Electron Size and Energy: Exploring Rutherford's Gold Foil Experiment

  • Thread starter granpa
  • Start date
  • Tags
    Electron
In summary, Rutherford conducted an experiment where he fired high-speed alpha particles at gold foil and observed that some rebounded directly back, leading him to conclude that the gold nucleus must be very small. However, firing electrons at gold or protons does not provide an accurate measurement of the electron size due to their larger sizes. High-energy scattering experiments have been able to probe down to a radius of 10^-20 meters, which is still consistent with a point-like electron. Hans Dehmelt's experiments resulted in an even smaller upper limit for the electron radius, further supporting the theoretical model of a point-like electron.
  • #1
granpa
2,268
7
everyone knows that Rutherford fired alpha particles at high speed at gold foil and some rebounded directly back and that from this he concluded that it must be very small. what about electrons. if electrons are fired at high speed at gold foil then do some rebound directly back? how far down does this sort of experiment show the field of the electron extending to.

how much energy can electrons have and still rebound directly backwards?
 
Physics news on Phys.org
  • #2
I don't know about gold foil, but there has been at least one high-energy accelerator used for electron-proton collisions: HERA at DESY in Hamburg, Germany.
 
  • #3
It should be emphasized that Rutherford discovery is not merely about some backwards scattering. It's about the angular distribution of the scattering. In fact, most of the alphas were almost not deflected, indicating that the gold nucleus was smaller than Thomson's "plum pudding".
 
  • #4
Firing electrons at gold or at protons does not measure the electron size, because the gold and the proton are too big themselves. Electron electron scattering is consistent with scattering of point charges. The accuracy of the experiments provides a very small upper limit to the electron radius.
 
  • #5
The tightest upper bound on the electron radius that I'm aware of is [tex]r < 10^{-22}[/tex] meters, from http://www.iop.org/EJ/abstract/1402-4896/1988/T22/016/. High-energy scattering experiments can probe down to [tex]r \sim 10^{-20}[/tex] meters, if I recall correctly, at which distance the electron still "looks pointlike".
 
  • #6
Hans Dehmelt won the Nobel prize for experiments like that. His result is a smaller upper limit than e-e scatering. All measurements are consistent with a point-like electron, which is the preferred theoretical model.
 

1. What is Rutherford's Gold Foil Experiment?

Rutherford's Gold Foil Experiment was a scientific experiment conducted by Ernest Rutherford in 1911, in which he bombarded a thin sheet of gold foil with alpha particles to study the structure of the atom.

2. What did Rutherford's Gold Foil Experiment reveal about the structure of the atom?

The experiment revealed that the atom is mostly empty space, with a small, dense nucleus at the center. This contradicted the previously accepted model of the atom, known as the plum pudding model.

3. How did Rutherford's Gold Foil Experiment contribute to our understanding of electron size and energy?

By observing the deflection of alpha particles as they passed through the gold foil, Rutherford was able to determine the size of the nucleus and the amount of energy needed to penetrate it. This provided valuable insights into the size and energy of electrons within the atom.

4. What is the significance of Rutherford's Gold Foil Experiment in the field of nuclear physics?

The experiment played a crucial role in the development of modern nuclear physics, as it provided evidence for the existence of a small, dense nucleus within the atom. This paved the way for further research and discoveries in the field of nuclear energy and atomic structure.

5. How does Rutherford's Gold Foil Experiment relate to current atomic models?

While Rutherford's experiment disproved the plum pudding model and led to the development of the nuclear model of the atom, it is still relevant in modern atomic theories. For example, the concept of electron energy levels, which is a fundamental part of the modern atomic model, can be traced back to Rutherford's observations of electron deflection in the gold foil experiment.

Similar threads

Replies
3
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
1K
  • Classical Physics
Replies
23
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
2
Views
2K
  • Other Physics Topics
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
4
Views
1K
  • Other Physics Topics
Replies
2
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
4K
Back
Top