Luckily for us, metals are abundant: together they form a quarter of the earth's crust (oxygen makes up half, and silicon a quarter). Unfortunately, most metals (with the exception of gold and silver) don't occur in a form ready for us to use, instead we have to extract them from minerals that contain chemical compounds of metals. Digging these minerals (called ores) out of the ground, and treating them chemically to extract pure metals is not easy, but the results are clearly worth the trouble.

Most metals share some common features. Most (excluding mercury) are hard solids with high melting points. They are malleable, meaning they can be pressed or bent into many shapes without breaking. They are also ductile, meaning they can be pulled or drawn into long and thin wires, again without breaking. Most have a "metallic" shine or luster. The shiniest - gold, platinum and silver - are used to make jewelry. Metals are good conductors of heat and electricity. Finally, metals react easily with their environment (air, water, ...) - this is why we cannot find most metals in their pure state but must extract them from minerals (remember?).

However, all metals are NOT alike. The graph above shows the density of twenty common metals. The heaviest, platinum, is over twelve times heavier than the lightest, magnesium. Gold, tungsten, and uranium are dense; aluminum and titanium are light metals.

Some metals are very hard, others less so. Harder metals can scratch softer ones. Lead and tin are the softest metals. Chromium is the hardest, followed by tungsten. The graph on the right shows the hardness of the twenty common metals on the Mohs scale of hardness. This scale goes from 1 to 10 (1 is as soft as talcum powder and 10 as hard as diamond).

Mercury is the only metal that is liquid at room temperature (it freezes at -39C). All others melt at relatively high temperatures. Molten metals boil at even higher temperatures. The graph below shows the melting and boiling points of the twenty common metals. Among metals, tungsten, and molybdenum have the highest melting points.

This website holds a ton of information about metals. We describe how metals made human civilization possible through the ages, and all the common metals you are likely to come across - where they are found and what they are good for. You will see that metals have a dark side as well. Many are used in wars that claim many lives, and quite a few are toxic to our health if not disposed properly.