" Operation In broad terms, constructing an application using an MVC architecture involves defining three classes of modules. Model: This is the domain-specific representation of the information on which the application operates . The model is another name for the domain layer. Domain logic adds meaning to raw data e. g. calculating if today is the user's birthday or the totals, taxes and shipping charges for shopping cart items. View: This renders the model into a form suitable for interaction, typically a user interface element. Free 3d Paper Airplane Model MVC is often seen in web apps: the view is the html page and the code which gathers dynamic data for the page. Controller: This responds to events, typically user actions, and invokes changes on the model (but *not* the view). "

" The reason for arranging them in generations is that the four fermions in each generation behave almost exactly like their counterparts in the other generations; the only difference is in their masses. For example, the electron and the muon both have half-integer spin and unit electric charge, but the muon is about 200 times more massive. The electron and the electron-neutrino, and their counterparts in the other generations, are called "leptons", "weakly interacting particles". Unlike the quarks, they do not possess a quality called "color", and their interactions are only weak and electromagnetic, and fall off with distance. On the other hand, the strong or "color" force between quarks gets stronger with distance, so that quarks are always found in colorless combinations called hadrons, a phenomenon known as quark confinement. These are either fermionic baryons composed of three quarks (the proton and neutron being the most familiar example) or bosonic mesons composed of a quark-antiquark pair (such as pions). The mass of such aggregates exceeds that of the components due to their binding energy. Model Airplane Building Tests and predictions The Standard Model predicted the existence of W and Z bosons, the gluon, the top quark and the charm quark before these particles had been observed. Their predicted properties were experimentally confirmed with good precision. "