atom

smallest part of an element that can exist chemically

atoms

smallest part

molecule

two or more atoms bonded together

bond

force of attraction between two atoms

strength of primary bonds

ionic>covalent>metallic

timber

natural wood or man-made

metals

ferrous (iron) or nonferrous (no iron)

plastics

thermoplastics and thermosets

ceramics

glass

textile fibers

natural or synthetic

composites

always changing, many here (ex: kevlar, carbon fiber…)

physical properties

measurable properties which describe a physical state

density

physical - mass/unit volume

electrical resistivity

physical - materials ability to conduct electricity

thermal conductivity

physical - measure of how fast heat is conducted through a slab of material

thermal expansion

expansivity

physical - change in size due to temperature

hardness

physical - resistance to penetration or scratching

tensile strength

mechanical - strength against pulling forces

mechanical property

behavior of the material when its linked to the application of force

compression strength

mechanical - strength against pushing forces

stiffness

mechanical - resistance of an elastic body to an applied force

toughness

mechanical - combination of strength and ductility

mechanical - withstand sudden shocks or blows without fracturing

mechanical - withstand cracking when subjected to bending/shear forces

ductility

mechanical - bendability or crushability and stretch (opposite of brittleness)

malleability

mechanical - deform in all directions by hammering and pressing without it cracking or splitting cannot stretch

elasticity

mechanical - ability for an object or material to resume its normal shape after being stretched or compressed; stretchiness

plasticity

mechanical - quality of being easily shaped or molded ( does not return to its original form/state

aesthetic properties

activate people’s senses; taste, smell, hearing(sound), sight(appearance), touch(texture)

natural timber

composite material comprised of cellulose fibers and lignin matric (glue)

conifer trees

softwoods

grow in temperate regions

30 years to mature

less dense, fast growth

needle and cone seeds

tracheids for fluid transport

deciduous trees

hardwoods

temperate AND tropical regions

100 years to mature

slow growth, more dense

flat leaves

long continuous ducts for water transport

seasoning

drying

planing

to smooth the wood

composite timbers

particle board

plywood

OSB

MDF