Related Experiment Video

Updated: Jul 26, 2026

Echo Particle Image Velocimetry
16:31

Echo Particle Image Velocimetry

Published on: December 27, 2012

Effect of internal wall covers on radon emanation inside houses

Health Physics
|March 1, 1983
PubMed

Related Concept Videos

Conduction, Convection and Radiation: Problem Solving01:20

Conduction, Convection and Radiation: Problem Solving

There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
Masonry Cavity Walls01:26

Masonry Cavity Walls

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...
Cavity Drainage and Flashings in Masonry walls01:20

Cavity Drainage and Flashings in Masonry walls

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...
Thermal Insulation in Masonry Walls01:22

Thermal Insulation in Masonry Walls

In hot, dry climates, the thermal mass of masonry walls can be beneficial, absorbing heat during the day and releasing it at night, thereby stabilizing indoor temperatures. However, in most other climates, additional insulation is necessary to enhance thermal resistance.
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh.
Expansion and Contraction in Masonry Walls01:19

Expansion and Contraction in Masonry Walls

Masonry walls are subject to slight expansion and contraction due to variations in temperature and moisture. Thermal movement in masonry is relatively straightforward to measure and plan for. On the other hand, moisture movement poses more of a challenge. New clay masonry units typically absorb water and expand over time under normal environmental conditions. Conversely, new concrete masonry units tend to shrink as they lose the excess moisture acquired during their production process.
To...
Efflorescence in Masonry01:25

Efflorescence in Masonry

Efflorescence in masonry walls appears as a fluffy crystalline powder, often white, resulting from water-soluble salts within the masonry or mortar. When water penetrates the masonry, it dissolves these salts and brings them to the surface, where they are deposited upon evaporation of water.
While initial efflorescence is common post-construction and can be cleaned with water and a brush, in certain instances, efflorescence can reappear and gradually diminish over time as salts are leached out...