Lecture 1

Question 1

What is a single-crystal?

Answer 1

one crystal orientation

Question 2

What is a poly-crystal?

Answer 2

crystal “grains” with different orientations

Question 3

What do we focus on with poly-crystals?

Answer 3

how internal arrangements affect properties

Question 4

What is an amorphous?

Answer 4

a solid with no crystal structure, no symmetry, no periodicity

Question 5

What do you need to understand the properties of a material?

Answer 5

how the material is arranged internally, how the atoms are arranged in the lattice, indicates most of the properties of the material

ex: arrangement of graphite and diamond

Question 6

What are some differences between diamond and graphite?

Answer 6

Diamond
1. 3D structure
2. carbons in tetrahedral
3. strong, rigid, hardest known material
4. electrical insulator
5. disperses light
6. transparent

Graphite
1. planar arangement
2. soft, lubricant
3. good heat and electrical conductor
4. absorbs light
5. grey/black

Question 7

Who was the first to relate the external shape to internal order?

Answer 7

Johannes Kepler

suggested the hexagonal shape of a snowflake (only 6 corners) because snowflakes are arranged in a hexagonal arrangement

Question 8

What did robert hooke do?

Answer 8

he suggested that the different shapes of the crystals at the microscopic level is due to the packing of spheres

observed that “packing” leads to facets that are 60 or 120 degrees (from close-packing hexagonal)

Question 9

What did Hauy show (and in what year)?

Answer 9

that the packing of the underlying blocks of influence the shape and angulgar relationship between crystal facets in 1984

Question 10

more info on this slide

Question 10

What discoveries were made in the mid 1850s

Answer 10

Crooke’s tube study of “cathode rays” or a stream of electrons

1. electrons accelerated from anode to cathode
2. they detected it from the growing tube

Question 10

What contribution did Wilhelm Conrad Rontgen have? What was his first picture of it?

Answer 10

there was a new “unknown” type of radiation, X-rays

first X-ray was a picture of his wife’s hand with her ring on

Question 10

What is the order of the waves and their wavelengths?

Answer 10

large to small
radio, micro, infared, visable, ultraviolet, x, one more

Question 11

What are X-rays?

Answer 11

electromagnetic radiation with wavelength A