Rutherford's Gold Foil Experiment

The Experiment

Rutherford's team fired positively charged alpha ($\alpha$) particles at thin gold foil. They expected only minor deflections based on the "plum pudding" model. Instead, they observed that a few particles were deflected at massive angles, some even bouncing straight back. This shocking result meant the atom's positive charge must be concentrated in a tiny, dense core: the nucleus.

What to look for

• Adjust Alpha Particle Energy: higher energy particles are harder to deflect.
• Adjust Nucleus Strength: a stronger nucleus causes greater deflections (only in Nuclear Model).