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Author Topic: Shadow length  (Read 2380 times)

Offline Avadir

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Shadow length
« on: 16/12/2007 03:09:06 »
My friend and I, were standing near a light pole the other night. I went inside to get something and when i came back my friend told me that my shadow had increased length wise as I walked away from the pole. I said "Nonsense" and we put it to test. He was right. When I was near the pole, my shadow equaled my height, as I moved forward, it got longer and longer and longer.

We argued for a while and than we finally agreed that the reason what happened was happening was because when you are further from the origin place of light, the light doesn't get a chance to shed light on the umm area around you, because you are blocking it. I know it was a bootleg explaination but it made sense to us.. at that time.

I was wondering if someone could explain the whole thing, in less complex way.

P.S: The lack of sense, I don't speak the Queen's language that well.


 

paul.fr

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Shadow length
« Reply #1 on: 16/12/2007 03:27:07 »
P.S: The lack of sense, I don't speak the Queen's language that well.

not a problem, neither do we! and welcome to the forum.

If you imagine that the light on top of the pole is the sun, and you were standing still, as the sun got lower throughout the day then the length of your shadow would increase. If you were directly below the sun (light) then you would have zero shadow, to start with.

So what you were doing was sort of the opposite, you were moving away from a stationary sun, as such your shadow length got longer.

Shadows can be used to measure the height of buildings and other such things. If the sun was at a 45 degree angle to you and we measured the lenth of your shadow we would be able to tell your height. A man who is 6 foot tall, and the sun was at an altitude of 45 degrees, this would cast a 6 foot shadow...

if i am wrong, someone will correct.
« Last Edit: 16/12/2007 14:05:11 by paul.fr »
 

lyner

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Shadow length
« Reply #2 on: 19/12/2007 12:44:10 »

This is you at position 1 and position 2. The light goes in straight lines. - the triangles on the (left) side of the bodies show where the light is blocked by the body.
In position 1, you don't block as much as in position 2  so the shadow is shorter. Virtually no shadow when the lamp is directly overhead.
 

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Shadow length
« Reply #2 on: 19/12/2007 12:44:10 »

 

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