木公木白

In accordance with the definition of density as  

                                 ρ= m/V,

in order to determine the density of matter, the mass and the volume of the sample must be known.

The determination of mass can be performed directly using a weighing instrument.

The determination of volume generally cannot be performed directly. 

as you know, 

The volume of a liquid can be measured in a graduated cylinder or in a pipette;

The volume of solids can be determined by immersing the sample in a cylinder filled

with water and then measuring the rise in the water level.

Because of the difficulty of determining volume with precision,

especially when the sample has a highly irregular shape when determining the density,

by making use of the Archimedean Principle, which describes the relation between  masses, volumes and densities of solid samples

immersed in liquid:

From everyday experience,

Everyone is familiar with the effect that an object or body appears to be lighter than in air.

That's situation just like your own body in a swimming pool.

W1: weighing in air

W2: weighing in water

  ρ= W1 /(W1 - W2)/ρfl

Sometimes we found that test results are not satisfied.

The reason for the error caused by measurement：

1、Human and Environment error(w1＆W2)：such as incorrect operation, Wind、Magnetic Field、Vibration。

2、Air bubble: According to the technical reports of Sartorius(Germany), the air bubble will cause error value(W2) of water-weight.

• A diameter of 0.5 mm bubble will generate added buoyancy which less than 1mg.
• A diameter of 1mm bubble will generate a 0.5 mg of additional buoyancy.
• A diameter of 2mm bubble will produce about 4.2 mg of added buoyancy
• Big bubbles must be removed by using brush or other tools. The sample can be wetted in another container before weighing

 Our products are designed according to Archimedean principle, and we have manufactured many different kinds of machine

for testing density of different materials, such as:

1. Solid density tester for permeable material 

2. Solid density tester for impermeable material

3. Liquid S.G and concentration tester for chemical solution

4. Precious metal karat, purity, density tester for gold alloys

5. Powder true density tester for powder

6. On-line monitor system for chemical solutions

If you are interested in our new products, please feel free to contact me!

roger560911@gmail.com