Ask Mr Brain...all will be explained

Does electricity really travel at the speed of light? It is a common misconception that electricity or, to be more accurate, electric current flows at the speed of light. Electric current is a flow of electrons but the electrons do not move at the speed of light. In fact, electrons flow incredibly slowly, at centimetres per hour, making even snails seem like sprinters in comparison.

What does travel fast is the energy in an electric circuit, not the electrons.

The energy travels very fast, almost instantaneously, to all parts of an electric circuit when the circuit is complete, or switched on. However, while the electrons in metals move very slowly, they are never still. Even if there is no electric current, the electrons are constantly moving, though it is more a kind of wriggling around rather than a directional flow.

The speed of flow of an electric charge depends on the current, the thickness of the wire and the type of wire. The higher the current, the faster the charge flows and the thinner the wire, the faster the flow. This is obvious if you imagine a wire to be like a river channel. When a wide river moves into a narrow chanel, the water speeds up and the same thing happens with electric charge in a wire.

How do doctors give stroke patients improved control over their behaviour? About one person in four who suffers a stroke or brain injury may suddenly start to laugh or cry uncontrollably without apparent provocation. Now researchers have found a treatment.

Use of nortriptyline, an anti-depressant drug, gives stroke patients improved control over their behaviour. Doctors are not sure why the drug helps to control the problem, but helping patients gain control is important because their inability to control emotions in public often causes patients to avoid social interaction.