Life without electricity is something that is no longer imaginable. Whether it be a smartphone, hair-dryer or a ceiling lamp—the technical accomplishments we hold dear all require electricity. Although every child at school learns that electricity can only flow in a closed electric circuit, what is actually the difference between current and voltage? Why is a plug socket a potential death-trap but a simple battery is not? And why does a lamp connected to a power strip not become dimmer when a second lamp is plugged in?