static electricity

what happens when certain insulating materials are rubbed together?

negatively charged electrons are scraped off one and dumped on the other leaving the materials electrically charged, one with a positive static charge and the other with an equal negative static charge

what are electrostatic charges produced by?

the movement of electrons

what happens when an electric charge builds up on an object?

the pd between the object and the earth increases

what happens when the pd between an object and the earth becomes large enough?

electrons can jump across the gap between the object and the earth- this is called a spark

what else can electrons jump to?

to any earthed conductor that is nearby

what is attraction and repulsion with electric charges?

2 things with same electric charges repel

2 things with opposite electric charges attract

what happens when the 2 objects get further apart?

the force between them decreases

what type of forces are electrostatic attraction and repulsion?

non contact forces

what is an electric field?

a region around a charged particle or object within which a force would be exerted on other charged particles or objects.

where do electric field lines go from?

positive to negative

where do field lines always act?

perpendicular to surface

what is the force exerted in electric fields caused by?

interaction of the electrical fields of the objects

how are sparks made with electrical fields?

- a high pd creates a strong electric field between charged object and earthed object|

- the strong field causes electrons in the air particles to be removed

- air is normally an insulator, but once it is ionised, it is much more conductive so current can flow through it, causing a spark