Impetus describes the kind of force that encourages an action (the impetus behind the project) or the momentum of an action already begun (the meetings only gave impetus to the rumors of a merger).
Materials Needed: The box from the last experiment; a ruler that measures centimeters. Procedure: Measure each side of the box in centimeters. Use the formula for the volume of a box shaped object (V = L x W x H ) to calculate the volume of this box in cubic centimeters. What Happened: Each side was 10 cm long. When you plug the numbers into the formula and do the math, you get:
Of course, as more air is removed, the pressure differential increases, and the potential vacuum force becomes greater. The vacuum level is determined by the pressure differential between the evacuated volume and the surrounding atmosphere. Several units of measure can be used. Most refer to the height of a column of mercury â usually inches of mercury (in.-Hg) or millimeters of mercury (mm-Hg). The common metric unit for vacuum measurement is the millibar, or mbar. Other pressure units sometimes used to express vacuum include the interrelated units of atmospheres, torr, and microns.