Date: Thu, 16 Dec 2010 22:33:11

Author: Kenn Lonnquist

Subject: Re: Violet laser pointers and stimulated emission

Post:

--0016e6d77fa8c9177b0497948239
Content-Type: text/plain; charset=ISO-8859-1

It should be local heating; you can do the same with a red laser pointer (or
any bright light with less energy then blue light). It is particularly cool
to use an IR laser pointer, or an IR led light to heat the glowing paper;
you can see the paper get bright as you force the paper to give up it's
energy, then it goes dark. Friction will heat the surface enough too, but
an IR laser pointer is a step up on the coolness scale.

Similarly, cooling the paper will cause the paper to get darker, and there
is less thermal energy allowing the molecules to de-excite. You can do this
with a piece of ice, but you can also take it a step further. If you cool
most glow in the dark papers in LN2, they will stop glowing, and will
fluoresce instead. The phosphorescent energy loss mode becomes unavailable,
and so the paper actually stores energy. Then, when you warm the paper up,
the molecules can begin to phosphoresce, and the paper will light up again.
if kept chilled, the paper will hold onto it's stored energy for hours, if
not longer.

Kenn

On Thu, Dec 16, 2010 at 7:02 PM, William Beaty wrote:

> On Thu, 16 Dec 2010, Marc "Zeke" Kossover wrote:
>
> I figure that this is caused by simulated emission. Thoughts?
>>
>
> It might be from local heating. Does red light work the same? Try placing
> your hand on the surface for a few seconds. The higher temperature leaves a
> bright handprint. Lots of physics demo possibilities there.
>
>
>
>
>
> (((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
> William J. Beaty SCIENCE HOBBYIST website
> billb at amasci com http://amasci.com
> EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
> Seattle, WA 206-762-3818 unusual phenomena, tesla coils, weird sci
>



--
Kenneth Lonnquist
Assistant Coordinator, Introductory Physics Labs
KennLonnquist@gmail.com
970.491.2540
Physics Department
Colorado State University

--0016e6d77fa8c9177b0497948239
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

It should be local heating; you can do the same with a red laser pointer (o=
r any bright light with less energy then blue light).=A0 It is particularly=
cool to use an IR laser pointer, or an IR led light to heat the glowing pa=
per; you can see the paper get bright as you force the paper to give up it&=
#39;s energy, then it goes dark.=A0 Friction will heat the surface enough t=
oo, but an IR laser pointer is a step up on the coolness scale.

Similarly, cooling the paper will cause the paper to get darker, and th=
ere is less thermal energy allowing the molecules to de-excite.=A0 You can =
do this with a piece of ice, but you can also take it a step further.=A0 If=
you cool most glow in the dark papers in LN2, they will stop glowing, and =
will fluoresce instead.=A0 The phosphorescent energy loss mode becomes unav=
ailable, and so the paper actually stores energy.=A0 Then, when you warm th=
e paper up, the molecules can begin to phosphoresce, and the paper will lig=
ht up again.=A0 if kept chilled, the paper will hold onto it's stored e=
nergy for hours, if not longer.

KennOn Thu, Dec 16, 2010 at 7:02 PM,=
William Beaty llb@eskimo.com> wrote:

On Thu, 16 Dec 2010, Marc "Zeke" Kossover wrote=
:


I figure that this is caused by simulated emission. Thoughts?


It might be from local heating. =A0Does red light work the same? =A0Try pla=
cing your hand on the surface for a few seconds. =A0The higher temperature =
leaves a bright handprint. =A0Lots of physics demo possibilities there.





(((((((((((((((((( ( ( =A0( =A0 ( =A0 =A0(O) =A0 =A0) =A0 ) =A0) ) ))))))))=
)))))))))))
William J. Beaty =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0SCI=
ENCE HOBBYIST website
billb at amasci com =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http://amasci.com
EE/programmer/sci-exhibits =A0 amateur science, hobby projects, sci fair
Seattle, WA =A0206-762-3818 =A0 =A0unusual phenomena, tesla coils, weird sc=
i
-- Kenneth LonnquistAs=
sistant Coordinator, Introductory Physics LabsKennLonnquist@gmail.com970.491.2540Physics De=
partment

Colorado State University

--0016e6d77fa8c9177b0497948239--


Back