Finding the Volume and Density of an Object Using Displacement



Finding the Volume and Density of an Object Using Displacement

Problem: Determine the Density of an object without knowing it’s linear

dimensions.

Materials: Graduated cylinder, water, mass scale, string.

Procedure:

1. Select and weigh an object and record this measurement. Hint: Choose an object that will not float. This will help make the exercise easier.

2. Fill a finely graduated cylinder ½ full with water. Record the water level. This is water level A. Be certain that the cylinder is large enough to accommodate the object

3. Tie a string to the object and immerse it fully in a beaker of water. As the object is immersed into the water, the water level will begin to rise. Record the water level after the object is fully immersed. This is water level B.

4. Subtract water level A from water level B. The volume of the object is equal to the difference in water volume. This can be expressed by this simple statement; Object volume = B-A

5. The Density of the object is a function of the object’s weight divided by the objects volume. This can be expressed by this simple statement; Density = Wgt/Volume. Note: Use either metric units or standard units. Do not mix units!

The term specific gravity, symbolized sp gr, refers to the ratio of the density of a solid or liquid to the density of water at 4 degrees Celsius (39.19 F). Specific gravity is a dimensionless quantity; that is, it is not expressed in units.

Water has a specific gravity of 1. By comparing the density of pure water to the known density of an object we can determine the object’s specific gravity. Another way to understand specific gravity is that it is expressed as a multiple of the density of water.

Example: The density of water is 1 gram/ cubic centimeter or 1000 kg per cubic meter.

If an object has specific gravity of more than 1, it is more dense than water.

A substances with a specific gravity more than 1 are more dense than water, and will sink.

Materials with a specific gravity less than 1 are less dense than water, and will float.

An object with a density of 50 kg/m3 has a specific gravity of 0.050 (50 kg/m3 / 1000 = specific gravity of 0.050.) and will float high on the surface of a body of water because the object is 20 times less dense than water ( 1/0.050 = 20) An object with a density of 85 g/cm3 has a specific gravity of 85 (85 g/cm3 /1 = specific gravity of 85 (85 times more dense than water) and will sink quickly.

Calculate the specific gravity of the object you tested. Use this formula.

Specific gravity = Object density in grams/cubic centimeter/ 1

or

Specific gravity = Object density in Kg/cubic meter/ 1000

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download