Density

By Aditi Atmasidha

Density of a substance is a measure of the amount of

matter that is present in a certain volume of it. Density = mass/volume The SI unit of density is kg/cu. m { Cubic Meter } Higher the density the substance or the material is

heavier. The density of water is take as 1 kg per cu. m or 1

gram/ cc { Cubic centimeter } The substances whose density is higher than water

sink in water, while those who have low density than water floats on water.

What is Density?

DensityFormula & Example

Low density: Crude oil, edible oil, Cotton,

Cork , etc.. High density: Stone, Copper, Sea water, Lead.

Examples

To measure the Density of rectangular solid

block: Check the top-pan balance, if it reads zero. Keep the block on top- pan balance and read

the scale, record the mass in grams. Find the volume of block by formula: v =

{ l*b*h }, record the volume in cubic centimeter, followed by Density.

Experiments

Determine the density of irregular solid

{ Pebbles } Find the mass of empty cylinder { m1 }. Pour

water up to volume { v1 } and find it’s mass. Mass of water = m = m2 – m1. Find the volume of pebble v = v2 – v1. { slide

no. 7 }.

Experiments

Experiments

Liquid Density { Kg/m.cu }

Mercury 13550

Water at 4 degree Celsius 1000

Corn oil 900

Turpentine 860

Paraffin oil 800

Methylated spirits 790

Density of Some Liquids

To measure the density of air: http://

www.youtube.com/watch?v=n0zEDSapU4M

Density of Some Gases

Gas Density/ kg/ m.cu

Hydrogen 0.089

Air 1.29

Oxygen 1.43

Carbon dioxide 1.98

Density of gases change as its pressure and

temperature change. The Density of gases are compared by measuring

them at the same temperature and pressure. This is called the standard temperature and pressure. The standard temperature is 0 degree Celsius.

The standard pressure of a gas is the pressure that will support 760 mm of mercury in a vertical tube.

When two gases meet the less dense gas rises above the denser gas.

Density of Some Gases

Floating & Sinking

Floating

Density of a substance is less than Density of solvent.

Substance is less dense than solvent.

Example – wood floating on water

Sinking

Density of substance is greater than Density of solvent.

Substance is more dense than solvent.

Metal coin sinks in the water.

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