IB Rutherford PHET Lab

Click Here to run the PhET

Wait for the PHET to load. Click "Rutherford atom"

Click the blue button on the left to start the alpha particles going

Click the "Traces" box in the "Alpha Particle" menu

The yellow dots are the nuclei. The purple space invaders flying from bottom to top of the screen are the alpha particles. Both of these are positively charged, so they repel each other. Watch them for awhile before proceeding.

Why are some alpha particles largely undeflected, and some of them are strongly deflected? What makes the difference?

On the top left side click the lower image of the nucleus. Observe the alpha particles and change the energy of the alpha particles from low to high

How does the energy affect the distance of closest approach? How does it affect the amount of deflection?

On the very bottom menu, click the "Plum Pudding atom" and turn the alpha particles back on. (And turn on the "Traces")

How much deflection of alpha particles does the plum pudding model predict?

What two problems of the Rutherford atom did Bohr's Model seek to fix?

1. (The first was that the Rutherford atom did not explain something rather striking about the light atoms emitted - what was that thing, and how did the Bohr atom explain it)

2. (The second issue was that the Rutherford atom was energetically impossible. Why was it impossible, and how did Bohr's atom get around that)