Discharging objects

• Energy is the ability to do work
• Discharged or neutralised


  When extra charges on a charged object are removed, the object becomes neutral
• Electric discharge


  • Lightning
  • Sparks
  • Shock
• Main ways to discharge a charged object

  • Grounding
  • Discharging at a point
  • Humidity
  • Sparks & lightning
• Grounding


  1. When a charged object is connected to the Earth it becomes neutral

  2. If an object is negatively charged and grounded - electrons flow INTO the Earth from the object

  3. If an object is positively charged and grounded - electrons flow FROM the Earth to the object
• Grounding


  • Outlets - Grounding wires in electric circuits and outlets
  • Lightning rods - Lightning normally strikes the highest point in an area during a thunderstorm, lightning rods are metal and are connected to the ground using metal conductors, when lightning strikes a lightning rod, the charges can be carried safely to the ground, preventing the building from catching on fire
  • Gas pump - Static charges can build up when gas moves through a gas pump (friction), gas pumps must be grounded so excess static charges will be removed, if a spark were created it could ignite the gasoline and start a fire
  • Electronics - Electronics are very sensitive to electrical discharge, this strap is worn when working with computers so there is always a path for electrons to get to the ground
• Why should you always touch the side of your car before filling it with gas?
• Discharging at a point

  Pointed conductors lose charges quickly because extra electrons build up at the point and push each other off the conductor as they repel each other
• Discharging at a point


  • Static wicks on airplane wings remove charge build up caused by friction as the plane moves through the air
• Humidity


  A charged object can become discharged by humid air (contains water vapour) because the moisture in the air absorbs excess charge found on objects
• Humidity


  • Hair conditioner, fabric softener, and dryer sheets stop electrons from leaving the surface of hair and clothing by coating the surface of objects with a thin layer of chemicals
• Sparks & lightning


  Every object has a limit to the number of extra charges it can collect, when the object reaches its limit it must be discharged, this is the main cause of both sparks and lightning
• Sparks & lightning


  • When you rub your feet across the carpet, you are charging your body by friction, these built-up charges will jump across the air to anything that is close - especially a metal tap, car door or doorknob
  • Lightning is just a very large spark, during a large storm, clouds can get VERY tall, and are full of water vapour and other gas particles, as the gas particles rise and fall in the cloud, they rub against each other and become charged through friction, eventually, negatively charged particles build up at the bottom of the cloud, when the number of electrons at the bottom of the cloud gets large enough, they discharge to the ground, we see this discharge as lightning
• Discharged or neutralised


  When extra charges on a charged object are removed, the object becomes neutral
• Electric discharge


  • Lightning
  • Sparks
  • Shock
• Main ways to discharge a charged object

  • Grounding
  • Discharging at a point
  • Humidity
  • Sparks & lightning
• Grounding


  1. When a charged object is connected to the Earth it becomes neutral

  2. If an object is negatively charged and grounded - electrons flow INTO the Earth from the object

  3. If an object is positively charged and grounded - electrons flow FROM the Earth to the object
• Grounding


  • Outlets - Grounding wires in electric circuits and outlets
  • Lightning rods - Lightning normally strikes the highest point in an area during a thunderstorm, lightning rods are metal and are connected to the ground using metal conductors, when lightning strikes a lightning rod, the charges can be carried safely to the ground, preventing the building from catching on fire
  • Gas pump - Static charges can build up when gas moves through a gas pump (friction), gas pumps must be grounded so excess static charges will be removed, if a spark were created it could ignite the gasoline and start a fire
  • Electronics - Electronics are very sensitive to electrical discharge, this strap is worn when working with computers so there is always a path for electrons to get to the ground
• Why should you always touch the side of your car before filling it with gas?
• Discharging at a point

  Pointed conductors lose charges quickly because extra electrons build up at the point and push each other off the conductor as they repel each other
• Discharging at a point


  • Static wicks on airplane wings remove charge build up caused by friction as the plane moves through the air
• Humidity


  A charged object can become discharged by humid air (contains water vapour) because the moisture in the air absorbs excess charge found on objects
• Humidity


  • Hair conditioner, fabric softener, and dryer sheets stop electrons from leaving the surface of hair and clothing by coating the surface of objects with a thin layer of chemicals
• Sparks & lightning


  Every object has a limit to the number of extra charges it can collect, when the object reaches its limit it must be discharged, this is the main cause of both sparks and lightning
• Sparks & lightning


  • When you rub your feet across the carpet, you are charging your body by friction, these built-up charges will jump across the air to anything that is close - especially a metal tap, car door or doorknob
  • Lightning is just a very large spark, during a large storm, clouds can get VERY tall, and are full of water vapour and other gas particles, as the gas particles rise and fall in the cloud, they rub against each other and become charged through friction, eventually, negatively charged particles build up at the bottom of the cloud, when the number of electrons at the bottom of the cloud gets large enough, they discharge to the ground, we see this discharge as lightning