Physics High: the Hall effect

Start with the commuter picture, then switch tabs to see the same thing as real physics. The sliders stay in step.

Commuters stream down a corridor while an invisible hand shoves them sideways. What happens to the crowd?

Controls

What the crowd is doing

Crowd imbalance between the two walls
0.00
Even crowd, nothing lopsided yet
The shove
Crowd pushes back
The probe meter turns the imbalance into 0 mT.

The story in three beats

The invisible hand shoves every commuter toward one wall.Physics: the magnetic force on a moving charge, F = qvB.
The crowd bunches against that wall and starts pushing back.Physics: charge builds up on one edge, creating an electric field and force F = qEH.
Shove and push-back match, so everyone walks straight again, but the lopsided crowd stays.Physics: qEH = qvB, so the Hall voltage VH = vBw stays steady.

Crowd sizes and pushes are shown in arbitrary units to keep the idea clear.