8Department for Education and Employment . 2007 science education programme of study, Jointly [DB/ OL]. http://curriculum, qcda. gov. uk.
9Zhang J.The nature of external representation in problem solving[J].Cognitive Sciense, 1997,21(2).
10McDermo,t J,Larkin J problems. In: Proceedings the Canadian Society for [M].Toronto : University of H.Re-representing textbook physics of the 2nd National Conference of Computational Studies of Inteligence. Toronto Press, 1978 : 156-164.