Final answer:
Symbols and schematics are used to represent pipe fittings and electrical fixtures in engineering. The water flow analogy helps to conceptualize electrical circuits, though there are differences between electrons in wires and water in pipes. Incandescent light bulbs are partially evacuated to prolong the lifespan of the filament.
Step-by-step explanation:
In engineering, symbols and schematics are often used to represent pipe fittings and electrical fixtures. For example, in plumbing, drawings might include symbols that represent water pipes, Gas & Fire Pipelines, while in electrical engineering, diagrams would show the layout for Electrical & Communications conduit. These graphical representations help professionals understand where to install components and how they should be connected within a system.
Comparing the flow of electrons in a wire to water flowing through a pipe is a common analogy in understanding electrical circuits. This model helps to conceptualize the behavior of electricity. Electrons moving through wires can be parallel to water molecules moving through pipes, but there are significant differences, such as the fact that electrons are much smaller and the interactions between them are dictated by electromagnetic forces, not just physical collisions.
Regarding incandescent light bulbs, they are partially evacuated -- meaning some air is removed from the bulb -- to reduce the oxidation and subsequent burning out of the filament, allowing the bulb to function properly and last longer.