Post on 18-Dec-2015
transcript
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 wavesTransverse: 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.
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 wavesAmplitude: 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’dFrequency: the number of complete waves
that pass a given point in a certain amount of time. Measured in Hertz Hz
Properties of waves Ct’dSpeed: 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 SoundDepends 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 SoundIntensity: 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 SoundFrequency: the number of vibrations that
occur per second. Most people hear 20 Hz to 20,000 HzUltrasound: frequencies above the normal
range of hearing.Infrasound: Sounds with frequencies below
the normal range of hearing.
Properties of SoundPitch: 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.