Simplify the following text for a Grade 9 native English-speaking person.
Original: The magnetic field can be estimated at any point on a magnetic field line diagram ( whether on a field line or not ) using the direction and density of nearby magnetic field lines .
Simplified: Magnetic fields give power to other particles that come in contact with the magnetic field . In physics , the magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles .