static electricity

• All matter consists of atoms
• Subatomic particles in atoms

  • Protons
  • Neutrons
  • Electrons
• Protons


  Subatomic particle with a positive charge and a relative mass of 1
• Neutrons


  Uncharged subatomic particle, with a mass of 1 relative to a proton
• Electrons


  Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons
• Protons are positively charged. Electrons are negatively charged
• Charge


  Property of matter that causes a force when near another charge. Charge comes in two forms, positive and negative
• Non-contact forces


  Forces exerted between two objects, even when they are not touching, such as the force of gravity
• Static electricity


  Electric charge that accumulates on an insulated object, for example because of friction
• Generally, the atom has a neutral charge, but if it loses an electron, it becomes positively charged and if the atom gains an electron, it becomes negatively charged
• Electrical charges


  Property of matter that causes a force when near another charge. Charge comes in two forms, positive and negative.
• Ions


  Charged atoms
• Electrons


  Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons.
• Friction


  A force that opposes or prevents movement and converts kinetic energy into heat.
• Insulator


  Material that does not allow charge or heat to pass through it easily.
• Static


  A lack of movement. It means inactivity or stillness.
• Conductor


  A material which allows charge to move easily through it.
• Non-contact force


  Force exerted between two objects, even when they are not touching, such as the force of gravity.
• Attraction


  When two or more things come together, eg the north pole of a magnet is attracted to the south pole of a magnet.
• Repulsion


  When two or more things are forced apart, eg the north pole of a magnet is repelled by the north pole of another magnet.
• Repel


  Objects that tend to push apart because of a force between them repel each other.
• Attract


  Objects that tend to move together because of a force between them attract each other.
• Acetate


  A type of transparent plastic film.
• Charging by friction


  1. Electrons gain energy from friction

  2. Electrons rub off onto one material

  3. Material that gains electrons becomes negatively charged

  4. Material that loses electrons becomes positively charged
• Opposite charges


  Attract
• Like charges


  Repel
• Charged objects


  • Charged rod can pick up small pieces of paper
  • Charged balloon can stick to the wall by attraction
  • Charged rod can pull a stream of water towards it
• The forces of attraction or repulsion are greater when the charged objects are closer
• Electric field


  Area surrounding an electric charge that may influence other charged particles
• Electric field


  • Field lines point away from positive charges and towards negative charges
  • With a radial field around a positive charge, other positive charges are repelled away
  • If a negative charge is placed in that field, it would attract the positive charge and feel a force in the opposite direction to the field lines
  • The field between two parallel plates, one positive and the other negative, would be a uniform field
• Radial field


  When field lines spread out from a single point. Eg an electron on its own will have a radial field.
• Uniform field


  When field lines are neat and ordered, usually from one charged plate to another.
• If the field is strong enough, charges can be forced though insulators such as air and a spark will occur. This is what happens during a lightning strike.
• A person dragging their feet across the carpet may become charged, so if they reach out to touch a door handle there is a spark and they feel a small shock.
• Van de Graaff generator

  • A machine that causes friction between a rubber belt and plastic rollers in order to build up electrical charge on a metal dome
  • Removes electrons to produce a positive charge
  • A person does not have to touch the Van de Graaff generator to start feeling the effects, as static electricity is a non-contact force
  • A person touching the dome of the Van de Graaff generator will also lose electrons and become positively charged
  • The same will happen to each of their hairs, causing them to stick out from the head in all directions
• The motion of charged particles causes electrical effects, small shocks, lightning and sparks.
• Electrical fields cause forces to act on charged particles.