Editing Drop (liquid) (section)

== Drop adhesion to a solid ==
The drop [[adhesion]] to a solid can be divided into two categories: lateral adhesion and normal adhesion. Lateral adhesion resembles friction (though [[tribology|tribologically]] lateral adhesion is a more accurate term) and refers to the force required to slide a drop on the surface, namely the force to detach the drop from its position on the surface only to translate it to another position on the surface. Normal adhesion is the adhesion required to detach a drop from the surface in the normal direction, namely the force to cause the drop to fly off from the surface. The measurement of both adhesion forms can be done with the Centrifugal Adhesion Balance (CAB). The CAB uses a combination of centrifugal and gravitational forces to obtain any ratio of lateral and normal forces. For example, it can apply a [[normal force]] at zero lateral force for the drop to fly off away from the surface in the normal direction or it can induce a lateral force at zero normal force (simulating zero [[gravity]]).