A LEADING researcher from Exeter University will visit Okehampton College next week to describe her work in developing invisible materials. The free presentation by theoretical physicist Claire Woollacott is sponsored by the Institute of Physics and is suitable for those aged 13 upwards. The public presentation takes place in the college's Octagon Theatre at 7.30pm on Tuesday, September 16. To reserve places contact Keith Webber on [email protected]">[email protected] The presentation lasts an hour, and all are welcome.