An Empty Flask is Full of Air

Problem The term empty flask may mean to the naked eye that neither a liquid nor a solid are present, but we know on the other hand that the flask is really filled with air. So one can pump out the entire air from a flask in this case the flask contains nothing . In order to reflect upon the empty flask , the following small experiments are carried out. 

Material Beaker (200 ml), large glass bowl, syringe with stop cock, glass tube. 

Observation The water remains in the beaker. The water-filled beaker takes 100 ml of air from the syringe, then the air can be sucked back into the syringe again air is a substance with a specific density (see E3.13), a special mass of air takes a special volume at normal pressure. 

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