Surface tension is the cohesive force found between molecules that are liquid in nature. This cohesiveness forms a level of resistance at the surface of the liquid that is not present in the same degree beneath the surfa... More » Science Physics

Liquids evaporate into the air when their molecules gain enough energy to break free of the liquid’s surface tension and become a gas. As this happens only at the surface, or liquid-air interface, the amount of surface a... More »

Pressure outside the straw pushes against the water inside the straw and prevents it from dropping, according to University of California, Santa Barbara. The outside pressure has to sustainably overcome gravity to preven... More » Science Physics Motion & Mechanics

Surface tension is caused by the attraction between liquid molecules along the surface of the liquid. Most of the molecules in a liquid have several neighboring molecules that they interact with, but the molecules along ... More » Science Physics Motion & Mechanics

When a force is applied to an object resting on a surface, a retarding force is that which opposes the force being applied to the object. A retarding force is usually that of friction, which must be overcome when moving ... More »

To calculate the normal force on an object, draw a free body diagram, determine the surface's angle, factor in the other present forces, and solve for the normal force. Note that the normal force is perpendicular to the ... More »

The forces that attract water molecules to one another cause surface tension. Water molecules can form hydrogen bonds with each other, and each molecule is attracted to those around it. Molecules at the surface are more ... More »