DENSITY Q) Which weighs more:- A kilogram of feathers or a kilogram of iron?
What is Density? Density is the Mass per unit Volume WoodWaterIron 1 cm 3 1 cm 3 1 cm 3 If you take the same volume of different substances, then they will weigh different amounts g1.00 g8.00 g Q) Which has the greatest mass and therefore the most dense? IRON
Density = Mass Volume g or kg cm 3 or mL g/cm 3 or kg/mL D = m V Example: Q) Liquid water has a density of 1000kg/mL, while ice has density of 920kg/mL. Calculate the volume occupied by 0.25kg of each. Density Equation: m VD V = m = 0.25 = mL D 1000 V = m = 0.25 = mL D 920
DENSITY OF A REGULAR SOLID Find the Mass of the solid on a balance. Find the Mass of the solid on a balance. Measure the three lengths and calculate the Volume. Measure the three lengths and calculate the Volume. (ie V = l x w x h ) Calculate the Density. Calculate the Density. 4.0 cm 2.0 cm 3.0 cm D = m = 240 =10.0 g/cm 3 V 24 m = 240 g
DENSITY OF A LIQUID Find the Mass of an empty Measuring Cylinder. Find the Mass of an empty Measuring Cylinder. Add a certain Volume of Liquid. Add a certain Volume of Liquid. Find the Mass of the Measuring Cylinder and Liquid Find the Mass of the Measuring Cylinder and Liquid Calculate the Mass of Liquid. Calculate the Mass of Liquid. How? How? Calculate Density of Liquid. Calculate Density of Liquid. Mass of Liquid = Mass of Measuring Cylinder and Liquid – Mass of empty Measuring Cylinder 25.0 g 20.0 mL 45.0 g 45 – 25 = 20 g D = m = 20 =1.00 g/mL V 20
DENSITY OF AN IRREGULAR SOLID Find the Mass of the solid on a balance. Find the Mass of the solid on a balance. Fill the Measuring Cylinder with Water to a known Volume. Fill the Measuring Cylinder with Water to a known Volume. Add the Object. Add the Object. Work out the Volume of Water that is displaced. Work out the Volume of Water that is displaced. Calculate the Density. Calculate the Density. 50 cm 3 80 cm 3 m = 360 g D = m = 360 =12.0 g/cm 3 V 30
DENSITY g/cm 3 Aluminium2.70 Brass8.50 Iron7.86 Wood0.50 Slate2.80 Glass2.50 Lead11.3 Marble2.70 Wax0.89