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...carbon based materials used for fuel and in devices such as gas masks. However, she is better known for performing much of the pioneering X-ray crystallography that helped determine the structure of DNA. An X-ray photograph of DNA is shown in Figure 1b, and Figure 1d shows a model of its structure. In 1962 the determination of the structure of DNA using X-ray diffraction...

...carbon, each atom is covalently bonded to four other carbon atoms, arranged at the corners of a tetrahedron (Figure 16a). The resulting structure, which has a repeating cubic shape, is illustrated in Figure 16b. The structure contains much more unoccupied space than close-packed metal structures. Figure 16 The diamond structure: (a) the tetrahedral arrangement of covalent...

...carbon nanotubes to complex protein-based molecular motors. Activity 2 (example) Which is the larger distance in each of the following pairs? a.2000 mm or 1.8 m b.1 mm or 1 km Answer a.2000 mm is 2.000 m, which is larger than 1.8 m b.1 mm is 1/1000 m whereas 1 km is 1000 m, so the kilometre is larger. Activity 3 (self-assessment) a.Which is the larger distance in each of...

...footprints from prehistoric human civilisations have been found preserved in either sand or volcanic ash. From these tracks it is possible to measure the foot length and the length of the stride. These measurements can be used to estimate both the height of the person who made the footprint and also whether the person was walking or running by using the following three...