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Science modified

  1. 1. SCIENCE <br />KS2<br />
  2. 2. materials<br />
  3. 3. Metals<br />Imagine world without METALS. There would be no cars or aeroplanes, and skyscrapers would fall down without the metal frames that support them.<br />Metals have countless uses because the poses a unique combination of qualities. They are very strong and easy to shape, so they can be used to make all kinds of objects from ships to bottle tops.<br />All metals conduct electricity. Some are ideal for wires and electrical equipment.<br />Metals also carry heat, so they make good cooking pots<br />
  4. 4. Metals <br /> continue <br />These qualities can be improved by mixing two or more metals to make alloys. Most metallic objects are made of alloys rather than pure metals.<br />There are more than 80 kinds of pure metals, though some are very rare. Aluminium and iron are the most common metals.<br />A few metals, such as gold, occur in the ground as pure metals; the rest are found as ores in rock.<br />Metal can also be obtained by recycling old cars and tins. This reduces waste and costs less than processing metal ores.<br /><br /><br />
  5. 5. Aluminium<br />The most common metal in the Earth’s crust is aluminium. The metal comes from an ore called bauxite, which contains alumina, a compound of aluminium and oxygen.<br />Aluminium is light, conducts electricity and heat, and resists corrosion. These qualities mean the metal and its alloys can be used in many things, including:<br /><ul><li>aircraft and bicycles,
  6. 6. window frames,
  7. 7. paints
  8. 8. saucepans
  9. 9. and electricity supply cables.</li></li></ul><li>Alloys<br />Most metal objects are made of steel or other alloys. This is because alloys are often stronger or easier to process than pure metals.<br />Copper and tin are weak and pliable, but when mixed together they make a strong alloy called bronze.<br /><ul><li>How is copper used in the Statue of Liberty?</li></ul><br />Brass is a tough alloy of copper and zinc that resists corrosion.<br />Alloys of aluminium are light and strong and are used to make aircraft.<br />
  10. 10. Pure metals<br />The rarity and lustre of gold and silver have been prized for centuries.<br />What is gold use for ?<br /><br />Other pure metals have special uses:<br />- electrical wires are made of copper, which conducts electricity very well<br />- mercury, a liquid metal is used in thermometers.<br />
  11. 11. metalworking<br />There are many ways of shaping metal. Casting is one method of making objects such as metal statues. Hot, molten metal is poured into a mould where it sets and hardens into the required shape.<br />Metal can also be pressed, hammered, or cut into shape.<br />Watch an animation about steel-rolling:<br /><br />