Britain's annual Festival of Science opened yesterday in Cardiff, the 167th festival to be organised by the British Association for the Advancement of Science. The event brings together hundreds of researchers ranging across all scientific disciplines who present their work in sessions open to the public. The object is to bring the latest developments in the sciences to the widest possible audience without jargon and using ordinary non-technical language. Those in attendance are also encouraged to put questions to the presenters. The theme chosen for this festival is The Challenge for Science, meant to reflect the two sides of scientific endeavour, the intellectual pursuit and the often striking moral challenges thrown up by the pace of discovery. The Festival continues until Friday evening.