Ruler vs pressure

Atmospheric pressure is the force per unit area exerted against a surface by the weight of air above that surface in theEarth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location.

A column of air with one square centimetre in cross-section, measured from sea level to the top of the atmosphere, has a mass of about a kilogram and a weight of 63N. By increasing the surface we increasing the weight applied to the ruler which shows that the atmospheric pressure is significant.