What's the smallest thing that can be seen?
Discussion
Chris71 said:
P9 said:
Jonny671 said:
What about the atoms colliding in CERN? Thats quite small, I think you can see them on certain videos as white sparks..
That's the reaction, not the atoms themselves.I must admit I don't know exactly how they work, but wouldn't anything on an electron microscope be the same? You're seeing a representation of what the electrons bounce off/interactive with/whatever rather than an actual image.
Frankeh said:
The observer effect starts coming into play though. So what you're really looking at might have not been happening had you not looked at it.
Futurama:Speaker: "And the winner is ... Number 3, in a quantum finish."
Farnsworth: "No fair! You changed the outcome by measuring it!"
Doobs said:
Frankeh said:
The observer effect starts coming into play though. So what you're really looking at might have not been happening had you not looked at it.
Futurama:Speaker: "And the winner is ... Number 3, in a quantum finish."
Farnsworth: "No fair! You changed the outcome by measuring it!"
caz4213 said:
wavelength of (visible) light is between 400-700nm, so optically (if you could get a magnifier that big I'm not sure) the smallest object you could see would be around 400nm long. I think..
So, given atoms are typically 0.1 nm or so and a water molecule is something like 0.29 nm (according to some random website) we're talking about something that's already pretty huge in particle physics terms! 
Chris71 said:
caz4213 said:
wavelength of (visible) light is between 400-700nm, so optically (if you could get a magnifier that big I'm not sure) the smallest object you could see would be around 400nm long. I think..
So, given atoms are typically 0.1 nm or so and a water molecule is something like 0.29 nm (according to some random website) we're talking about something that's already pretty huge in particle physics terms! have a quick nosey at this, pretty interesting. Not sure how factually correct it all is. But a nice/daunting perspective to see.
http://www.newgrounds.com/portal/view/525347
http://www.newgrounds.com/portal/view/525347
itsnotarace said:
garyhun said:
I'm wanting to be here when we can see down to planck length to see if string theory is correct.
I doubt that would ever be possible, they will find other indirect ways to prove string theory is correct imhoOP said:
What's the smallest thing that can be seen?
Your cock! ho ho ho!Sorry, someone had to say it. This is the Lounge after all. The real answer has been covered above - the smallest thing we can measure is determined by the wavelength of whatever electromagnetic source you're shining at it.
Atomic Gibbon said:
OP said:
What's the smallest thing that can be seen?
Your cock! ho ho ho!Sorry, someone had to say it. This is the Lounge after all. The real answer has been covered above - the smallest thing we can measure is determined by the wavelength of whatever electromagnetic source you're shining at it.
Warning, serious answer...
The smallest thing we can see with our eye is around ten micrometers (ten millionths of a metre) across.
The smallest thing we can see with an optical microscope is around 200nm (200 billionths of a metre) across.
The smallest features we can see with a "normal" electron microscope is about 5nm across, if we're lucky. There are constraints on what we can look at - it has to conduct electricity (but we can get round this by gold-plating insulating objects), and the sample needs to be in a vacuum.
The smallest things we can see with a so-called transmission electron microscope are atoms. Here are the rows of atoms in a gold crystal. There are some constraints on what we can look at - the sample must be very thin. Often a section is taken from a larger structure.
We can image atoms more clearly with an Atomic Force Microscope. In this technique, an atomically sharp tip is moved over a sample and "feels" the location of the atoms on the surface. Here is a scanning electron micrograph (see above) of an AFM in action. Here is one result of such an experiment.
Back to willy jokes... :-)
The smallest thing we can see with our eye is around ten micrometers (ten millionths of a metre) across.
The smallest thing we can see with an optical microscope is around 200nm (200 billionths of a metre) across.
The smallest features we can see with a "normal" electron microscope is about 5nm across, if we're lucky. There are constraints on what we can look at - it has to conduct electricity (but we can get round this by gold-plating insulating objects), and the sample needs to be in a vacuum.
The smallest things we can see with a so-called transmission electron microscope are atoms. Here are the rows of atoms in a gold crystal. There are some constraints on what we can look at - the sample must be very thin. Often a section is taken from a larger structure.
We can image atoms more clearly with an Atomic Force Microscope. In this technique, an atomically sharp tip is moved over a sample and "feels" the location of the atoms on the surface. Here is a scanning electron micrograph (see above) of an AFM in action. Here is one result of such an experiment.
Back to willy jokes... :-)
A single ion (i.e. a single charged atom) can be observed directly through a normal optical microscope by confining it in a penning trap and making it fluoresce with a laser. There's a picture in Dehmelts (the chap who first built a proper Penning trap) nobel prize lecture or in his original paper http://nobelprize.org/nobel_prizes/physics/laureat...
Edited by hairykrishna on Wednesday 2nd June 22:34
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