What an electric shock is
Everything in this chapter now pays off in one place: understanding why electricity is dangerous, and — just as usefully — why sometimes it is not.
Beyond the syllabus — staying safe with electricity
This section is not examined, but it is the part of the chapter most likely to matter to you outside a classroom.
Electric shock
An electric shock occurs when a flow of electrons takes place through the human body.
It needs the same two things as any current
Nothing special applies to a person. For a current to arise, both of these must be present — exactly as they must be in a circuit made of wire.
A closed circuit
There must be a complete path, so the charge has somewhere to enter and somewhere to leave.
A potential difference
The two points where it enters and leaves must be at different potentials, or nothing is pushed.
Two points, not one
Where there are not two places on the body for the current to enter and to leave, there is no risk of a shock. That single sentence explains both of the pictures on the next two pages.