Magnetic wood to make mobile phones silent

The prayers of every teacher, theatre-lover and concert-goer might soon be answered, by "magnetic wood" that stops mobile phone users in mid-sentence.

Japanese researchers say they have developed a panelling packed with magnetic particles that will block mobile phones' microwave radiation.

The research team's leader Hideo Oka, from Iwate University in Japan, told New Scientist magazine that anyone wanting to prevent people using mobiles on their premises could use the wood-based panels in their interior design.

Energy from the phone signals is absorbed by tiny particles of nickel-zinc ferrite. The size of the particles has to be roughly tailored to the frequency of the phone signals.

Researchers believe the panels could help to overcome a newly discovered problem with wireless computing networks in Japan where different networks sometimes interfere with each other.

But there is a long-term risk to people attempting to use their mobiles in such a building because the panelling would cause the phones to increase their output – potentially raising the exposure of their owners to the radiation.