electrical current that flows in one direction and then in the opposite direction, back and forth
alternating current
electrical current that flows in just one direction
direct current
any object that attracts certain metal objects
magnet
the part of a magnet where the ability to push or pull is the strongest
pole
the area around a magnet where it can push or pull another magnet
magnetic field
a tool that shows directions by letting a needle line up with Earth's magnetic field
compass
a magnet that is made when an electric current flows through a coiled wire around an iron rod
electromagnet
a tool that changes electrical energy into sound
loudspeaker
a tool that changes sound into electric signals
microphone
a tool that changes electrical energy into energy of motion
motor
a tool that changes energy of motion into electrical energy
generator