Metal
Metals are very hard objects such as gold, silver, copper or iron.
Copper: copper is a reddish-yellow metal. These rocks are called copper ores. How is copper used? Copper coins were always less valuable than silver or gold coins, because silver and gold coins are rare metals.
Gold: gold was discovered in California in 1848. Gold is a metallic element with the number 79 and the symbol AU. The name gold comes from an old English word meaning yellow; the symbol comes from the Latin aurum, which means shinning dawn.
Iron: our planet contains a huge amount of iron. Scientist believes that the earth’s core is about nine-tenths iron. This giant ball of iron generates earth’s magnetic field and makes compasses work. What is iron used for? It is used to make automobiles and ships. It is also used for tall buildings, bridges, and making many kinds of tools.
Silver: what is silver? With the expectations of gold, silver is the most malleable and ductile of all metals. The atomic weight of silver is 107.868. What is silver? Almost everybody realizes that silver is a precious metal that is used in jewellery. Silver jewellery is usually less expensive than gold jewellery.
Different materials melt at different temperatures. Steel melts at 2500° Fahrenheit (1370° Celsius). In liquid form, steel can be poured into molds to make car frames and other products.
