Encyclopaedia

Weight

The term weight is often used in everyday language as if it were the same as mass. Physically, however, weight refers to the force with which a body is attracted due to gravity. The mass of a body remains the same regardless of location, while the weight force depends on the local gravitational acceleration.

On Earth, gravitational acceleration acts on a body with mass. This creates the weight force. In science and technology, it is important to distinguish between mass and weight force.

• Mass: fundamental property of a body and a measure of its inertia grundlegende Eigenschaft eines Körpers und Maß für seine Trägheit
• Weight force: force acting on a body due to gravity
• Unit of mass: kilogram kg
• Unit of force: newton N

Air Density

Air density indicates the mass of air contained in a certain volume. It depends, among other things, on temperature, air pressure, humidity and altitude above sea level.

In precise mass determination, air density plays an important role because air buoyancy influences the measurement result. For this reason, environmental conditions are recorded and taken into account in high-precision calibrations.

Calibration

During a calibration, the deviation of a measured value from a traceable standard is determined and documented. Under defined conditions, the measured value of a measuring instrument or test equipment is compared with the known value of a standard.

Calibration is not an intervention in the measuring instrument or test equipment. The measuring instrument remains unchanged. The result is documented in a calibration certificate, for example with deviation, measurement uncertainty and traceability.

Recalibration

Recalibration is the repeated calibration of test equipment after a specified or application-related interval. It is used to assess the current condition of a test weight or weight set and to document its continued usability.

For test weights, recalibration can determine whether the weight still meets the requirements of the specified accuracy class. If technically possible and necessary, adjustment may be carried out beforehand.

Permeability Measurement

Magnetic permeability describes how strongly a material reacts to an external magnetic field. It is a measure of how easily a material can be magnetized or influence magnetic fields.

For high-precision test weights, magnetic properties are particularly important. Depending on the accuracy class and requirements, permeability, magnetic susceptibility or polarization are therefore tested and evaluated.

Adjustment

Adjustment means setting or aligning a measuring instrument or test equipment in order to reduce or eliminate a deviation. Unlike calibration, adjustment is an intervention that changes the measuring instrument or test equipment.

For test weights, adjustment may be necessary if the measured deviation is outside the permissible error limits and the weight is technically adjustable. After adjustment, recalibration should be carried out.