Teen's 'solar death ray' can melt concrete
http://www.smh.com.au/technology/sci...204-1afxk.html
"A US teenager has built his own "solar death ray" out of thousands of mirrors that is capable of melting anything from metal to concrete.
Eric Jacqmain, 19, from Indiana, demonstrated the $US90 contraption in a
YouTube clip and claims it offers the "power of 5000 suns". That claim is likely an exaggeration but the clip shows the ray can melt pretty much any object.
It is essentially a fibreglass satellite dish covered in 5800 small mirror tiles, which focus the sunlight into a spot the size of a coin when positioned correctly..."