Unit 3: Electrical Principles Introduction GO D.2A DESCRIBE TECHNOLOGIES FOR TRANSFER AND CONTROL OF ELECTRICAL ENERGY

Unit Focus Questions: How do we obtain and use electrical energy? What scientific principles are involved? What approaches can we use in selecting, developing and using energy-consuming devices that are efficient and effective in their energy use?

Where do Charges come from? all matter is made up of atoms atoms are made up of electrons, protons, and neutrons protons have a positive charge electrons have a negative charge neutrons have no charge in all matter there are positive and negative charges

Structure of the Atom Electron (-) Nucleus: protons (+) & neutrons

Types of Charges when an object has a negative charge it has extra electrons when an object has a positive charge it has a deficit of electrons a neutral charge is the result of a balance of charge (an equal number of positive and negative charges) during any transfer of charge it is the electrons that move when a charged object touches a neutral object the charged object looses its charge and becomes grounded

Types of Charges e- e-

Law of electrical Charges Challenge How can you use a balloon to make a pop can roll across the room without touching it?

Law of electrical Charges How it Works? You pile up electrons on one thing and use them to attract the protons in something else. When you rub a balloon on your hair, it ends up loaded with electrons. Those electrons can attract the protons in a soda can.

Law of electrical Charges When you rub a balloon on your head you can then stick the balloon onto the wall, why does this happen?

Law of electrical Charges Electrons go from your head to the balloon, the balloon gathers a negative charge. The electrons in the wall move leaving a positive charge on the wall (separation of charge). The (negative) balloon is now attracted to the (positive) wall.

Law of electrical Charges Unlike charges attract. Like charges repel. Charged objects attract uncharged (objects).