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EXPERIMENT 4

AIM

To determine the density of a stone (a non-porous solid of irregular shape)

BASIC THEORY

The density of a material is defined as its massper unit volume:

Different materials usually have different densities, so density is an important

concept regardingbuoyancy, metal purity and packaging.

In some cases density is expressed as the dimensionless quantities specific

gravity orrelative density, in which case it is expressed in multiples of the density of

some other standard material, usually water or air.

For a homogeneous object, the mass divided by the volume gives the density.

The mass is normally measured with an appropriate scale or balance; the volume may

be measured directly (from the geometry of the object) or by the displacement of a

fluid.

If the body is inhomogeneous, the density is a function of the coordinates

, where dv is elementary volume with coordinates . The mass of

the body then can be expressed as

,

where the integration is over the volume of the body V.

A very common instrument for the direct measurement of the density of a

liquid is the hydrometer, which measures the volume displaced by an object of known

mass. A common laboratory device for measuring fluid density is apycnometer; a

related device for measuring the absolute density of a solid is a gas pycnometer.

Another instrument used to determine the density of a liquid or a gas is the digital

density meter - based on the oscillating U-tubeprinciple.

http://en.wikipedia.org/wiki/Masshttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Buoyancyhttp://en.wikipedia.org/wiki/Packaginghttp://en.wikipedia.org/wiki/Dimensionlesshttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Relative_densityhttp://en.wikipedia.org/wiki/Homogeneoushttp://en.wikipedia.org/wiki/Weighing_scalehttp://en.wikipedia.org/wiki/Hydrometerhttp://en.wikipedia.org/wiki/Pycnometerhttp://en.wikipedia.org/wiki/Gas_pycnometerhttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Oscillating_U-tubehttp://en.wikipedia.org/wiki/Masshttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Buoyancyhttp://en.wikipedia.org/wiki/Packaginghttp://en.wikipedia.org/wiki/Dimensionlesshttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Relative_densityhttp://en.wikipedia.org/wiki/Homogeneoushttp://en.wikipedia.org/wiki/Weighing_scalehttp://en.wikipedia.org/wiki/Hydrometerhttp://en.wikipedia.org/wiki/Pycnometerhttp://en.wikipedia.org/wiki/Gas_pycnometerhttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Oscillating_U-tube

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The density of a solid material can be ambiguous, depending on exactly how

its volume is defined, and this may cause confusion in measurement. A commonexample is sand: if gently filled into a container, the density will be low; when the

same sand is compacted into the same container, it will occupy less volume and

consequently exhibit a greater density. This is because sand, like all powders and

granular solids contains a lot of air space in between individual grains; this overall

density is called thebulk density, which differs significantly from the density of an

individual grain of sand.

APPARATUS

A piece of stone

Measuring cylinder

Water

Thread

Balance

PROCEDURE

1. Weight the stone to determine its mass (m)

2. Pour water into the measuring cylinder to about one-third of its depth.

Record the volume of water in the measuring cylinder, V1 in cm3.

3. Attach the piece of stone to a piece of thread about 50 cm long andlower the stone gently into the water. Record the volume of the water

plus the stone in the measuring cylinder, V2 in cm3.

4. Empty the cylinder, dry the stone and repeat the experiment twice

using slightly different value of V1.

RESULTS

Mass, (m) = 50,69 g

V1 in cm3 V2 in cm

3 Volume of stone = (V1 - V2) in cm3

1st attempt 50 cm3 59 cm3 9 cm3

2nd attempt 60 cm3 68 cm3 8 cm3

3rd attempt 80 cm3 87 cm3 7 cm3

Average volume of stone 8 cm3

Density of stone = mass = 50,699 g = 6,33 g/cm3

Volume 8 cm3

http://en.wikipedia.org/wiki/Bulk_densityhttp://en.wikipedia.org/wiki/Bulk_density

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CONCLUSION

The density of stone = 6,33 g/cm3

QUESTIONS

1. Explain why it is not possible to use the experiment to determine the density

of cork.

Because the cork absorb the water and float in the water, so that is cant be

determine the density.

2. How should the experiment be modified such that density of cork be

determined?

Asessor: The experimenters :

IL Rahma Pradira Gesari / X-5/ 13

Inayah Nur Utami / X-5/ 14

Khairina Izzati Amalia / X-5/ 15

Konita Septiasti / X-5/ 16