Static electricity

• static electricity important frase is friction transfers electrons
• it is possible to transfer electrons from one material to another by rubbing them together, this is called charging by friction.
• opposite charges attract
• same charges repel
• electrons are the easiest particle to remove from an attom
• when an electron is removed from an atom it becomes positively charged (cation)
• when an atom gains an electron it becomes negatively charged (anion)
• positive and negative charge are pulled together by the electrostatic force of attraction
• two positive or negative charge are pushed apart by the electrostatic force of repulsion
• von graaff generator dome gains energy by electrons being removed
• hair stands up when being charged by balloon as all strands of hair have same charge so repel
• work done = charge x voltage
• potential difference = work done per unit charge
• the more charges there are, the greater the potential difference between them
• a balloon is rubbed against jumper then sticks to wall. this is because the balloon has opposite charge to wall so they are attracted to each other.
• you can discharge a charged object by giving it a way to drain its electrons to the ground
• when two objects with different charges touch, their charges mix together until both objects have equal but opposite charges e.g. conductive rod drains electrons from von graaff generator to the ground
• if you charge an object that is a conductor, the charge will flow of it again to ground.
• for an object to stay charge you either:

  charge an insulator (so charge cant flow) OR insulate a conductor from the ground (so charge cant flow to ground)