Y9 Physics - Longitudinal waves

Longitudinal wave (A wave in which …transfer)

A wave in which the oscillations are parallel to the direction of energy transfer

Oscillation (A repeated…rest position)

A repeated back-and-forth movement of particles about a rest position

Compression (A region…where particles are…)

A region of a longitudinal wave where particles are close together

Rarefaction (A region…where particles are…)

A region of a longitudinal wave where particles are spread further apart

Wavelength (Thé distance between the…or between’

The distance between the centre of one compression and the centre of the next compression, or between rarefactions

Displacement

The distance a certain point/particle in a wave has moved from its rest position

Amplitude (longitudinal wave) (Thé…position

The maximum displacement of a particle from its rest position

Energy transfer

Longitudinal waves transfer energy without transferring matter

Examples of longitudinal waves

Sound waves, ultrasound waves, and seismic P-waves

Medium

The substance through which a wave travels

Oscilloscope (A device…electrical signals…patterns)

A device that displays electrical signals and shows longitudinal sound waves as transverse wave patterns

Sound and oscilloscopes (Sound…microphone…electrical signal

Sound waves cause a microphone to move forwards and backwards, creating an electrical signal

Positive p.d. (Produced…one direction…sound wave)

Produced when the microphone moves in one direction due to a sound wave

Negative p.d. (Produced…opposite…sound wave)

Produced when the microphone moves in the opposite direction due to a sound wave

Oscilloscope vertical movement (Thé dot…potentialcures difference)

The dot moves up and down due to changes in potential difference

Time-base (A control…across the screen…speed)

A control that makes the dot move across the screen at a steady speed

Time-base off (Thé dot only…

The dot only moves up and down

Time-base on (Thé dot…horizontally…constant speed)

The dot moves across the screen horizontally at a constant speed

Changing the time-base (Changes…time axis…oscilloscope display)

Changes the scale of the time axis on the oscilloscope display

Model (longitudinal wave) (A simplified…wave behaves)

A simplified representation used to explain how a longitudinal wave behaves

Good feature of a wave model

Shows compressions and rarefactions clearly

Limitation of a wave model Particles…perfectly…realistic)

Particles are shown perfectly in line, which is not fully realistic