" Their predicted properties were experimentally confirmed with good precision. The Large Electron-Positron collider at CERN tested various predictions about the decay of Z bosons, and found them confirmed . To get an idea of the success of the Standard Model a comparison between the measured and the predicted values of some quantities are shown in the following table: Quality Measured (GeV) SM prediction (GeV) Mass of W boson 80,4120±0,0420 80,3900±0,0180 Mass of Z boson 91,1874±0,0021 91,1874±0,0021 Challenges to the Standard Model Although the Standard Model has had great success in explaining experimental results, it has never been accepted as a complete theory of fundamental physics. This is because it has two important defects: The model contains 19 free parameters, such as particle masses, which must be determined experimentally (plus another 10 for neutrino masses). These parameters cannot be independently calculated. The model does not describe the gravitational interaction. Since the completion of the Standard Model, many efforts have been made to address these problems. Boat Handcrafted Model One attempt to address the first defect is known as grand unification. The so-called grand unified theories (GUTs) hypothesized that the SU(3), SU(2), and U(1) groups are actually subgroups of a single large symmetry group. "

" The Model T was the first automobile mass produced on assembly lines with completely interchangeable parts, marketed to the middle class. To speed assembly, between 1915 and 1925 it was only available in one color, black. Black paint was also cheaper and more durable. Henry Ford is reputed to have made the statement "Any customer can have a car painted any color that he wants so long as it is black. " Model Ts in different colors were produced from 1908 to 1914, and then again from 1926 to 1927. By 1914, the assembly process for the Model T had been so streamlined it took only 93 minutes to assemble a car. That year Ford produced more cars than all other automakers combined. Boat Model Shrimp The Model T was a great commercial success, and for years in the late 1910s and early 1920s it was estimated that more than half of all motorcars in existence in the world were Model T Fords. In fact, it was so successful that Ford did not purchase any advertising between 1917 and 1923; in total, more than 15 million Model Ts were manufactured, more than any other model of automobile for almost a century. "