Today’s physics news: Invisible QR codes and exam watchdog refuses to revise GCSE results

Physics news for Wednesday 12 September 2012.

Invisible QR codes could secure banknotes

Researchers in South Dakota have worked out how to create QR codes that are invisible to the naked eye. These could then be used to authenticate objects such as banknotes. The new QR codes are made from nanoparticles of blue and green fluorescent ink which are invisible to the naked eye but reveal themselves under near-infrared laser light. A smartphone can then snap a picture as normal to scan the code. The QR codes have been presented in IOP Publishing’s journal Nanotechnology.

New Scientist  

Exam watchdog refuses to revise GCSE results

England’s exams regulator yesterday refused to order new grades to be issued to candidates who sat GCSE English this summer, saying the results were fair. Head teachers’ leader demanded that exam boards be ordered to look again at the grades awarded particularly to thousands of candidates predicted C grades but who were awarded Ds. Russell Hobby and Brian Lightman, leaders of the two head teachers’ unions, told the Commons Education Committee, that teenagers were treated unfairly in GCSE English because the proportion of candidates given a C grade or higher dropped 1.5 percentage points.

The Times (Subscriber only)