Static electricityThe lesson in this video is not to put on a sweater when filling you car with gas. Electricity Electricity is the interaction of electric charges. An electric charge is a physical property of protons and electrons, particles that make up every atom. Static Electricity The buildup of electric charges on an object is called static electricity. One way static electricity is created is through rubbing. Example If you rub a balloon against your head (both of which start neutral), electrons from the atoms that make up your hair get transferred to the balloon. Your hair becomes positively charged due to the loss of electrons. The balloon becomes negatively charged due to the gain of electrons. Example Contd If you then hold the balloon several centimeters from your head, your hair will stand on end. Your hair and the balloon are attracted to each other because opposite charges attract. Portable telephone (cellular telephone) SHELL Gas noticed three incidents during which portable telephones caused the gasoline ignition to service stations. In the first case, the telephone was placed in the trunk of the car while the driver filled the tank; the telephone rang and the fire which followed destroyed the car and the distributor of gasoline. Portable telephone In the second case, a person answered a call while filling the tank and his face was was seriously burned when the gasoline fumes ignited. In the third case, a person was seriously burned when the gasoline fumes ignited; the telephone, which was in the pocket of the person,rang while he/she was filling the tank. Portable telephone The static electricity is the origin of fires at service stations. In fact the gasoline fumes start fires when they become in contact with the static electricity. You never should use the cellular telephone when you fill up the tank. Attention You must IMPERATIVELY turn off your vehicle while you fill the tank, you ensure, while leaving, to close the door and to TOUCH a METAL PART OF the CAR before withdrawing the distributor with gasoline. In this way, your body will not contain any more static electricity at the time you touch the nozzle. Making sense of Static Electricity You walk on the carpet in your bedroom and touch the metal doorknob. You receive a shock (electric discharge). Discuss this situation with a classmate. Give all the explanations necessary. Answer Answer contd When you shuffle your feet across a carpet the friction causes a static charge to build up inside of you. You can suddenly discharge this static electricity when you touch the door knob, therefore you feel the shock due to the flow of electrons. Activity Team of 2 Read pages 307 and 308. Answer the following questions: What makes up matter? Where is the positive charge of the atom found? Where is the negative charge of the atom found? How do the electrons move from an object to another object? What is the charge of an object which loses electrons? What is the charge of an object which gains electrons? Define conductor, insulator and in-between (semi- conductor)and give examples.