Date: Fri Aug 14 12:47:56 2009 Back to Contents ------------------------------------------------------------------------

Author: Dick Heckathorn

Subject: Re: FW: Why can't we see really small things?

Post:

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Greetings,



Thanks for the memories. I can vouch that it
worked.



Dick



From: tap-l-owner@lists.ncsu.edu
[mailto:tap-l-owner@lists.ncsu.edu] On Behalf Of
J. Terrence Klopcic
Sent: Friday, August 14, 2009 8:27 AM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] FW: Why can't we see really
small things?



Dick,

That phenomenon/technique has been applied for
years in the military. For night convoys,
military vehicles are (were? - I might be dating
myself pretty badly here) equipped with two sets
of small red lights on the back. Each set had
three lights: the outside one was farther from the
middle one than the inside one. Thus, the driver
of the vehicle behind could tell how closely
he/she was following. See one light: too far
behind. See three lights: too close.

Terry

J. Terrence Klopcic, PhD
Director of Laboratories
Departments of Physics and
Mathematics
Kenyon College



Dick Heckathorn wrote:

Greetings,



Stand looking down the road, (flat surface) and
focus on a car coming towards you. At first you
see only one light, then you see two lights when
it gets to a certain location. Then as it gets
closer, one sees 4 separate lights. One could use
the odometer to note the location when one first
see two lights and then 4. Knowing the distance
between the double lights and then the individual
lights could be investigated.



Can you repeat with a smaller car that has
different separation of lights.



Could one change the diameter of the lights.
(Maybe one could use carts by varying diameter of
the lights, and distance apart.



Could one have both approach at the same speed,
side by side.



Another factor as to when separation occurs
depends on the size of the opening of the viewer's
eyes. Not sure how to investigate this but one
might look through slits of various diameter
openings to see what happens. Have viewers with
different slit openings as the car approaches.



A third factor is the wavelength of the light.
(Different colors)



Now what have I overlooked.



Best wishes Dick












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Greetings,



Thanks for the memories. I can vouch that it = worked.



Dick



*From:* tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu]
*On Behalf Of *J. Terrence = Klopcic
*Sent:* Friday, August 14, 2009 8:27 AM
*To:* tap-l@lists.ncsu.edu
*Subject:* Re: [tap-l] FW: Why can't we see really small = things?



Dick,

That phenomenon/technique has been applied for years in the = military.
For night convoys, military vehicles are (were? - I might be dating
myself = pretty badly here) equipped with two sets of small red lights
on the = back. Each set had three lights: the outside one was farther
from the middle one = than the inside one. Thus, the driver of the
vehicle behind could tell how = closely he/she was following. See one
light: too far behind. See = three lights: too close.

Terry

* J. Terrence Klopcic, PhD
Director of Laboratories
Departments of Physics and Mathematics
Kenyon College*



Dick Heckathorn wrote:

Greetings,



Stand looking down the road, (flat surface) and focus on = a car coming
towards you. At first you see only one light, then you see two = lights
when it gets to a certain location. Then as it gets closer, one sees 4 =
separate lights. One could use the odometer to note the location when
one first = see two lights and then 4. Knowing the distance between the
double lights and = then the individual lights could be investigated.



Can you repeat with a smaller car that has different = separation of lights.



Could one change the diameter of the lights. (Maybe one = could use
carts by varying diameter of the lights, and distance = apart.



Could one have both approach at the same speed, side by = side.



Another factor as to when separation occurs depends on = the size of the
opening of the viewer?s eyes. Not sure how to investigate = this but one
might look through slits of various diameter openings to see what =
happens. Have viewers with different slit openings as the car = approaches.



A third factor is the wavelength of the light. (Different = colors)



Now what have I overlooked.



Best wishes Dick











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