Fire alpha particles at a thin gold foil. Compare two models of the atom and count how the particles move.
| Model | Straight through | Small bend | Big bend | Bounced back | Total |
|---|---|---|---|---|---|
| Plum pudding | |||||
| Nuclear atom |
Counts are random, so they change each run. Look for the pattern. Fire 100 particles at each model for your worksheet. Bounce-backs are rare. If you see none, fire 100 more.
Rutherford saw most particles go straight through and a few bounce back. Which model can make that happen?
Real foil: about 1 in 8,000 alpha particles bounced almost straight back (Geiger and Marsden, 1909). This simulation uses Illustrative data.