Magnetic Domains — Simulation

Drag a magnet to move it. Tap a magnet to reverse its direction.

Think about it

Drag one magnet into the iron bar. What does the meter read? Add a second one pointing the same way. What happens?
Now reverse one of them by tapping it. The reading changes by two, not one. Why?
Press Scramble. The bar is full of magnets, so why does the needle sit near the middle?
Press Line them all up. What is the largest reading you can get, and what does that tell you about a fully magnetised piece of iron?
Slide a magnet along the bar toward the meter without turning it. The reading creeps up. Now reverse that same magnet instead. Which change was bigger, and what does that tell you?
Can you make the needle swing the other way? What would that mean about the bar?