DENSITY Q) Which weighs more:- A kilogram of feathers or a kilogram of iron? DENSITY

Density is the Mass per unit Volume What is Density? If you take the same volume of different substances, then they will weigh different amounts. Wood Water Iron 1 cm3 1 cm3 1 cm3 IRON 0.50 g 1.00 g 8.00 g Q) Which has the greatest mass and therefore the most dense? Density is the Mass per unit Volume

Density Equation: = m V m V  Mass Density = Volume Example: g or kg m V  Mass Density = Volume gcm-3 or kgm-3 cm3 or kg3 = m V Example: Q) Liquid water has a density of 1000kgm-3, while ice has density of 920kgm-3. Calculate the volume occupied by 0.25kg of each. V = m = 0.25 = 0.000250m3  1000 V = m = 0.25 = 0.000272m3  920

DENSITY OF A REGULAR SOLID Find the Mass of the solid on a balance. Measure the three lengths and calculate the Volume. (ie V = l x w x h ) Calculate the Density. m = 240 g 2.0 cm  = m = 240 =10.0 g/cm3 V 24 3.0 cm 4.0 cm

DENSITY OF AN IRREGULAR SOLID m = 360 g  = m = 360 =12.0 g/cm3 V 30 Find the Mass of the solid on a balance. Fill the Measuring Cylinder with Water to a known Volume. Add the Object. Work out the Volume of Water that is displaced. Calculate the Density. 80 cm3 50 cm3

DENSITY OF AN IRREGULAR SOLID OR use a Eureka Can to find the Volume. Find the mass of the solid on a balance. Add water until just overflowing. Place a Measuring Cylinder under the spout. Add the Object. Collect the Water and read off the Volume. Calculate Density m = 440 g 40.0 cm3  = m = 440 =11.0 g/cm3 V 40

DENSITY OF A GAS Remove the air from a flask of a known Volume, using a vacuum pump. Find its Mass. Add the gas to be tested. Reweigh. The difference is the Mass of gas. Calculate Density. To vacuum flask 150.0 g 170.0 g 1000 cm3 170 -150 = 20.0g  = m = 20 =0.0200 g/cm3 V 1000

Aluminum 3 1 6 2.70 Iron 1.50 0.62 2.62 Brass 0.25 4 8.50 Wood 2 0.40 Material Mass in g Length in cm Width Height Volume in cm3 Density in g/cm3 Aluminum 3 1 6 2.70 Iron 1.50 0.62 2.62 Brass 0.25 4 8.50 Wood 2 0.40 0.50 Slate 0.92 2.20 2.80 Glass 8 .75 11 2.50 Lead 0.05 20 10 11.30 Marble 13.5 5 Wax 97.9 1.25

Material Mass in g Length in cm Width Height Volume in cm3 Density in g/cm3 Aluminum 0.45 3 1 2 6 2.70 Iron 1.50 2.82 0.62 2.62 1.14 Brass 34 16 0.25 4 8.50 Wood 0.40 0.625 .50 0.50 Slate 0.92 0.88 2.20 0.18 2.80 Glass 8 0.39 .75 11 3.2 2.50 Lead 113 0.05 10 20 11.30 Marble 13.5 0.29 5 Wax 97.9 4.40 1.25 8.9

Density as a Function of Temperature For most substances, as temperature increases the volume increases and as a result the density decreases.