Wave: a disturbance that transfers energy from place to place. The material through which a wave travels through is called a medium. Waves that require a medium are called mechanical waves. The waves don’t carry the medium itself with them. Waves are created when a source of energy causes a medium to vibrate.
Types of waves Transverse: move the medium at right angles to the direction in which the waves are traveling. Longitudinal /Compressional: move particles of the medium parallel to the direction in which the waves are traveling. Surface waves: combinations of transverse and longitudinal waves. They occur at the surface between two mediums, such as water and air. Causes water to move in a circle.
Transverse Waves The highest points are called the crest, and the lowest are called the troughs.
Longitudinal / Compressional: The parts where the coils are close together are called compressions. The parts where the coils are spread out are called rarefactions.
Properties of waves Amplitude: the maximum distance the particles of the medium carrying the wave move away from rest position. It is a direct measure of energy.
Properties of waves Ct’d Wavelength: distance between two corresponding parts of a wave.
Properties of waves Ct’d Frequency: the number of complete waves that pass a given point in a certain amount of time. Measured in Hertz Hz
Properties of waves Ct’d Speed: Waves in different mediums travel at different speeds. In addition the speed is related to the amount of pressure and temperature.
Sound Sound waves carry energy through a medium without the particles of the medium traveling along. A common medium is air. It travels as a longitudinal wave. Sound waves can bend around a barrier, diffraction such as hearing around a corner.
Speed of Sound Depends on elasticity, density, and temperature. Elasticity: Travels more quickly in things that have more elasticity. The speed is faster in a solid, then liquid then gas. Density: faster in the LEAST dense items. Temperature: faster in higher temperatures.
Properties of Sound Intensity: the amount of energy the wave carries per second through a unit area. Measured in W/m² Loudness: what you actually hear. Measured in dB decibels. Each 10 dB increase represents a tenfold increase in intensity.
Properties of Sound Frequency: the number of vibrations that occur per second. Most people hear 20 Hz to 20,000 Hz Ultrasound: frequencies above the normal range of hearing. Infrasound: Sounds with frequencies below the normal range of hearing.
Properties of Sound Pitch: description of a sound of how high or low the sound seems to a person. It depends on the frequency. High frequency sound waves have a high pitch while low pitch is made from a low frequency.