Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Blocking Magnetism
Name: angel
Status: student
Age: 18
Location: N/A
Country: N/A
Date: 1999 

can anything block magnitism?

Yes, you can shield against magnetic fields using any magnetic material. One of the most effective shields is a material called mu-metal. The idea is to 'trap' all the magnetic lines of force within the metal and thus preventing it from affecting other objects in the area. To be completely effective the shield should completely surround the object you are trying to protect.


Electrical conductors attenuate a magnetig field. Superconductors exclude a magnetic field entirely. That is the physical basis for "magnetic levitation": magnetic fields actually repel superconductors.

Richard Barrans Jr., Ph.D.

you cannot really block magnetism, what "comes out" of a magnet (its field lines, in our imaginary world) must go back in somewhere. BUT you can redirect them with a magnetic material like soft iron. This is commonly done. If there is some instrument or machine that is sensitive to stray magnetic fields, even that of the earth, then that device can be wrapped in soft iron (there is a thing called mu metal, just iron really). It diverts the magnetic field away from the sensitive area.


Yes. Magnetic fields behave in much the same way as electric fields at an interface between two materials, though the characteristic of the materials that is important are different. For magnetic fields, the important characteristic is the magnetic permeability, and a high- permeability material like iron or mu-metal can be used to shield against a magnetic field. A superconductor is an even better shield.


Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory