This card is invisible for bear eye
By Agency - Scientists have produced what they believe is the world's smallest Christmas card. The nantotechnologists at Scotland's University of Glasgow produced the card, which features a Christmas tree etched on a tiny piece of glass. Invisible to the naked eye, the card is so small that 8,276 of them could fit on an area the size of a postage stamp.
"The card is 200 micro-metres wide by 290 micro-metres tall," Professor David Cumming, who made the card, said in a statement on the university's website. "To put that into some sort of perspective, a micro-metre is a millionth of a metre; the width of a human hair is about 100 micro-metres. "You could fit over half a million of them onto a standard A5 Christmas card - but signing them would prove to be a bit of a challenge."
The scientists say they produced it to highlight their world-leading nanotechnology expertise.