Rutherford Scattering is provided by PhET Interactive Simulations, University of Colorado Boulder, and is used under the CC BY-NC 4.0 licence.
1. Start with the Rutherford atom
Turn on the alpha-particle source and observe a large number of particles. What happens to most of the alpha particles?
2. Look for the unusual events
Watch for alpha particles that are deflected through large angles. How frequently does this happen compared with particles passing almost straight through?
3. Explain the straight-through particles
Rutherford found that most alpha particles passed through the foil with little or no deflection. What does this suggest about how much of an atom is empty space?
4. Investigate close approaches
Watch what happens when a positively charged alpha particle passes close to the positively charged nucleus. Use electrostatic repulsion to explain its path.
5. Change the nuclear charge
The simulation allows you to alter the number of protons in the nucleus. Predict how increasing the nuclear charge will affect the deflection of an alpha particle passing nearby, then test your prediction.
6. Compare with the plum pudding model
Switch to the Plum Pudding Atom. Observe the alpha particles again. Does this model produce the large-angle deflections seen with the Rutherford model?
7. Reach Rutherford’s conclusion
Imagine you did not know that atoms contained nuclei. From the scattering evidence alone, what could you conclude about the size, charge and concentration of mass within the atom?
Keep asking:
What must the structure of the atom be like to explain both the enormous number of alpha particles that pass straight through and the very small number that undergo very large deflections?