density. volume the volume of an object is the amount of space it takes up the si unit of volume is...
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Density
Volume
• The volume of an object is the amount of space it takes up
• The SI unit of volume is the cubic metre (m3) or cubic centimetre (cm3). The Litre is also used (1L = 1000cm3)
• Graduated Cylinders, burettes, & pipettes are used to measure the volume of a liquid
Measuring the Volume of a Liquid
50
40
30
20
10
0
Burette
Pipette
Graduated Cylinders
• The volume of a liquid is read from the lowest part of the Meniscus (curve)
Measuring the Volume of a Liquid
• The volume of regular solids e.g. cubes, can be found by simply measuring their length, width, & height and using the formula
Measuring the Volume of a Solid
Volume = Length x Width x Height
Remember…….
• 1m3 = 1m x 1m x 1m
• 1m3 = 100cm x 100cm x 100cm
• 1m3 = 1,000,000 cm3
Measuring the Volume of a Solid
• A displacement can and a graduated cylinder is used to find the volume of a solid with an irregular shape
Mass
• The mass of an object is the amount of matter in it
Density
•The density of a substance is its mass per unit volume
•Density = Mass/Volume
Density = Mass Volume
D = M/V
M
D V
Measured in kilograms per metre cubed (kg/m3)
Also g/cm3
Density
DENSITY
Mandatory Experiment
Density of a Solid Rectangular Block
Desity of a irregular Solid
Density of a Liquid
What is Density?
Density is the Mass per unit Volume
Wood Water Iron
1 cm3 1 cm3 1 cm3
If you take the same volume of different substances, then they can have different
masses
0.50 g 1.00 g 8.00 g
Q) Which has the greatest mass and therefore the most dense?
IRON
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.4.0 cm
2.0 cm
3.0 cm
= m = 240 =10.0 g/cm3
V 24
m = 240 g
MateriaMateriall
MassMass
in gin gLengthLength
in cmin cmWidthWidth
in cmin cmHeight Height
in cmin cmVolumeVolume
in cmin cm33
DensityDensity
in in g/cmg/cm33
DENSITYDENSITY g/cmg/cm33
AluminiumAluminium 2.702.70
BrassBrass 8.508.50
IronIron 7.867.86
WoodWood 0.500.50
SlateSlate 2.802.80
GlassGlass 2.502.50
LeadLead 11.311.3
MarbleMarble 2.702.70
WaxWax 0.890.89
DENSITY OF AN IRREGULAR SOLID
Find the Mass of the solid Find the Mass of the solid on a balance.on a balance.Fill the Measuring Cylinder Fill the Measuring Cylinder with Water to a known with Water to a known Volume.Volume. Add the Object.Add the Object. Work out the Volume of Work out the Volume of Water that is displaced.Water that is displaced. Calculate the Density.Calculate the Density.
50 cm3
80 cm3
m = 360 g = m = 360 =12.0 g/cm3
V 30
DENSITY OF AN IRREGULAR SOLID
• OR use a Eureka Can to find the Volume. Find the mass of the solid on Find the mass of the solid on a balance.a balance.Add water until just Add water until just overflowing.overflowing. Place a Measuring Cylinder Place a Measuring Cylinder under the spout.under the spout. Add the Object.Add the Object. Collect the Water and read off Collect the Water and read off the Volume.the Volume.Calculate DensityCalculate Density
m = 440 g
40.0 cm3
= m = 440 =11.0 g/cm3 V 40
DENSITYDENSITY g/cmg/cm33
AluminiumAluminium 2.702.70
IronIron 7.867.86
BrassBrass 8.508.50
WoodWood 0.500.50
SlateSlate 2.902.90
GlassGlass 2.502.50
DENSITY OF A LIQUID• Find the Mass of an empty
Measuring Cylinder.• Add a certain Volume of Liquid.• Find the Mass of the Measuring
Cylinder and Liquid• Calculate the Mass of Liquid.• How?• Calculate Density of Liquid.
Mass of Liquid = Mass of Measuring Cylinder and Liquid – Mass of
empty Measuring Cylinder
25.0 g
20.0 cm3
45.0 g
45 – 25 = 20 g = m = 20 =1.00 g/cm3 V 20
LiquidLiquid Mass of Mass of empty empty
MeasurinMeasuring g
CylinderCylinder
in gin g
Mass of Mass of MeasurinMeasurin
g g Cylinder Cylinder
and and LiquidLiquid
in gin g
Mass of Mass of LiquidLiquid
in gin g
VolumeVolume
in cmin cm33
DensityDensity
in g/cmin g/cm33
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
1000 cm3
150.0 g170.0 g
= m = 20 =0.0200 g/cm3 V 1000
170 -150 = 20.0g
Flotation
Flotation
• An object will float if it is less dense than the liquid
• An object will sink if it is more dense than the liquid
• One liquid can float on top of another e.g oil floats on water
Density is the amount of mass in a particular volume
Density =
g/ cm3
Mass (g)
Volume (cm3)
A B
Diagram B shows a greater density than diagram A because there is more mass in the same volume.
If a substance is more dense than water then it will sink
If a substance is less dense than water then it will float
Dancing Raisins
• http://www.youtube.com/watch?v=tx4x6Qsyr4o
Experiment with the coke and diet coke
• http://www.youtube.com/watch?v=N8DV_B4GJ48
• Mythbusters• http://www.youtube.com/watch?
v=I_F2pTvJfUs
Your Task
• Design an experiment that effects the density of your object .
• You have to make objects float that usually sink
• Remember salt has particles!.
Can I Make an object Sink?
• If an object originally floats can I make it sink?• http://www.youtube.com/watch?v=hp9d7G-
vU_o&feature=related
Homework
• Workbook Pg 134 Q8 9 10• Workbook Pg 135 Q 9 10
Q
• Why does one balloon float and the other Sinks?
Explain why this man floats in the dead sea?
Homework
• Pg 248 of text book • Q 1,2,4,6,7,8
• Density Experiment