KS 4-5
A wonderful animation to explain how metal detectors work is at http:micro.magnet.fsu.eduelectromagjavadetectorindex.html
We may not know what cables and pipes are underground but what sensors can be put underground to detect what’s going on above? A good overview is at www.epa.govwatersecurityguideexteriorburiedintrusionsensors.html. Ideas on sensor building can be found at http:advancingphysics.iop.orgresourcesOCRCswkGuide.pdf There are lovely activities on what’s underground in Salters Horners Advanced Physics AS.