science test

static electricity

the buildup of unbalanced charges on the surface of an object

static electricity is ____ energy. It ______, but does not ____.

potential, builds up, flow

static discharge occurs when-

there is a release of static electricity

the spark you feel is caused by

static discharge

electric current

the flow of electrons from one place to another

electric current is measured in

Amps (I)

voltage

the measure of energy given to the charge flowing in a circuit

voltage is the ____ that drives the charge through the _____

pressure, current

conductors

materials through which electrons flow easily

insulators

materials through which electron cannot flow easily

semi-conductors

materials that can be made to act as conductors

resistance

the opposition to the flow of an electric current

resistance produces _____.

heat

the ____ the resistance, the ____ the current

greater, weaker

resistance is measured in

ohms Ω

resistance is affected by:

1. material - aluminum & copper

2. wire diameter - thicker = lower resistance

3. wire length - shorter = lower resistance

4. temperature - colder = lower resistance

circuit

a complete closed path through which electric currents flow (wires)

electric currents flow in a ____

circle or circuit

parallel circuit

• branches joined to components

• 1 turned off, rest stay on

series circuit

• branches all connected

• 1 turns off, all turn off

components of an electrical system:

1. fuse - protects your house by short-circuiting

2. diode - device that allows electrical current

3. transistor - semi-conductor used to amplify signal

electromagnet

magnet made from a wire bearing a current wrapped around an iron or steel center

electromagnets are _____ magnets and can be _____ off or on

powerful, turned

Make an electromagnet stronger by:

• putting more loops in coil

• making larger core

• increasing current moving through the wire

generator

machine that converts mechanical energy to electrical energy

generators use -

electromagnetic induction to create current

motor

machine that converts electrical energy into mechanical energy