1. Manufacturing technical objects

2. Materials
To decide which materials are suitable for making technical objects (made of one or more materials) manufacturers must first determine the stress/possible deformations the objects will be exposed to.

3. A constraint describes the effect of external forces on a material
(p. 387 of your textbook)
Main types of constraints:
Compression: (squeezing/crushing)
Tension: (stretching)
Torsion: (twisting)
Deflection: (bending)
Shearing: (cutting)

4. Three types of material deformation (p.387)
Elastic: temporary change in shape
Plastic: permanent change in shape
Fracture: death of the material (breaks)

5. Properties (p )
Mechanical properties: how a material reacts when subjected to one or more constraints.
Hardness: ability to resist damage/scratches
Elasticity: ability to return to original shape
Resilience: resist shocks without breaking
Ductility: can be stretched without breaking
Malleability: can be flattened without breaking
Stiffness: ability to retain shape when subjected to various constraints

6. Other properties
Resistance to corrosion (resist effects of corrosive substances like water and salts which cause the formation of rust)
Electrical conductivity ( ability to carry an electrical current)
Thermal conductivity (ability to transmit heat)

7. Degradation and Protection (p. 389- 390)
Degradation of a material : decline of its properties due to the effects of the surrounding environment
Protection of a material : application of procedures that prevent or delay degradation

8. In class work P. 418-419 Questions 1 to 6 ***Assignment***
Using everyday household items attempt to build a support for books. See how many books your support can...support. Work in pairs but hand in individual reports. Your report should make reference to the terminology seen on material and have the standard lab report format.