electricity unit grade 9 science chapter 10 glossary terms
a form of energy that results from the interaction of charged particles, such as electrons or protons.
electric charge that remains "static" or doesnt move.
charging by friction
involves the transfer of electric charge by rubbing or friction
(eg. walking across carpet, combing your hair)
Electrostatics; the study of electric charge
Electrostatic series; used to determine the kind of electric charge produced on each substance when two substances are rubbed together.
a material in which electrons cannot move easily from one atom to another
eg. glass, wool, foam, ebonite
a material in which electrons can move easily between atoms
a material in which electrons can move fairly well between atoms
eg. some non-metals (silicon)
an object that can supply a verry large number of electrons to, or can remove a very large number of electrons from a charged object, thus neutralizing the object
a device for detecting the presence of an electric charge.
eg. pith ball electroscope, metal leaf electroscope
charging by contact
generating a charge on a neutral object by touching it with a charged object.
an object that becomes charged by contact always gets the same type of charge that is on the object that charges it.
laws of electric charges
laws that describe how two objects interact electrically
1. like charges repel eg. (-) + (-) OR (+) + (+) REPEL2.opposite charges attract eg. (-) + (+)3.charged and neutral objects attract :(N)+(-) OR (N)+(+)
A property of the space around a charged object, where the effect of its charg can be felt by other objects
an electric field produces an electric force on any other objects that are in the field.
objects with greater net charges have stronger electric fields
the greater the distance from a charged object, the weaker the electric field of the object is.
induced charge separation
induced charge separation is the movement of electrons in a substance, caused by the electric field of a nearby charged object, without direct contact between the substance and the object.
eg. negative rod near a neutral pith ball causes electrons in the pith ball to move as far away from the rod as the object allows. thus, the electrons in the rod are attracted to the protons in the pith ball.
An ion is a positively or negatively charged atom(s) or molecule(s)
A lightning rod is a metal sphere or point, attached to the highest part of a building and connected to the ground
especially important in ural areas where a house or barn may be the tallest building.
eg. the CN tower has a large lightening rod on top, because it is the tallest structure in the area
makes use of the laws of electric charges
consists of a series of plates and highly charged wires, and can reduce air pollution from dust particles and liquid droplets.
Van de Graaff generator
A device that accumulates very large charges
transferres very large charges
have been used in atom smashers since 1930
a small device that measures exposure to radiation.