METALS

METALS

1. What are metals?

   • chemical elements are organised in the periodic table

2. types

   • -solid -liquid -alloys -four

3. properties

   • -are very dense -good heat electric conductor - reflect the light -are solid at room temperature -they ca be mixed with other metals

4. obtaining metals

   • mining and metallurgy ,open-pit mines,uderground mines,the enviromental impact of extracting metals

5. envirometal problems

   • mining spoils the landscape:forests have to be felled,especially for open-pit mining
   • it alters the soil structure as a result of building both tunnels and benches.When a mining operation comes to an end ,the solid must be replaced in order to prevent landslides.
   • blasting(small explosions to remove rock)produceds and smoke pollution.
   • some metals and refining processes are toxic
   • explosions and moving heavy machinery produce sound pollution.

6. metalworking tools

   • drilling tools
     • punches:is a cylindrical piece of metal with a pointed end.
     • drill bits:parts that are coupled to the drill and which are responsible for making holes
     • drills:2 types:hand drills and drill presses
   • cutting tools
     • used to work with metal are similar to those used to cut wood.
   • filing tools
     • grinders or emery grinders:are machine tools that have an abrasive stone,known as a grindstone,coupled to them.
     • files:is a steel bar with a rough surface.
     • sandpaper:paper with small grains of silicon dioxide glued to its surface.