physical properties of matter
def: qualities that can be detected using our five senses / a measuring device.
- flexibilit ability to bend w/o breaking
- hardness ability to withstand scratches (if an x is scratched by y, then y is harder than x)
- melting point temp @ which smth changes state fr solid to liq
- boiling point temp @ which smth changes state fr liq to gas
- thermal conductivity measure of how quickly heat passes through smth
- electrical conductivity measure of how readily electricity passes through smth
- density quan. of matter packed into a unit vol of the mtrl (if an obj is put in a liq and it sinks, its density is > the density of the liq)
things to consider when choosing a mtrl to make smth:
- what purpose does the obj serve?
- what physical properties does the obj need to have?
- does the mtrl cost too much?
units of measurement**
- length m
- mass kg
- temp K (Kelvin)
- time s
- volume m3 [cm3, l, ml]
- density g/cm3 or kg/m3
- pressure Pa (Pascal) or N/m2 or N/cm2 (depending on the qn)
- force N
- area m2 or cm2
- energy/work J
def.: the quantity of matter in a material packed into a unit volume of the material
formula: density = mass / volume
- amt of matter in an obj
- does not change no matter where you go
- measured in g or kg
- amt of space an obj occupies
- for the same amt of space a gas occupies, the vol may be diff bec gases are compressible
- measured in l, ml, cm3 or m3
density question - z grams of x is mixed with w grams of y to obtain a mixture. the volume of this mixture is z cm3. find the density of the mixture.
ans: total mass / total volume = density of the mixture