Give examples of single crystals and polycrystals.

Single crystals — single crystals — have a regular geometric shape. In the form of individual single crystals, there are, for example, table salt, granulated sugar, quartz, ice. A solid, consisting of a large number of small crystals, is called polycrystalline. Usually metals consist of a huge number of small crystals grown together with each other. The properties of each crystal depend on the direction, but the crystal crystals are randomly oriented in relation to each other. As a result, in a volume that significantly exceeds the volume of individual crystals, all directions within the metals are equal and the properties of metals are the same in all directions.