A fun science Experiment...

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trogdor

trogdor

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I was discussing the pros and cons of various pickup elements today at school with one of my old and eccentric professors when he told me of a little experiment he did using a solar panel as a kind of transducer...

First, he probably got pretty high. Then, he wired a little radio shack solar panel to a guitar (TS) cable and plugged it into a guitar amp.

He then cut the bottom off of a coffee can, and glued a thin mirror to the bottom with the reflective surface pointing out.

By pointing a laser at the mirror so that it reflected onto the solar panel, whilst talking into the other end of the can...his voice actually came out of the amp!! (quite distorted, but nonetheless..)

Q. How can longitudinal waves travel optically if nothing can go faster than light (and they have to pulse backwards and forwards while traveling in the same direction)

A. I think the mirror was creating fluctuations by diffracting the laser beam and thus varying how much current was inducted by the solar panel. Maybe not.

Q. What is this useful for?

A. Good question.

Anyway, I thought this was a pretty cool trick and wanted to share it with y'all...

trog
 
They use laser mics in surveilance work. By pointing a laser at a window they can eavesdrop into the room. I'm not sure how they pickup the reflected signal off the window.
 
Re: Re: Faster than light

bsanfordnyc said:
only on star trek
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I’m not a physicist but they are theoretical particles that move faster than the speed of light. Proving that they actually exist, that’s another story or Steven Hawking book! :cool:
 
TexRoadkill said:
They use laser mics in surveilance work. By pointing a laser at a window they can eavesdrop into the room. I'm not sure how they pickup the reflected signal off the window.
Click to expand...

...or how they keep the observees unaware of the little red dot floating around on the wall! :-)
 
We did this in college.

My college buddy was and electronics wiz (he was actually a totall genius ....perfect pitch, absolute timing, some sort of photografic mathmatical memory...and he did way too much acid)
But he had like 3 little weather lasers he stole from his high scool and I had this little light thing that you plug into your stereo and it makes squiggles on the wall in time with the bass notes.

Well he took a mirror and attached it to a fan at an angle....then took the photocell from the light box and like backwards wired it to to a boombox.

Then he bribed this kid down the hall to switch rooms with him because the kid lived dirctlly across from this girl in another wing of the dorm who the "genius" was dating.

Put a small piece of thin mylar on the outside of her window in the middle of the night.....and then we pointed the laser at the window, "caught" the reflection in the spinning mirror, and that hit the photocell attached to the boom box and we were able to listen to her (some of which got recorded....and she found out...and "genius" got in BIG trouble with the scool)

The sound was amazingly clear.

I dont know if the spinning mirror was neccessary but, hey, he was twisted genius.....I just opened the beers and packed the bong.

-mike
 
Did she say anything really interesting?

I feel dumb all of a sudden.
 
So they bounced it off the mylar on the window, muhahaha. Thanks FZ, I was wondering how they do that.
 
"Q. How can longitudinal waves travel optically if nothing can go faster than light (and they have to pulse backwards and forwards while traveling in the same direction)"

the vibrations induced by his voice would cause minute and rapid variations in the distance between the reflective surface and the photoreceptor. light would continue to travel at a constant speed but the differences in distance would create differences in the rate at which individual photons struck the photoreceptor directly related to the audible frequencies modulating the reflector. with that sort of input, the photoreceptor would function much like a class d amplifier.
 
Well...

she actually had some mojor drama going on.

She thought that the genius wasnt into the relationship so she was contemplating getting together with this other guy.....who lived in our dorm right down the hall.

She would always talk to her roomate/best friend about it.

So then the genius started playing head games with the other dude and with her to point where she figured out that he must be overhearing her somehow....

It was some good soap opera drama for a while.


Tex....the mylar isn't toally neccessary but it prevents the laser from showing on the wall inside the room and makes the reception much better.
It also helps when the windows basically suck because they vibrate more.

Playing with the angles of the laser in order to catch the reflection took a LOT of time and was a reel pain in the ass.

Aaaahhhhhhh those crazy college kids.......


-mike
 
trogdor said:
...or how they keep the observees unaware of the little red dot floating around on the wall! :-)
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Not all lasers are red. Some wavelengths are invisible.

Twist
 
twist said:
Not all lasers are red. Some wavelengths are invisible.

Twist
Click to expand...

Heh...That's true. But how would you aim it so precisely?
 
Re: Re: Re: Faster than light

Simman said:
I’m not a physicist but they are theoretical particles that move faster than the speed of light. Proving that they actually exist, that’s another story or Steven Hawking book! :cool:
Click to expand...


No, because as you look closer into Physics and particularly M-Theory or String theory the speed of light isn't necessarily a speed, but rather a 'gap' between p-branes, or dimensions if you will.

In other words, there is more to the speed of light than a non-mass object travelling through 3-dimensional space (ie, the traditional Photon or Neutrino).

Hawking *hints* on it in the universe in a Nutshell, but for a full explanation you need to read 'faster then the speed of light' by Joao Magueijo.

To cut a long story short, anything travelling at the speed of light isn't totally in our 3-dimensions. Anything faster would HAVE to exist outside of 3-dimensional space.

Therefore, Tachyons don't travel faster than the speed of light - they travel faster than light in that they travel through time, not space. This makes them appear to travel somewhere before they left and the illusion of faster than light.

This is all very very theoretical stuff though........
 
Re: Re: Re: Re: Faster than light

Neil Ogilvie said:
This is all very very theoretical stuff though........
Click to expand...

Good explanation nonetheless! I'll have to check those books out..
 
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