How does one detect an atom?
Asked by
rebbel (
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)
September 26th, 2011
With last week’s news about the speedy neutrinos from CERN, a question that I have had for ages came back to mind again:
How does one detect an atom?
Obviously there was a first time that someone went home after work and told his/her spouse “Dear, I found an atom today!”
But how?
A microscope?
Did he/she had to cut the material with a knife in very small parts first?
To someone who knows, explain it to me in simple words imagine I am your old aunt, please.
If there is some time left: same question for the neutrino, the (almost) undetectable part?
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11 Answers
Thank you very much, @silverangel !
I am sure it will, but what I am looking for is a very simple explanation.
For me, with English as a second language and (close to) no knowledge of physics lingo, even a Wikipedia page on the subject is too much to grasp.
With a really, really special microscope…
Picture boiling water with tiny little seed pearls in it. When the bubbles capture the seed pearls they get trapped inside and the microscope can’t see them yet. The event of the [heat] in this case, but a curved electron field in the case of the real microscope, which causes the water to rise toward the microscope.
As it sits on the surface, the microscope captures the seed pearls as the bubbles that encapsulate them burst and release them at the top of the vessel. Then we can “see” them *meaning capture them with the microscope.
I hope that makes sence? Please feel free to correct… I thought about this and couldn’t come up with a better analogy that was simple. Sorry, I tried
Please don’t apologize, @GabrielsLamb, you did a fine attempt!
Not sure if I got it completely, but I will sleep on it and reread it in the morning.
Thank you!
It depends on whether you mean imaging an atom or just detecting it. Atoms were first detected in 1909 with the Geiger-Marsden experiment. But they weren’t imaged until 1981 with the scanning tunneling microscope
And just to summarize the Geiger-Marsden experiment, they shot alpha particles (helium nuclei) at a gold foil. Most of them passed through like there was nothing there, but a few bounced at crazy angles when they banged off an atom.
First of all, neutrinos are not atoms.
Particles can be detected by observing their effects on other particles. When a particle slams into a substance which we are observing, we can see what changes were made to it, and thus infer properties about the incident particle.
@Ivan and @others: Thank you!
@Ivan By the way, I didn’t say that they are the same, neutrinos and atoms, I believe.
@rebbel Okay, sorry, I must have misinterpreted.
@rebbel I think I got stuck on the “Old aunt” part… I can easily explaint it in complex terms if you like… Seems making things simple as possible is the difficult part.
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