Presentation on theme: "DENSITY Q) Which weighs more:-"— Presentation transcript:
1 DENSITY Q) Which weighs more:- A kilogram of feathers or a kilogram of iron?DENSITY
2 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.WoodWaterIron1 cm31 cm31 cm3IRON0.50 g1.00 g8.00 gQ) Which has the greatest mass and therefore the most dense?Density is the Mass per unit Volume
4 Cube Representations 1 m3 = 1 000 000 cm3 Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 119
5 Density Equation: d = m V Mass Density = Volume Example: gMassDensity =Volumeg/cm3cm3d = mVExample:Q) A gold-colored ring has a mass of 18.9 grams and a volume of 1.12 cm3. Is the ring pure gold? (The density of gold is 19.3 g/ cm3.)d = m = 18.9g = g/cm3V cm3No – it is not pure gold!
6 DENSITY OF A REGULAR SOLID Find the Mass of the solid on a balance.Measure the three lengths and calculate the Volume.(i.e., V = l x w x h )Calculate the Density.m = 240 g2.0 cmd = m = 240 =10.0 g/cm3V(2cm * 3cm * 4cm = 24 cm3)3.0 cm4.0 cm
7 DENSITY OF AN IRREGULAR SOLID m = 360 gd = m = 360 =12.0 g/cm3VFind 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 cm350 cm3
8 it floats What happens when you put an object in a fluid? If the object is less dense than the fluid…it floats
9 it sinks! What happens when you put an object in a fluid? If the object is more dense than the fluid…it sinks!
10 Neither floats nor sinks! What happens when you put an object in a fluid?If the object is as dense as the fluid…Neither floats nor sinks!