To celebrate the centenary of J J Thomson’s discovery of the electron, the Institute of Physics and American Physical Society are inviting secondary school and college students to enter a poster competition. Entries should illustrate the importance of the electron in our lives. A trip to the US will be awarded to seven winners and other prizes include a computer with Internet link for the prizewinner’s school. Closing date: April 30. Details: Katie Perry, Institute of Physics, 76 Portland Place, London W1N 4AA, tel: 0171 470 4800; e-mail: katie.perry@iop.org