technological materials, toools and wood

technological materials, toools and wood

1. raw materials

   • are products extracted diretly of nature. they maybe of plants, animal or mineral origin
   • examples: honey, wood ,gravel etc

2. natural and processed materiald

   • are applied to raw materials, also known as natural resources, to turn then into processed materials.
   • this processed materials are used to make other moro complex objects

3. the propierties of materials

   • mechanical properties
     • hardness: the resistence of a body to being hed pierced of scratcby another body
     • mechanical resistence : The ability of a body to resist the forces applied to it without breaking or changing in shape
     • toughness : A body"s resistence to being changed, deformed or broken
     • Brittleness: The ability of object to break easily, whitout being deformed hardly at all
     • Elasticity: The ability of a material to retun to its original shape after being deformed under external forces after they stop
     • Plasticity: The ability of a body to become permanently deformed whitout breakig, once its elastic limit has been exceeded
   • thermal properties
     • Expansion: The increase in size observed in a body when its temperature rises
     • Thermal conductivity. The ability to transmit heat
   • Envioroment properies
     • Toxicity: How strong a poison or toxin is
     • Envioroment hazard: The level of toxic effect contaminant has on an ecosystem
     • Biodegradability: A material"s ability to naturally decompose
     • Recyclability: The possibility of reusing a material for either the same purposed it was made for or a different one

4. Tools

   • For many centuries, humans used their hands as tool. The most primitive tools did not have handles. They were held directly in the hand and were chosen for their shape and size. The first tools had simple carved edges
   • What is a tool? : Tools may be defined as objects desing to carry out mechanical work and task

5. Wood and tpes of wood

   • Wood is the fibrous material that trees are made of. It is made up of two main substances : cellouse ( a natural fibre that forms the walls of placent cells) and lignin( which holds the cellulose together, making the tree hard and rigid)
   • Non resinous. This is a kind of wood mainly comes from trees that have little resin and fibrous texture
   • Resinus: This kind of wood usually comes from evergreen trees, which produce resin, have white or lihg colours

6. The propierties of wood

   • Hardness
   • Flexibility
   • Density
   • Thermal and electrical insulation
   • Splitability
   • Toughess
   • Hygroscopicity
   • Sound conductivity

7. Forms of wood

   • Strips
   • Moulding or profiles
   • Boards and planks
   • Beams
   • Panels
   • Sheets or Veneers