Waves and Sound

What is a Wave?

A wave is a disturbance that travels through space and matter/through a medium, transferring energy from one point to another without permanently displacing the medium through which it moves.

Wavelength

The distance between successive crests or troughs of a wave(Length of single wave pulse), often measured in meters.

Frequency

How many waves per second. Mesured in Hertz(Hz)

Closed end reflection

Particle momentum is downward at the reflection point causing the reflection to be on the opposite side

Open end reflection

At the reflection point, the particle’s momentum is directed upward, causing the wave to reflect and return on the same side of the medium.

Superposition

When two or more waves meet in the same place, their heights add together temporarily as they overlap, which can lead to wave interference.

Constructive Interference

occurs when two or more waves combine to create a wave with a larger amplitude.

Destructive interference

Occurs when two or more waves combine to create a wave with a smaller amplitude.

Standing Waves

are produced when waves of the same frequency and amplitude traveling in opposite directions interfere with each other, creating fixed nodes and antinodes.

Oscillating Motion

is the back-and-forth movement of an object around a central point in a regular pattern. Examples include the swinging of a pendulum and vibrating strings

What causes sound?

Sound is caused by vibrating objects that create pressure waves in a medium, such as air, which are then detected by our ears.

Sound reflection

is the bouncing back of sound waves when they hit a surface, allowing us to hear echoes.

Sound interference

When two areas of high amplitude (high pressure) overlap, their amplitudes combine or are superimposed, resulting in a louder sound. They can also do this to cancel it out

What happens when a sound source moves relative to an observer?

When a sound source is stationary, sound waves spread out in circular patterns. If the source moves, these circles shift with it. This causes some waves to get compressed (shorter wavelengths) and others to stretch out (longer wavelengths).

Doppler Effect

The shift in a wave’s frequency depending on the observer’s position or motion

Crest

Highest point of the wave

The amplitude of a wave

maximum disturbance from its equilibrium (undisturbed) position

longitudinal waves

In longitudinal waves, like sound waves, the displacement of the medium is parallel to the direction the wave travels. In these waves, the trough corresponds to a rarefaction (a region of reduced pressure or density).

Transverse waves

When a moving wave consists of oscillations occurring perpendicularly to the direction of energy transfer

Elevation

The elevation of a wave is the vertical distance between the crest (peak) and the trough (lowest point) of a wave.