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Density 1

Density is defined as the ratio of mass to volume, with units of kg/m3 or g/cm3. The document explains how to measure the density of solids and liquids, including conversion between units, and provides practice questions for understanding density concepts. It also discusses the behavior of materials in relation to their density, such as sinking or floating.

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kamlesh.singh
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44 views19 pages

Density 1

Density is defined as the ratio of mass to volume, with units of kg/m3 or g/cm3. The document explains how to measure the density of solids and liquids, including conversion between units, and provides practice questions for understanding density concepts. It also discusses the behavior of materials in relation to their density, such as sinking or floating.

Uploaded by

kamlesh.singh
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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DENSITY

Density is the ratio of mass to volume.

Density = Mass /Volume


Unit of density = Unit of mass /Unit of volume
= kg / m3 or g / cm3 .
Conversion of unit of density

From kg / m
to g / 3 cm 3 :
Divide by 1000

From g / cm3 to kg / m3 :
Multiply by 1000
..More about density

The material which is more denser will


sink and the material which is less denser
will float.
Practice Questions:

1. A metal block of volume 48 cm3 and has


mass of 96 g. What is its density? Convert
your answer into kg/m3.
2 . A cereal manufacturer creates a new
cereal with a density of 1.25 g/cm3.
She then measures out 75 cm3 of milk
with a mass of 85 grams.
Will the cereal float or sink in the milk ?
Justify your answer.
Measuring the density of an irregularly shaped solid

M = 50g
● VOLUME OF STONE = final volume – initial

volume
= V2 – V1
= (40 – 30 ) cm³
= 10 cm³

V1 = 30 cm³ V2 = 40 cm³
● DENSITY = MASS / VOLUME
● = 50 /10
● = 5 g/ cm³
Initial volume Final volume
Measuring the density of an irregularly shaped solid

1. Mass of solid is found by placing it on top pan balance.

2. The volume is found by pouring water into a measuring


cylinder until it is about half filled.
3. The volume of water is read on the scale and
then solid is carefully lowered into the water and
note the second reading.
4.The volume of a solid is found by subtracting the
first reading from the second i.e ;
( final volume – initial volume )
The density is found by dividing the mass of solid
5.

by its volume.
Measuring the density of a liquid
Measuring the density of liquid

1. A measuring cylinder is put on a top pan balance and


its mass found (A).

2. The liquid is poured into the measuring cylinder and its


volume measured (V).
3. The mass of measuring cylinder and the liquid it
contains is found (B).
4. The mass of the liquid is found by subtracting A from B.

5. The density of the liquid is calculated by dividing the

mass of liquid by its volume.


Practice Questions

1. You find a ring with a mass of 107 g. You fill a


graduated cylinder up with 10 cm3 of water and put the
ring into the cylinder. The water rises up to 15 cm3
mark. What is the density of ring? Convert your answer
into kg/m3 .
2. When full fat milk is poured into a container, the cream
rises to the top. (Justify your answer)
3) A block of material is 23 cm long, 15 cm wide &
10 cm high and has a mass of 4.5 kg. Find its
density.
Materials Density (kg/m3 )
Steel 7900
4. Aluminium 2700
Copper 8940
Cork 250

a) Which is heavier, 1 m3 of steel or 1m3 of aluminium?


b) Which is heavier, 1 kg of copper or 1 kg of cork?

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