Making Sense of Static Electricity The law of attraction and repulsion states: Like charges repel and unlike charges attract Benjamin Franklin named charges positive and negative Benjamin Franklin:enjaminfranklin/preview.wemlhttp://www.brainpop.com/science/energy/b enjaminfranklin/preview.weml Conductors Allow the easy flow of electricity loosely bound electrons that are free to move from atom to atom metals like aluminum, gold, copper and silver Insulators Insulators resists the flow of electrons hold more tightly to their valence electrons: plastic, rubber, glass Do Neutral Objects Lack a Charge? When you rub two neutral object together, they both become charged. This means that neutral objects must already have some charges. Neutral objects have the same number of positive and negative charges. The positive charges in one neutral object will attract the negative charges in another object. Although the objects have the same number of positive and negative charges they are rearranged so that the object appears charged. Static Charge Latin word Stasis which means Stays Objects are typically Neutral w/ the same # of protons and electrons They can become charged by gaining or losing electrons NOT PROTONS! They stay in the nucleus! The buildup of these charges is Static Electricity In Static Electricity the charges build up and STAY; they dont flow as they do in electric currents Testing for a Charge A metal leaf electroscope can detect the presence of a charge. An electroscope has one or two light weighted strips of metal that easily bend. These metal leaves are attached to a central metal rod with a metal sphere at the top. How an Electroscope Works When a negatively charged rod touches the sphere of the electroscope, negative charge spreads throughout the metal. Since the leaves are both negatively charges they repel each other. When a positively charged rod touches the sphere, negative charges move towards the sphere causing the leaves to become positively charges. Questions Complete the worksheet Questions 1 5 page 306 in the Text book.