The Avogadro Project is an international effort to determine a value for the Avogadro number with a precision approaching 1 part in 108. The principal is:
- Manufacture a sphere of mass one kilogram from a single crystal of high purity silicon.
- Measure the sphere's diameter.
- Measure the atomic spacing in the crystal structure using X-Rays.
- Using this information compute the number of atoms in the sphere.
- Calibrate the sphere against the International Prototype Kilogram
- Use the above information along with the atomic weights of carbon and silicon to calculate the Avogadro number.
The project is also being used along with the Watt Balance Project to redefine the kilogram.