Learning Objectives - To understand the basic molecule make-up of the three main material groups - To understand a range of different physical and mechanism properties Which is stronger? Mild Steel Oak

Learning Objectives - To understand the basic molecule make-up of the three main material groups - To understand a range of different physical and mechanism properties Metals -Made up of a crystal structure -Metals have good compression and tension because of strong metallic bond -The metallic bonds have free electrons which make metals good conductors Polymers -Made up of long-chain molecules -Contain hydrogen, carbon and oxygen atoms -Also include chlorine and fluorine -Thermoplastics are held together with electrostatic bonds -These bonds weaken when heated allow the plastic to be remoulded -Thermo-setting plastics are held together with covalent bonds which are rigid cross-links -This makes them difficult to reform

Learning Objectives - To understand the basic molecule make-up of the three main material groups - To understand a range of different physical and mechanism properties Wood -Made up of organic structures -The fibrous structure is made up of resin and planet cells -This results in a strong structure along the grain -Woods are better under compression than tension -They are the same structure of both hardwood and softwood -The grains are however smaller in hardwood make it a stronger structure

Learning Objectives - To understand the basic molecule make-up of the three main material groups - To understand a range of different physical and mechanism properties Physical properties – What do the following mean? -Fusibility -Density -Electrical conductivity -Electrical insulators -Semi-conductors -Thermo properties -Optical properties -Magnetism

Learning Objectives - To understand the basic molecule make-up of the three main material groups - To understand a range of different physical and mechanism properties Mechanical properties – What do the following mean? -Plasticity -Malleability -Ductility -Elasticity -Toughness -Hardness -Durability -Stability -Strength -Tensile -Compressive -Bending -Shear -Torsional