- Created by: charlie_riley
- Created on: 19-01-18 11:53
density and changes of state
density tells us how much mass there is in a certain volume it is a property of a material
the relationship between density, volume and mass can be summed up in the following equation: density = mass divide volume
density, p, is mesaured in kilograms per metre cubed (kg/g)
mass, m, is mesaured in kilograms (kg)
volume, v, is mesaured on metres (m)
density is the mass per unit volume of a material, or the mumber of kilograms (Kg) contained in 1m of the material.
DENSITY AS A PROPERTY OF A MATERIAL
the density of a marterial does not change when we change the volume of an object
for example we could take a 1m block of material that weights 1000kg. its density is: 1000 didivde 1 = 1000(kg/m)
if we stick another identical block onto this, the volume is now doubled to 2m but so the mass. the density can be caluclated again: 2000 didvide 2 = 1000kg/m. its stays the SAME.
COMPARING DENSITIESB OF MATERIALS
we can easily compare the density of diffrent materials using a balance
we can see that the density of the red object is 10 times that of the green
they have the same mass but it is contained in a much smaller volume for the red object.
in order to calculate the density of an object, the volume and mass of the object must first be measured
measuring mass is easy. we can use an electronic BALANCE
measuring the volume of regular shapes can be done using mathematical formulae
for example, for a cube w ecan simply mulitply the lengths of the sides, for a sphere we can use a mathematical formula the dimensions of an object can be mesaured using a ruler a vernier callier or a micromenter, depending on the size.
we can then divide the mass by the volume to find the density.
MEASURING IRREGULAR VOLUMES
there is no mathematical formula to find the volume of irregular shapes. instead a simple experiment…