METALS
CHEMICAL ELEMENTS can be divided into several groups.The largest group, which forms about three-quarters of all elements, is metals.Metals have many features that other elements do not possess.They carry heat and electricity well compared to non-metals.They are solid at normal temperature. They are hard and strong and they can be polished to give a smooth,shiny surface.Metals have high melting and boiling points.The metal mercury is silvery liquid at room temperature.
The Statue of liberty in New York
is made of a shell of copper held up
by a frame inside.
Copper is brown when clean.
After a time exposed to air it develops
a green covering of copper oxide.
Metals are very important in the modern world. Due to their strength and hardness they are used to make all kinds of machines and structures.The most widely used metal in industry is iron but not usually in its pure form.Iron is mixed with other substances,to form steel.A metal mixed with other substances is known as an alloy.
There are hundreds of different kinds of alloy steels, each each with slightly different amounts of carbon and other elements,and each can do a different task. Stainless steel is used for sinks an cutlery. Titanium and vanadium steels resist very high temperatures without melting.
In a suspension bridge ,the road or railway is hung from massively thick cables made from steel which is highly tensile(resists stretching)
More about metals
More about metals