1)Weigh the mass (WP) of the solid in a dry pycnometer.
2)Water is added to about 80% of the above pycnometer, and the pores of the solid are degassed in a boiling water bath or a vacuum bottle.
3)After the pycnometer has returned to room temperature, fill the pycnometer with water.
4)Weigh the mass (WPW) by inserting a capillary tube.