Conservation of Electric Charge
Two types of electric charge exist – positive and negative. Equal amounts of negative and positive charge cancel each other out leaving neutrality overall. Though charge can be created or destroyed the net amount – positive – negative – equals zero.
Atoms are neutral. They contain equal numbers of positively charged protons and negatively charged electrons. The charge on electrons and protons is equal in magnitude, so overall the atom is neutral.
The Universe as a whole is probably neutral, and so is every large body in it, or very nearly so. The electric force between an electron and proton is about
times larger than the force of gravity, so if any large body is not electrically neutral, the charge on it must be very small or it would disturb the obit of that body.
Though charge can move from place to place, the amount of charge gained by one body equals the amount of charge lost by another. The net amount of charge remains the same. For example when you brush your hair, electrons move between your hair and the brush. The charge lost by the brush will be the charge gained by your hair. It can easily be shown that both are charged. Your hair will be attracted to the brush because for example, your hair is negatively charged and the brush is positively charged. Your hair stand up because the strands, being of like charge, repel each other. If you bring the brush close to a running tap, the water will be attracted to the brush.
