Magnetic Force Experiment Simulation
This simulation recreates a current-carrying wire in a magnetic field using a 3D lab simulation. You can vary current, reverse polarity, and observe the force response through instrument readings.
Open the simulation here.
Core Physics Model
The simulation is based on magnetic force behaviour: $F = BIL\sin(\theta)$. In this setup, current and magnetic field are arranged perpendicularly, so the direction of force is perpendicular to both.
Force direction follows vector rules from $F = I(L \times B)$ or Fleming's left-hand rule, and reversing either current direction or magnetic field direction reverses the force direction. Simulating this experiment also teases out a common misconception by students. They would assume, by using Fleming's left-hand rule that if the magnetic force acting on the wire acts downwards, the reading on the weighing scale rises. In fact, the reading will fall. Because the force acting on the magnet is actually upward.
Switch Lever
The switch starts and stops current in the circuit. Open switch means no current and no magnetic-force effect. Closed switch enables current and force response.
Rheostat Slider
The rheostat adjusts current magnitude. Increasing current increases force magnitude, making proportional behaviour easier to observe directly.
Battery Polarity Flip
Clicking the battery reverses current direction through the wire. The force direction flips, matching Fleming's left-hand rule predictions.
Magnet Polarity Flip
Clicking the magnet reverses magnetic field direction. With current held fixed, force direction flips again.
Ammeter and Scale
The ammeter gives current in amperes, while the scale displays the force effect as a weight change indicated by a mass reading change. This links electrical input to measurable mechanical response.
Current Arrow and 3D View
The current arrow shows direction when the circuit is active, and scene rotation helps visualize the 3D relationship between current, magnetic field, and force vectors.