Although we cannot see magnetic field lines, we can detect them using iron filings. The tiny pieces of iron line up in a magnetic field.

Magnetic fields reveal incredible patterns that remain unseen to the naked eye. Various techniques bring these invisible forces to life, showcasing their mesmerizing effects in action. From iron ...

Scientists have captured faint magnetic signatures resulting from the tidal movement of seawater across the planet — and they ...

The iron filings in the image become induced magnets when they are near the bar magnet. They lose most or all of their magnetism when they are removed from the magnetic field.