What is the smallest object an electron microscope can observe?

What is the range of an electron microscope? Is it enough to view cell membranes or even the double helix?


How about single atoms? And why is there a limit to its capability?What is the smallest object an electron microscope can observe?
Even atoms have been directly observed using the electron microscope. You can google for some pictures. There is a minimum size-limit though. The minimum size of the 'object' that can be observed is the De Broglie -wavelength of the electron.





Remember that particles are also waves. Now since the particle is a wave, it has a wavelength relative to its mass and velocity. A wave can never hit an object that is smaller than its wavelength. That's why. You can always increase the speed of the electrons to view smaller and smaller 'objects', but the electron-microscope requires the electrons to reflect back from the atoms, and as such increasing speed will likely destabilize the picture. Also, observing the particle (hitting it with an electron) will definitely cause the observed particle to move. So the picture gained is never the current situation, but the situation before the collision. Any observation of a particle alters its place and speed.





More about particle-waves here:


http://en.wikipedia.org/wiki/De_broglie_鈥?/a>What is the smallest object an electron microscope can observe?
Transmission Electron Microscopes have produced images with sufficient resolution to show carbon atoms in diamond and atoms in silicon, at magnifications of 50 million times.





The limit to the capability of electron microscopes is the wavelength of electrons.
I believe with electron microscopes, we can view arrays of atoms, but in black and white.





As to the limit question, when we're talking about things as small as subatomic particles, attempting to observe these particles would disrupt their natural behaviour.