Physics: Lesson 1 (Static Electricity)

subatomic particles (think: parts of an atom)

protons - positive charge, inside the nucleus

electrons - negative charge, orbits the nucleus (can move)

neutrons - neutral charge, inside the nucleus

a neutral atom has an equal number of _____ and ______

protons and electrons

an atom that has gained/lost electrons is called an ____

ion

electrons are the only subatomic particle that can _____

move

neutral vs charged objects

• neutral object does not have any charge (protons = electrons)

• charged object has either lost or gained

  • positive objects lost (deficit)

  • negative objects gained (excess)

law of electric charges (OPPOSITES ATTRACT!)

1. objects that are oppositely charged attract each other

2. objects that have like (same) repel each other

methods to create a charge (3)

1. charging by friction

2. charging by contact

3. charging by induction

charging by friction

• RUBBING two different substances can be given an electric charge

• electrons move from one object to the other

  • one loses, other gains

object that ___ electrons becomes positive

loses, has a weak hold on electrons

object that ____ electrons becomes negative

gains, strong hold on electrons

electrostatic series: higher one ____ electrons (becomes ____), lower one ____ electrons (becomes _____)

loses (becomes positive), gains (becomes negative)

charging by contact (conduction)

if a charged object contacts a neutral object, the second object will become the same charge of the object that touched it

now these two object will repel each other

charging by induction

if a charged object is brought close to the object, the electrons will be attracted/repelled depending on the charge of the object

negative object + neutral object

if charged object is negative, electrons (negative) in the neutral object will be repelled away from the area closest to the charged object, creating a positive charge in that area

positive object + neutral object

if the charged object is positive, electrons in the neutral object will be attracted to the charged object, creating a negative charge in that area

electrons are the only ones moving because they are the only subatomic particle that can move

grounding (induction)

• ground connects to the Earth (can gain/lose many electrons and remain neutral)

• when an object is grounded, it becomes neutral

applications of static electricity

• electric discharge

• lightning

• photocopiers

• electrostatic painting