What is an electric field and how does it affect us?

What is an electric field and how does it affect us? — MT, Brampton, Ontario

Electrically charged particles exert forces on one another. For example, a negatively charged particle attracts a nearby positively charged particle and repels another negatively charged one. These attractions and repulsions are mediated by electric fields that are created by those charges. By this statement, I mean that the negatively charged particle creates an electric field around itself and this electric field is what ultimately exerts forces on the other two charges—attracting the nearby positively charged particle and repelling the negatively charged one. Whenever an electrically charged particle finds itself in an electric field, it experiences a force. The direction of that force depends on its electric charge (either positive or negative) and on the direction of the electric field (which may have somewhat different directions at different points in space). The strength of that force depends on the amount of electric charge on the particle and on the strength of the electric field (which can vary from nothing at all to extremely strong).

But while electric fields always exist around charged objects and exert forces on any other charged objects that enter them, electric fields can also exist far away from charges. Electromagnetic waves contain electric and magnetic fields (the magnetic equivalents of electric fields) and these two fields sustain one another as the wave travels. Although electromagnetic waves are created and destroyed with the help of charged particles, they can travel alone and without any nearby charged particles to assist them.

While electric fields exert forces on the charged particles in our bodies, the response of those charges isn’t likely to injure us. When you are exposed to an electric field, there is a subtle rearrangement of electric charges on the surface of your body that then creates its own electric field. The result is that there is essentially no electric field inside you. Only when you are exposed to extremely strong electric fields, and spark and currents begin to flow through you, is there any significant effect to you.

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