1. Unit 13.1 Electrostatics is the study of non-moving electric charges, sometimes called static electricity.

2. Unit 13.2 To understand electrostatics it is first important to understand the basic structure of an atom. An atom is made up of 3 different sub-atomic particles. This is demonstrated in the following diagram showing an atom of beryllium. - - - - + + + + electron nucleus proton neutron

3. Unit 13.2 - + electron nucleus proton neutron + + + - - - A proton is a positively-charged sub-atomic particle that is found in the nucleus. A neutron is a sub-atomic particle that carries no charge & also found in the nucleus. An electron is a negatively-charged sub-atomic particle that orbits around the nucleus. + -

4. Unit 13.2 - - - - + + + + electron nucleus proton neutron How many electrons are there present in the beryllium atom? 4 electrons.

5. Unit 13.2 - - - - + + + + electron nucleus proton neutron How many protons are there present in the beryllium atom? 4 protons.

6. Unit 13.2 - - - - + + + + electron nucleus proton neutron Beryllium atom is neutral, i.e. it is not charged. This means that the total amount of positive charge cancels out the total amount of negative charge. It means a positive charge is equal in magnitude but opposite in nature to a negative charge.

7. Unit 13.4 Insulators Examples of insulators are wood, plastics, ebonite, glass, fur, silk. The method of charging by friction will only work when two insulators are rubbed against each other (see Unit 13.1). When an insulator is charged by the friction method the charge remains on the surface of the material. This is because the charge cannot move through the insulator.charging by friction

8. Unit 13.4 Conductors In electrical conductors, the outer electrons (also known as valence electrons) are loosely bound. They are relatively free from individual atoms. We say that these electrons are delocalized. When electrons are gained by the conductors, the other electrons will flow automatically so that electron re-distribution in the conductors occur. When electrons are lost by the conductors, the other electrons will also flow automatically so that electron re-distribution in the conductors occur.

9. Unit 13.4 Conductors All metals are conductors of electricity. All conductors can be discharged easily by a method known as earthing (which will be discussed in a later unit).