Why can iron filings be used to study the magnetic field?

In a magnetic field, iron filings are magnetized and turn into magnetic mini-spheres, each axis in a magnetic field is set along the direction of action of the magnetic field forces.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.