You enter to your car, insert the switch and try to start the engine, but the engine won't start. You sit frustrated and don't know what to do. You remember a joke about an electrical engineer a chemical engineer and a software engineer that are driving to a convention. Suddenly the engine stops. The electrical engineer suggests to check the ignition system. The chemical engineer suggests to to check the fuel system. The software engineer suggests to close all the windows, get out of the car, get into the car and open all the windows. This gives you an idea - to check if the problem is in the fuel system or in the ignition system. Check if the fuel reach the engine seems hard, but checking the ignition system seems much easier. You can hear the starter spinning, so the battery should be OK. You check if high voltage is delivered to the plugs by disconnecting one plug's wire and applying ignition while bringing the wires end near the engine house (you have very long hands). If you don't see a spark it means that there is a problem with the ignition system. You turn the ignition key and a spark shows. The problem is probably not with the ignition system, but with the fuel system. There might be a block in the fuel hose. So you open the gas plughole and try to produce a vacuum in the gas tank. Then you try to start the engine. It works fine. You can drive to work.
This car ignition example demonstrates some of the skills that a good engineer should have:
