Created by kat1jj almost 6 years ago
atoms are basic particles from which all matter is made up. each atom has a nucleus consisting of protons and neutrons. the nucleus is surrounded by electrons.
static electricity- material that allow electricity to flow through them easily are called electrical conductors.metals are good electrical conductors. plastics and many other materials, on the other hand, do not allow electricity to flow through them; they are called insulators.however it is possible for an insulator to become electrically charged if there is friction between it and another insulator. when this happens, electrons are transferred from one material to the other. the insulator is then charged with static electricity. it is called static because the electricity stays on the material and does not move.you can generate static electricity by rubbing a balloon against your jumper. the electrically charged balloon will then attract very small objects.electric charge(static) build sup when electrons (which have a negative charge) are rubbed off one material to another. the material receiving electrons become negatively charged and the material giving up electrons becomes positively charged. the charges transferred are equal and opposite.for example- if you rub a perspex rod with a cloth, it loses electrons to become positively charged. the cloth gains electrons to become negatively charged.if you rub an ebonite rod with a piece of fur, it gains electrons to become negatively charged. the fur loses electrons to become positively charged.
REPULSION AND ATTRACTION when two charged materials are brought together they exert a force on each other so they are attracted or repelled . two materials with the same type of charge repel each other; two materials with different types of charge attract each other. if you move a charged ebonite rod near to a suspended charged perspex rod, the suspended perspex rod will be attracted.if you move a second charged perspex rod near to the suspended charged perspex rod, the suspended perspex rod will be repelled
common electrostatic phenomenalightning: clouds become charged up by rising hot air until discharge occurs: a bolt of lightning.charges of synthetic fabric: static sparks when synthetic clothing is removed from the body.shocks from car door: a car can become charged up due to friction between itself and air when it moves.
using static in everyday life- laser printer - an image of the page to be copied is projected onto an electrically charged plate ( usually positively charged)-light causes charge to leak away, leaving an electrostatic impression of the page. -this charged impression on the plate attracts tiny specks of oppositely charged black powder, which are then transferred from the plate to the paper. heat is used to fix the final image on the paper.- electrostatic painting- attractive electrostatic force pulls paint onto object. increased coverage- less waste+fastersmoke reduction- smoke particles pick up negative charge. smoke particles are attracted to the collecting plates. collecting plates are knocked down. crop spraying- the spray gets negatively charged. their attracted to each other. it goes all over the crop.
DANGERS OF STATIC ELECTRICITY - LIGHTNING- negative charge builds up in cloudsFRICTION MADE ON YOURSELF NEAR FLAMMABLE LIQUIDS- ignited flammable liquidsREFUELING AEROPLANES- insulator stops static building up. metal wire loops round electricity to stop build up.ELECTRIC SHOP- build up of static electricity
DISCHARGING UNSAFE STATICfilling aircraft fuel tanksduring refuelling, the fuel gains electrons from the fuel pipe, making it the pipe positively charged and the fuel negatively charged. the resulting voltage between the two can cause a spark, which could cause a big explosion. to prevent it: - the fuel tank can be earthed with a copper conductor.- the tanker and the plane can be linked with a copper conductor
EARTHING! earthing allows a constant safe discharge to occur, to equalise the electron imbalance between the two objects. when earthing occurs, electrons flow from one body to the other to remove the imbalance.