Photography has been made possible by the effect of light on metal salts. Metals are excellent conductors of both heat and electricity. Thermal conductivity is harnessed in automobile radiators and cooking utensils. Electrical conductivity provides society with the ability to transmit electricity over long distances to provide lights and power in cities remote from electrical generating stations. The circuitry in household appliances, television sets and computers relies on electrical conductivity.
Metals are hard and durable.
They are used in applications sensitive to corrosion such as chemical plants, food preparation, medical applications, plumbing and lead in storage batteries. Wear resistance is critical in bearings for all modes of transportation and in machine tools. Fatigue resistance the ability to resist breaking after repeated deformation such as bending enables the use of metals in springs, levers and gears. Temperature resistance makes metals suitable for jet engines and filaments in light-bulbs. Metals are uniformly lustrous and, except for copper and gold, are silvery or greyish.