Rutherford's Gold Foil Experiment

While reading The Making of the Atomic Bomb by Richard Rhodes, I came across the gold foil experiment done by Rutherford in the early 1900’s that is currently used to explain the current model of the atom. Having run across this experiment multiple times in my study and readings I feel it is time to address this concept.

Rutherford and his assistants noticed that when alpha particles are fired at a piece of gold foil the will be deflected by two degrees on photographic paper. They also noticed that some of the alpha particles were shot directly back at the alpha emitter. With this evidence, Rutherford spent a year thinking about the results and experimented with electromagnets suspended so as to make a pendulum to come up with the theory that an atom contains a nucleus of charged particles that repel (like magnets) the alpha particles (which were somehow found to be positive).

Seeing as how the alpha emitter is stationary, it would seem logical that the particles emitted from it would travel in a straight line. Assuming minimal motion from the atoms within the gold foil (it is postulated that solids are still moving but the atoms stay in a relatively fixed position), the alpha particles would be deflected directly back due to the particles having the same electrical charge. We can envision this as a stationary gun shooting at a vibrating target. While the gun is being shot it does not move or alter its trajectory. The vibrating target will deflect the bullets from the gun. These deflected bullets will be shot back towards the gun with very few passing the target to the background medium.

The random few deflections that occurred in Rutherford’s experiment does show that there is a lot of space that allows particles to pass through. What it does not show is that there is a positive centre that deflects these alpha particles back towards the emitter. If we assume that physics for everything in the natural world occurs the same, the gun and target analogy would prove Rutherford’s experiment to be invalid. Even with electromagnetic pendulums being release from the exact same point with exact same trajectory, as Rutherford tried, the deflections would not occur two degrees behind the target but would be deflected back towards the emitter. Without performing this experiment myself, I cannot say whether or not the deflect particles returned in random patterns or if they struck the same point each time.

An experiment could possibly be devised where a recording medium is placed enough of a distance that the emitted particles would be deflected as Rutherford proposed- two degrees to either side of the atom- such that these deflections produce an enlarged image (enough so it can be seen through a microscope, at the very least). If the nucleus is positive and deflects two degrees on either side of the nucleus than this should produce a blank spot on the recording medium, thereby confirming Rutherford’s theory.

An argument that some have proposed is that quantum physics is different than classical physics. This surprises me since many physicists strive to find the “Theory of Everything”. If the macro world works differently than the atomic world, then they will never achieve this “Theory of Everything”. Some may agree with me and many may not, but I feel that this difference in physics indicates that there is a mistake somewhere along the line. Maybe an experiment has been interpretted incorrectly or something was missed. Maybe there was an experimental error that was not taken into consideration.

We must not take for granted that everything done in the past is absolutely correct. We must be willing to revise and revisit these concepts and see if they hold up with current technology and thinking. We must perform these experiments with an open mind, neither trying to prove or disprove lest we skew our results.