Adhesion occurs when one type of molecule is attracted to a different molecule. Water exhibits adhesive properties in the presence of polar surfaces, such as glass or cellulose in plants. For instance, when water is poured into a glass, the positively charged hydrogen molecules of water are more attracted to the negatively charged oxygen molecules in the silica than to the oxygen in neighboring water molecules.
Capillary action is a result of water’s adhesive tendencies. When a narrow glass...

During the 1950s, the landmark Robbers Cave experiment demonstrated that when groups must compete with one another, intergroup conflict, hostility, and even violence may result. At the Oklahoman summer camp, two troops of boys—termed the Rattlers and the Eagles—took part in a week-long tournament. During this time, their negativity culminated in derogatory name-calling, fistfights, and even vandalism and destruction of property. However, this work also revealed that such tension could be...

Masonry load-bearing walls, constructed from materials like brick, stone, or concrete masonry units, serve as a crucial component in building structures by supporting the loads from floors and roofs and transferring them to the foundation. These walls, known for their compressive strength, can be reinforced or unreinforced to suit different building needs, accommodating both the dead and live loads while maintaining safety through lower working stresses compared to the materials' ultimate...

Masonry curtain walls employ brick or stone veneers supported by the building's structure to form an external cladding system that is both aesthetically appealing and functional. These walls are erected through two principal techniques, first by traditional layering of masonry units and second by using prefabricated panels. Traditional construction relies on steel shelf angles attached to the spandrel beam for support, with high-bond mortars ensuring secure attachment of masonry veneer units.

Cavity walls feature a hollow space between the outer and inner wythes, connected only by corrosion-resistant metal ties. When water seeps through the outer wythe, it descends within this cavity, intercepted by flashing and eventually exiting through weep holes. To enhance moisture resistance, the inner wythe's cavity side often receives damp-proofing, doubling as an air barrier. The cavity can also house insulation to mitigate heat transfer.
Maintaining a clean cavity during construction is...

Typically, a cavity wall consists of two wythes separated by a gap of at least 2 inches, which may contain insulation while still maintaining a minimum clear space of 1 inch to facilitate adequate drainage. Advanced methods like the insertion of a continuous drainage mat can further reduce this space while ensuring effective moisture expulsion.
Weep holes, strategically placed at the base of the cavity, are critical for draining accumulated water. These openings are created by leaving head...