Electricity has become the most important source of energy in the world, yet no one has ever seen an electrical charge, and until this century, it was impossible to isolate and study individual charges of electricity. Electricity is a natural phenomenon that comes about because of the negatively and positively charged particles of matter. These particles are tiny parts of atoms, called protons and electrons. When a substance is in its normal state, the charges on these particles are more or less in balance. The natural arrangement of protons and electrons in a substance is a disorganized one. However, when something changes the material -- something as simple as vibration, friction, heat, or being close to another substance –