Definition, Symbol, SI Units, Formula & Measurement of Density
Density is simply mass per unit volume. Density of many samples is measured in labs for example in oil and gas industry. They define density in general way as 'weight per unit volume' although 'weight per unit volume' is not density it is 'Specific Weight' so density is 'mass per unit volume'.
Example of Density
Don't worry! we will going to learning density in very simple way, with examples.
Do you ever see a dry WOOD piece floating over water in river or pool?
Yes, We all see that, Do you think why it floats. Because density of wood ๐ชต is lesser than density of water ๐ง so piece of ๐ชต wood experience upthrust force and float on water ๐ง.
Take another example of Iron Metal piece and water. IRON METAL piece has higher density than WATER, so piece of iron metal sink in water.
To understand clearly, we will take another example of 'Sunflower Cooking oil' & 'Water'. When we mix 'Sunflower Cooking oil' & 'Water', after some time oil comes at top and water set below (means separate out). So now question is why this happens? Answer is due to difference in density & nature of water and oil. Oil is nonpolar while water is polar molecule so they don’t interact with each other.
Density of Sunflower Cooking oil is 919 Kg/m3
Density of Water is 1000 kg/m3
What is Density in Chemistry
In science/chemistry, density of a substance is its mass per unit volume. Density is also known as "Volumetric Mass Density".
Generally different materials have different density. Chemical element Osmium (Os having atomic number 76) is naturally occurring densest element. To simplify the comparison of densities of different materials or liquids it is needed to replace density with "relative density" as relative density is dimensionless quantity. Relative Density is also called "Specific Gravity".
Specific gravity or relative density is the ratio of density of sample material to the density of standard material. Generally water is taken as standard material. If we take water as standard material than if we get relative density of a material is less than '1' means that material floats in water. Water has highest density at 4 °C i.e. 1000Kg/m3.
Density of material depends on the temperature and pressure. Effect of temperature and pressure is very less on solid and liquid but effect of temperature and pressure is very high on gases. If we increase pressure on given material than its volume get decrease that result in increase in density, similarly If we decrease pressure on given material than its volume get increase that result in decrease in density.
And in case of temperature, if we increase temperature on given material than its volume get increase that result in decrease in density, similarly if we decrease temperature on given material than its volume get decrease that result in increase in density.
But their are some exceptions which do not follow these rules, one of them is water means when temperature of water decreases than it makes solid ice which float on liquid water as ice have less density than liquid water i.e. Density of ice is 916.7 Kg/m3 at 0 °C, and water has a density of 999.8 Kg/m³ at 0 °C.
Definition of Density
Density of a material is defined as its mass per unit volume.
Symbol of Density
Symbol of density is 'ฯ' or 'D' and pronounces as 'rho'.
Formula of Density
Density = Mass/Volume
or,
ฯ = m/V
where,
ฯ is density, m is mass and V is volume.
- When numerator (mass) is much larger than denominator (volume) in density formula, that shows the given substance has higher density, but when denominator (volume) is much larger than the numerator (mass), that shows the given substance has lower density.
SI Unit of Density
SI Unit of Density is Kg/m3 or g/cm3
Density Calculator
Density is calculated by dividing mass by volume. Density is measured as units of mass/volume, often g/cm3, g/Kg3 or g/mL. Just enter value of mass and volume to get density.
Instruments used to measure Density
Weighing balance, Scale, Hydrometer and Thermometer are some instruments used to measure the density of solids & liquids.
Measurement
How to Measure Density of a Solid
Just watch below video to learn how to measure density of a solid.
 |
| Hydrometer |
 |
| Hydrometer dip in mineral oil and engine oil to measure the Density of these samples |
Density Chart |
||
Material
|
Density (Kg/m3)
|
Remark
|
Air
|
1.2
|
At sea level
|
Milk
|
1027 to 1033
|
At 20 oC
|
Honey
|
1420
|
At 20 oC
|
Coconut Oil
|
925
|
At 15 oC
|
Cotton Seed Oil
|
926
|
At 16 oC
|
Olive Oil
|
918
|
At 15 oC
|
Sunflower Oil
|
919
|
At 20 oC
|
Rice Bran Oil
|
918
|
At 20 oC
|
Groundnut Oil
|
913
|
At 20 oC
|
Liquid Hydrogen
|
70
|
At about -255 oC
|
Ice
|
916.7
|
At 0 oC
|
Fresh Water
|
1000
|
At 4 oC
|
Plastics
|
1175
|
Approx for PVC
|
Glycerol
|
1261
|
Also called Glycerine or Glycerin
|
Aluminium
|
2700
|
Chief ore of Aluminium is Bauxite
|
Diamond
|
3500
|
Precious stone
|
Zinc
|
7000
|
Zinc
is found in cells throughout the body.
|
Iron
|
7870
|
Used since ancient times
|
Cobalt
|
8900
|
Found
in the Earth's crust only in chemically combined form
|
Nickel
|
8900
|
Silvery-white lustrous metal
|
copper
|
8940
|
Very high thermal and electrical
conductivity
|
Silver
|
10500
|
Highest electrical conductivity, thermal
conductivity
|
Lead
|
11340
|
Soft, malleable, and heavy metal
|
Mercury
|
13546
|
Only metallic element that is
liquid at room temperature
|
Uranium
|
18800
|
weakly radioactive because all its
isotopes are unstable
|
Iridium
|
22420
|
Densest naturally occurring element
|
Osmium
|
22570
|
Densest naturally occurring element
|
Thank for reading!
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1 comment:
1. Surface Tension (Capillary action - Capillary tube)
2. Consistency
3. Viscosity
4. Contact Angle
5. Density
6. Fash point
Surface Tension - Tensiometers are used, which calculate the force needed to break through the liquid surface.
Consistency - A pile of the sample is enclosed in a container of fixed volume. The container is opened and the time measured for gravity to pull the sample a fixed distance. This instrument is called a Consistometer.
Viscosity - The measurement of the friction between the molecules in a flowing liquid is measured by an instrument class known as Viscometers.
Contact Angle - Contact Angle Instruments measure the angle between a drop and the surface of the substrate. They are sometimes known as goniometers.
Density - Density is measured by comparing the weight of a volume of the test sample with the weight of the same volume of a standard liquid.
Color, Odour, taste, Solubility, Melting point & Boiling point, specific heat, thermal conductivity, surface tension, dipole moment, Vapour presure, Refractive index, density, temperature, humidity, viscosity, dynamic viscosity, kinematic viscosity, acidity pKa & Basicity pKb, Thermal conductivity, Crystal structure, Molecular shape, Point group, dipole moment, specific heat capacity, std enthalpy of formation, std molar entropy, gibbs free energy.
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