Academic standards correlations on Teachers' Domain use the Achievement Standards Network (ASN) database of state and national standards, provided to NSDL projects courtesy of JES & Co.
We assign reference terms to each statement within a standards document and to each media resource, and correlations are based upon matches of these terms for a given grade band. If a particular standards document of interest to you is not displayed yet, it most likely has not yet been processed by ASN or by Teachers' Domain. We will be adding social studies and arts correlations over the coming year, and also will be increasing the specificity of alignment.
Materials such as metals (aluminum, iron, copper, etc.), ceramics (silicon carbide, porcelain) or polymers (milk jugs made of polyethylene) are tested by scientists and engineers to reveal certain mechanical properties to determine what uses the materials may have. One property that is tested is the amount of stress a material can handle before it breaks. You have probably tested the amount of stress a material can handle before by twisting or pushing on an object such as a toy until it breaks. The amount of stress a material can handle before it breaks measures how strong the material is. Also, as a material gets older, it can handle less stress which can cause it to fail at much lower stresses. For example, if a material is loaded over and over again and then fails it has undergone what is known as fatigue.
Fatigue is a very common mode of failure for materials and has been studied for centuries. Fatigue occurs every day in objects that you’re familiar with. For example, airplane wings fatigue thousands of cycles on every flight and bridges fatigue every time a car drives over them. However, just because a material is undergoing fatigue does not mean that it will always break. In fact, engineers run careful experiments so that they can be sure that things will not break due to fatigue while you are using them.