Bragg law, in physics, the relation between the spacing of atomic planes in crystals and the angles of incidence at which these planes produce the most intense reflections of electromagnetic radiations, such as X-rays and gamma rays, and particle waves, such as those associated with electrons and neutrons. For maximum intensity of reflected wave trains, they must stay in phase to produce constructive interference, in which corresponding points of a wave (e.g., its crests or troughs) arrive at a point simultaneously. The Bragg law was first formulated by Lawrence Bragg, an English physicist. The diagram shows waves 1 and 2,
It's been 70 years since the groundbreaking discovery of the DNA molecule's double helix - one of the most significant scientific breakthroughs of the 20th century and the collaborative efforts of three pioneering scientists
Letters and scientific articles by James Watson and Francis Crick tell the history of the double helix scientific breakthrough that defined the 20th century, and credit the contributions of Rosalind Franklin and Maurice Wilkins
The DNA structure breakthrough at Cambridge has led to world-changing advances in many fields, not least in biological research. But the discovery was only possible because of the work of a host of talented scientists.
The Institute of Physics is the professional body and learned society for physics, and the leading body for practising physicists, in the UK and Ireland.