 In this video, you're going to examine the uses of metals. The periodic table of elements has 91 pure metals in it. How many can you think of? The properties of these metals are due to their atomic structure, as is their position in the periodic table of elements. This atomic structure also has a bearing on how the metals are used. Consider some of the most unreactive metals you know of. These metals may be gold or silver. Think about how these metals are used. They are valuable, perhaps more important in terms of their use, is that they are very unreactive. They do not react with air or water. A ring or jewellery is often given as a special gift. Because of its unreactive nature, the jewellery remains shiny and untarnished. Copper is also an unreactive metal. Can you think of a use for copper? Because it does not react with water, being below hydrogen in the reactivity series. Copper used to be used for the construction of water pipes. You may have copper pipes carrying water around your home. Copper is also malleable and can be bent easily without cracking, so it can be made to bend around corners. As well as its low reactivity, the ability of copper to conduct electricity is important. When considering how it's used, copper is a good conductor of electricity and is duct time. This means it can be drawn out into long wires. Perfect for carrying electricity from place to place. Aluminium is another metal that's been specifically used because of its characteristics. Aluminium will react with oxygen in the air to form a layer of aluminium oxide. This layer is relatively strong and can protect the main body of the metal. The fact that the aluminium reacts in this way means that it can be used for the bodies of trains. It does not need painting and its tarnished look is protective of the layers below. Aluminium is also used for the bodies of planes. Aluminium is less dense than many metals, making it light. It can also be made stronger, making it into an alloy. This aluminium alloy can be bent easily to form the body of the plane. Steel is another metal which has changed the face of the earth and the way humans use the materials around them. Steel is also strong, but perhaps more importantly, it is cheap to make. Iron, when combined with carbon, becomes the compound steel. Iron by itself is a weak metal, but when carbon is added to form steel, it becomes considerably stronger. Iron has been in plentiful supply and used by humans for thousands of years. Steel has been discovered by different cultures at different times in history, but particularly the replacement of iron by steel in industry and construction since the 19th century changed the face of the earth. It has allowed for the building of many large constructions, such as bridges, much stronger and able to last far longer than previous constructions. So in summary, there are a wide variety of metals which humans have exploited for their varying properties. Some metals are unreactive with water and air, making them useful for jewellery and piping. Some metals are less dense than others and therefore useful for the aerospace industry. Some metals are good conductors of electricity.