Презентация по физике на тему Charge and Charge Interactions: Conductors and Insulators

Charge and Charge Interactions: Conductors and Insulators Key words: electrons, conductors, insulators, charge By the end of this lesson you will be able to: -Electrical current is produced by the flow of electrons - Compare atomic properties of conductors and insulators What is electricity? Electricity is the flow or negative charge Two kinds of charges After being rubbed, a plastic ruler can attract paper scraps. Ruler carries electric charge Where do charges come from? An atom is a fundamental unit of mattermade up of protons (with a positive charge)neutrons (neutral – no charge)electrons (with a negative charge) + + + – – – What is electricity? Everything is made of atoms which contain POSITIVE particles called PROTONS and NEGATIVE particles called ELECTRONS. Proton (+) Neutron Electron (-) Electrical Charge Electric charge is given the symbol QElectrons are the charge carriersthat flow in an electrical circuit –from the negative to positiveterminals. Electrical Charge Charge is measured in Coulombs which is given the symbol C Electrical Charge The charge on a proton is 1.6 x 10-19C which is the same size as the charge on an electron. What is electricity? Electrons have a negative charge (Q) measured in coulombs (C). Electrons move round a circuit from negative to positive (remember like charges repel, opposites attract) giving rise to an electric current. When a balloon rubs a piece of wool... – electrons are pulled from the wool to the balloon. + + + + + – – – – – wool The balloon: – charged, The wool: +charged Where do charges come from? Law of Electric Charges The law of electric charges states that like charges repel, and opposite charges attract. What is an insulator? Name some conductors and insulators What makes them effective conductors / insulators? What is a conductor? Conductors and Insulators An electrical conductor is a material in which charges can move easily. Most metals are good conductors because some of their electrons are free to move. Conductors are used to make wires. For example, a lamp cord has metal wire and metal prongs. Copper, aluminum, and mercury are good conductors. Conductors and Insulators An electrical insulator is a material in which charges cannot move easily. Insulators do not conduct charges very well because their electrons cannot flow freely. The electrons are tightly held in the atoms of the insulator. The insulating material in a lamp cord stops charges from leaving the wire and protects you from electric shock. Plastic, rubber, glass, wood, and air are good insulators. Exercsise 2 Homework Goodbye!