Year 9 Science: Waves - Characteristics, Properties, and Equations

Vocabulary flashcards covering wave fundamentals, types of waves (transverse and longitudinal), wave characteristics (amplitude, wavelength, frequency, period), and key wave calculations.

Wave

A travelling vibration created by a vibrating object that transfers energy from one location to another without transferring matter.

Longitudinal wave

A wave in which the vibrations of the particles are parallel to the direction of travel of the wave (examples include sound waves, seismic P-waves, and shock waves).

Transverse wave

A wave in which the vibrations occur at $90^\natural$ (perpendicular) to the direction of travel of the wave (examples include light, electromagnetic waves, water ripples, and seismic S-waves).

Compression

A region in a longitudinal wave where the vibrating particles or coils are closest together.

Rarefaction

A region in a longitudinal wave where the vibrating particles or coils are spread furthest apart.

Peak (Crest)

The highest point or top of a wave.

Trough

The lowest point or bottom of a wave.

Equilibrium position

The undisturbed central resting line of a wave representing zero displacement.

Amplitude

The height of a wave measured from the equilibrium position (zero displacement) to the peak or crest.

Wavelength ($\lambda$)

The distance over which the wave shape repeats, corresponding to the length of one whole wave (such as from crest to crest or compression to compression), measured in meters ($\text{m}$).

Frequency ($f$)

The number of complete waves produced per second, measured in Hertz ($\text{Hz}$).

Period ($T$)

The time taken to produce one complete wave cycle, measured in seconds ($\text{s}$).

Reciprocal relationship of frequency and period

The mathematical relationship showing that frequency and period are inverses of one another, expressed as $f = \frac{1}{T}$ and $T = \frac{1}{f}$.

The Wave Equation

The formula relating wave speed, frequency, and wavelength: $v = f \times \lambda$, where $v$ is wave speed in $\text{m/s}$, $f$ is frequency in $\text{Hz}$, and $\lambda$ is wavelength in $\text{m}$.

Wave speed

The speed at which a wave travels, calculated as $\text{Speed} = \frac{\text{Distance}}{\text{Time}}$ or $v = f \times \lambda$, expressed in meters per second ($\text{m/s}$).

Seismic P-waves

Primary earthquake waves that are longitudinal in nature and propagate via compressions and rarefactions.

Seismic S-waves

Secondary earthquake waves that are transverse in nature, with vibrations perpendicular to the direction of propagation.