Static Electricity

Static charge or static electricity refers to an electric charge that tends to stay on the surface of an object, rather than flowing away quickly.

Electric Discharge Electric Discharge is the sudden movement of static charge between two objects For example: When you rub your socks across a carpet, electrons from the carpet may move to you. When you touch a metal doorknob the electrons can move from you to the doorknob and you feel a shock

Static Charges Build up as different materials rub together (called charging by friction) Here, one material has a stronger attraction to electrons than the other material, hence, both materials become charged

Examples 1. Hair and comb: Both start out neutral After rubbing, some electrons move from the hair to the comb Hair is now positively charged and comb is negatively charged (hair is attracted to comb) 2. Plastic wrap Containers such as glass and hard plastics have a positive charge on the surface Plastic wrap has an opposite charge which allows it to cling to the container

Charges at Work

Lightning Electrons are carried into the air through the evaporation of water molecules and the production of exhaust gases. When thunderclouds form, large numbers of electrons gather at the bottom of the clouds. Lightning is a huge spark which is created as the electrons move from the clouds to the ground or between two clouds.

http://www.youtube.com/watc h?v=RDDfkKEa2ls Video http://www.youtube.com/watc h?v=RDDfkKEa2ls

Static Cling Film Advertisers use static cling vinyl film for brightly coloured removable signs, decals and stickers Windows of many homes, office buildings and cars are covered with filters that screen our sunlight These screens use static electricity to cling to the window

Photocopiers Photocopiers contain selenium. This material is an insulator in the dark but becomes a conductor in bright light. The negatively charged ink called toner is attracted to the positive charges in the image As positively charged paper moves past the drum (belt) the toner particles are transferred to the paper, recreating the image