In reading assignment 5 ( Material & Properties / Ching ; 12.04 ~ 12.12 ) We explore the strengths and weakness of five fundamental building materials. the materials discussed are Stone, Brick/CMU, wood, steel and concrete. Following the reading order, we start off with the properties of stone; stone can be comprised of different compact minerals and inorganic matter, its compressibility is fairly high compared to its shear strength, being only 1/10 of its strength. This is why stone works very well when using it as load bearing walls.  these stones can be broken down into five categories; Hardness, Durability, work-ability, density and appearance. these characteristics of the stone determines how it should be used in a particular project. There  are three types of rock formation – Igneous , Metamorphic rock and sedimentary with some familiar names such as granite, marble and limestone falling under one of those classifications respectively. Next comes Masonry, which refers to brick, stone or concrete block. Brick which is defined by Chang as “a masonry unit of clay, formed into a rectangular prism ~ hardened by firing in a kiln” has different classification, which are determined by its moisture content, two types of brick  are called “common brick” and “face brick”.  these bricks come in different grades according to its resilience against  weather; classifications are NW, MW, and SW , with higher weather tolerance going from left to  right. concrete masonry which are precast of Portland cement are broken down into two groups; Grade N – load bearing concrete 800 to 1500 psi and  Grade S load bearing concrete 600 to 1000 psi and no moisture. The next material to discuss is wood; Wood can be broken down into two classes, Soft wood and hard wood. some examples of soft wood is ever green, pine and hemlock which can be used in general construction. some exampled of hardwood would be cherry maple and oak which can be used as decorative floor paneling. wood generally has 1/3 more of its force if  cut parallel to its grain. but steel which is the following construction material is the best of all worlds, steel has a compression and shear strength of about 50,000 psi and is defined by having a carbon content less than that of cast iron,  more than raw iron and is heat treated. steel can become hard or soft depending on the carbon content within the alloy. steel becomes ductile at approximately 1000 degrees Fahrenheit, making it necessary to coat it with anti corrosion and heat material.  the last material concrete is made from various minerals but can primary be broken down by its clay to limestone mixture. The Law D.A Abrams states that  Comprehensive strength of concrete is inversely proportional to the ratio of water to cement. A cement mixture with a water ratio approximately 0.45 ~ 0.60 can fully cure and harden after 28 days, with the 7th day allowing for early strength concrete.