People usually say ‘short circuit’ to mean any sort of electrical problem, but it’s actually more specific than that. Suppose you have a light bulb connected to a battery. If the light is ‘on’, there’s electricity flowing – coming out of the battery, going through the light bulb and then back into the battery. This is a circuit. A short circuit is when electricity doesn’t take the path it was meant to – for example, if two bare wires touch. This causes a lot of electricity to surge at that point of contact, which causes the wires to get very hot.