Chapter 2, Problem 8E

Predict and test the behavior of a particles fired at a “plum pudding” model atom.

1. Predict the paths taken by a particles that are fired at atoms with a Thomson’s plum pudding model structure. Explain why you expect the $\alpha$ particles to take these paths.
2. If a particles of higher energy than those in (a) are fired at plum pudding atoms, predict how their paths will differ from the lower-energy a particle paths. Explain your reasoning.
3. Now test your predictions from (a) and (b). Open the Rutherford Scattering simulation
(http://openstaxcollege.org/I/16PhetScatter) and select the “Plum Pudding Atom” tab. Set “Alpha Particles Energy” to “mm,” and select “show traces.” Click on the gun to start firing a particles. Does this match your prediction from (a)? If not, explain why the actual path would be that shown in the simulation. Hit the pause button, or “Reset All.” Set “Alpha Particles Energy” to “max,” and start firing a particles. Does this match your prediction from (b)? If not, explain the effect of increased energy on the actual paths as shown in the simulation.