2.1 THE BASICS OF ELECTRICITY WHAT IS ELECTRICITY? Where is electricity? Electricity is all around us: it operates technology such as our mobile phones, lights, , and . It’s certainly something we cannot do without because it is always at work, whether in nature (the in a , for example), or inside our body: electricity is what allows our nervous system to send signals throughout the body and the brain and which makes it possible for us to move, think and feel. This phenomenon concerns, therefore, all matter in the universe. soldering irons drills lightning thunderstorm What is an atom? Matter is the name science gives to everything that surrounds us. It consists of molecules that are made up of a combination of atoms. Until the recent past, the atom was regarded as the smallest thing in the universe and it was thought that it could not be divided ; now we know that it consists of , , and even smaller called quarks . Protons, carrying a positive charge, and neutrons, which have no charge, in the – the centre of the atom; electrons, carrying a negative charge, around the nucleus, attracted by the positive charge of the protons. An atom is electrically neutral if it contains the same number of and electrons; otherwise, it is electrically charged and it is known as an . 1 electrons 2 protons neutrons particles 3 are bound nucleus revolve protons ion MORE The name derives from the Greek word for . In 1911, the physicist Ernest Rutherford described the nuclear structure of the atom. 1 atom indivisible The name comes from the Greek for ‘amber’. 2 electron The name comes from the combination of the words qu[estion] + [m]ark. 3 quark Definition Electrons on the outside of the atom can become free from the attractive power of the protons when some kind of energy is to them. When this happens, they can move from one atom to another. This flow of electrons has an electric charge and is called . When electrons are at in one place, the electricity is said to be ; when they are in motion it is (or electric current). Electric current is what we need every day for all of our technological devices. provided electricity rest static dynamic