1. The Braggs and X ray Crystallography By sending radiation through crystal structures you should be able to produce diffraction around the atoms.

2. To find the structure of materials they wanted to use very small wavelengths of radiation. Why are electrons go for studying matter? Why are electrons not ideal? What could be used instead? Xrays made by slamming electrons into metals.

3. Making X rays X rays discovered in 1895by Rontgen

4. A simple explanation of what the Braggs realised.

5. path difference=nλ give constructive interference. Path difference depends on distance between lattice planes d d

6. path difference=nλ give constructive interference. let’s look at different angle rays.

7. path difference=nλ give constructive interference. for different angles path difference varies. Some angles give constructive some destructive. Braggs Law Path difference =2dsinθ=n λ

8. The Braggs realised that by sending the X rays in at different angles they should get periods of constructive and destructive interference. X ray tube target Turntable Collimating Slits The Bragg Spectrometer This would help them determine the lattice structure including d.

9. In two dimensions this type of pattern is produced. typical lattice diffraction pattern for iron

10. Realised the angle would give different patterns Used this idea to invent Braggs Law Invented the X ray Spectrometer and were able to establish the layout and spacing of atoms in a crystal. Impossible to overstate importance of this technique. X ray spectroscopy helped discover the structure of DNA Assess the impact of the work of William and Lawrence Bragg to the understanding of crystal structure.