2. Electricity—Chapter 7 IPC-- Mrs. Zagala

3. IPC Chapter 7: Electricity Section 1: Electric Charge * Electric Charges ex: rubbing shoes on carpet *All objects have both positive and negative charges (p and e) *Static Electricity-the accumulation of excess electric charges on an object fig. 2 (pg. 95 )

4. Electricity (cont’d.) section 1 Law of Conservation of Charge -charge can be transferred from object to object, but cannot be created or destroyed Law of Conservation of Charge -charge can be transferred from object to object, but cannot be created or destroyed

5. Electricity (section 1 cont’d) Electrically charged objects obey two rules: Electrically charged objects obey two rules: Opposite charges attract Opposite charges attract Like charges repel Like charges repel (similar to two ends of a magnet) (similar to two ends of a magnet) (clothes out of the dryer ex) (clothes out of the dryer ex)

6. Electricity (section 1 cont’d) Force at a Distance: Force at a Distance: An electric field surrounds every electric charge An electric field surrounds every electric charge The electric field exerts the force that causes other electric charges to move The electric field exerts the force that causes other electric charges to move ex: tissue paper sticks to a charged balloon

7. Conductors and Insulators Conductors—materials through which electrons can move more easily Conductors—materials through which electrons can move more easily Ex: skin, metals, etc. Ex: skin, metals, etc. Insulators—a material that doesn’t allow electrons to move through it easily Insulators—a material that doesn’t allow electrons to move through it easily

8. Transferring Electric Charge ( 2 different methods) Charging by contact: Charging by contact: The process of transferring charge by touching or rubbing The process of transferring charge by touching or rubbing Charging by induction: * The rearrangement of electrons on a neutral object caused by a nearby charged object (fig. 7 pg 198)

9. How Lightning Occurs Lightning is a large static discharge Lightning is a large static discharge (a transfer of charge through the air between two objects because of a buildup of static electricity) (a transfer of charge through the air between two objects because of a buildup of static electricity) As air masses move in a thundercloud, areas of positive and negative charge build up As air masses move in a thundercloud, areas of positive and negative charge build up Eventually, a discharge occurs between the cloud and the ground Eventually, a discharge occurs between the cloud and the ground

10. (More on Lightning) As the electric charges move through air, they collide with atoms and molecules As the electric charges move through air, they collide with atoms and molecules These collisions cause atoms and molecules in air to emit light (sparks we see) These collisions cause atoms and molecules in air to emit light (sparks we see)

11. Thunder Thunder is powerful sound waves produced by lightning Thunder is powerful sound waves produced by lightning Heat produced by electrical energy in a lighting bolt cause air to expand rapidly producing sound waves you hear as thunder Heat produced by electrical energy in a lighting bolt cause air to expand rapidly producing sound waves you hear as thunder Pg. 199 Pg. 199

12. Grounding Providing a path for charge to reach earth is called grounding Providing a path for charge to reach earth is called grounding Grounding is important to protect objects on Earth from lightning damage Grounding is important to protect objects on Earth from lightning damage Ex: metal lightning rod, faucets, sinks, pipes, etc. Ex: metal lightning rod, faucets, sinks, pipes, etc.

13. Detecting Electric Charge Electroscope—an instrument used to detect the presence of electric charges Electroscope—an instrument used to detect the presence of electric charges made up of two thin, metal leaves attached to a metal rod w/a knob at the top **Fig. 10/pg. 201