter in winter and the kid wrote: "When things get hot they expand and when they get cold they contract."

Like everbody else I laughed at this but ... the kid must have been right! The nights are cold and it takes a bit for the sun to warm things up and so the mornings are not expanding (i.e. getting earlier) as quickly as the evenings are getting later when the day is cooling down and so contracting. Problem solved. Forget all this nonsense about orbits and precession.

Keith Oates

Penarth, Wales
Phew, glad that's sorted!!!!!!!!!!!!!!!!!!!!!!!!!!!!


I'm told that this is an actual answer to a physics exam question.

A. When a gas heats up, the molecules move faster. As their speed increases, their mass increases in accordance with the Special Theory of Relativity. The mass of the molecules increases, therefore the density increases, therefore the hot air rises.

Don't ask...


Über Member




School ain't what it was when I were a lad. I got "SEE ME"'d for things like smudging a diagram, giving the wrong answer, homework late, that sort of cr@p....

Smokin Joe

Legendary Member
But did Dom get his dick sucked when he did see him?her?


New Member
Andy that temperature explanation is a load of rubbish. The correct explanation is a biological one. In the morning, people are tired and it takes a while for their eyes to open properly. It is getting lighter at the same rate as the evenings are, but people aren't perceiving it to be because their optic envelope isn't fully dilated. As sunset approaches, we all wander around like bushbabies and so every possible kilo* of light is hoovered into the eye socket and onto the retina.

If there's anything else that's eating away at you then let me know; but first think about it in biological terms and I think you'll find an answer presents itself more often than not.

*correct unit of measurement for light.


Morrisette said:
Oh those exam answers are so funny :biggrin:
The questions are good fun too! I can't make much out of the 'kittens' one, not my line! - but the one to which our intrepid pupil replied "because he slept with his boss's wife" appears to read like this:
The water of the earth's oceans stores lots of heat. An engineer designed an ocean liner that would extract heat from the ocean's waters at Th=10C (283K) and reject heat to the atmosphere at Tl=20C (293K). He though he had a good idea, but his boss fired him. Explain.

My answer would be, that he left Engineering and took up a career as a famous artist, producing stuff like this...

Now, how about turning this into a "Second Law of Thermodynamics" thread then? xx(
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