Sonar: A technique that uses sound waves to navigate, communicate, or detect objects underwater.

Amplitude (height of the wave): The maximum displacement or distance that a wave moves from its equilibrium position.

Longitudinal: A type of wave motion in which the particles of the medium vibrate parallel to the direction of the wave propagation.

Transverse: A type of wave motion in which the particles of the medium vibrate perpendicular to the direction of the wave propagation.

Electromagnetic spectrum: The range of all possible frequencies of electromagnetic radiation, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Decibels: A unit used to measure the intensity or loudness of sound or the power level of an electrical signal.

Trough: The lowest point or valley of a wave.

Doppler effect: The change in frequency or wavelength of a wave as observed by an observer moving relative to the source of the wave.

Electricity: A form of energy resulting from the movement of charged particles, such as electrons.

Insulator: A material that does not easily allow the flow of electric current.

Conductor: A material that allows the flow of electric current.

Closed circuit: A complete and uninterrupted path for electric current to flow, typically consisting of a power source, conductors, and a load.

Electric current: The flow of electric charge through a conductor, typically measured in amperes.