Sarah Cull and Isabel Urquhart show off their scientific knowledge in the national final of a physics competition held in Birmingham yesterday.

The 15-year-olds from King Edward VI High School for Girls, Birmingham, demonstrated their project using soap bubbles at the Paperclip Physics Competition held at the city's ThinkTank museum.

The duo were part of a King Edward team demonstrating the patterns of colour and light through soap.

The event, organised by the Institute of Physics, enabled students to explain some of the most complex ideas in physics using everyday objects.

Just 13 teams out of 1,500 children were picked for the final competition following a series of regional events. The winning team was from Altrincham Girls' Grammar School.

At the grand final yesterday, a team from Sydenham High School in London explained why only pond skaters and prophets can walk on water, and a team from Emmanuel College in Gateshead performed a sketch of James Bond jumping on to a moving train to demonstrate their knowledge of forces.

They staged an argument between the film director and actor about why 007 would be forced backwards if he was on top of the train.

Dr Liz Parvin, coorganiser of the competition said: "Paperclip Physics has been designed to test the students' ingenuity, understanding of a physics principle, ability to work in teams, and to communicate their understanding to non-scientists."