What are waves?

MT 6 LT 1

Background Knowledge: Waves

What are some examples of waves?

Why are waves important?

What causes waves?Waves are created when a source of Energy causes a medium to vibrate.

WAVES NEED ENERGY TO MOVE

A vibration is a repeated back and forth or up and down motion.

What are the different types of Wave?

Mechanical WavesSound WavesElectromagnetic Waves

This LT will focus on Mechanical Waves

What are mechanical waves?

Definition: A disturbance that transfers energy from place to place.

They need a source of energy to produce it

How are waves & energy related?

A wave transports energy along a Medium without transporting matter.

Mediums & WavesWhat do mechanical waves move through?

A mediumMechanical waves require a medium in order to travel from one place to anotherCan be gas, liquid, or solid.

Waves in different mediums travel at different speeds.

Mediums & WavesWhat do mechanical waves move through?

Mechanical Waves do NOT move the medium from one place to another

Note that Not all waves require a medium to travel.

Example: Light from the sun travels through empty space.

What determines the speed of a Mechanical

Wave?

The speed of a wave is determined by its:

Wavelength x Frequency

What are the different types of Mechanical

Waves?

What are the different types of Mechanical

Waves?Waves are classified according to how they move.3 types of Waves:

Transverse WaveLongitudinal WaveSurface Wave

What is a Transverse Wave?

A wave that travels in the opposite direction (perpendicular) to the medium in which it is traveling through

Transverse means across.

Basic Properties of Transverse Waves (What are the parts of

a Transverse Wave?)

CrestTroughAmplitude

EnergyWavelength

Basic Properties of Transverse Waves (What are the parts of

a Transverse Wave?)

CrestThe highest point of the wave above the rest position

TroughThe lowest point below the rest position

Transverse Wave: Amplitude

Amplitude is the distance from the rest to crest or rest to trough.

The farther a medium moves as it vibrates, the larger the amplitude.

Rest

Transverse Wave: Amplitude

The Amplitude tells us the amount of energy being transported.

High Energy = High AmplitudeLow Energy = Low Amplitude.

Transverse: WavelengthA wave travels a certain distance before it repeats. When it repeats, it is knows as the WavelengthThe wavelength is the distance between 2 corresponding (same/related) parts of a wave .

Measured from crest to crest or trough to trough.

Wave HeightThe distance from one crest to one trough (trough to crest too)

Draw a Transverse Wave and label: crest & trough

Properties of Longitudinal/Compression

al Waves

Longitudinal WaveThe vibration of the medium is the same direction (parallel) to the direction in which the wave travels.

Example: Slinky

Longitudinal WaveCompressions:

The parts where the coils are close together

Rarefactionsthe parts where the coils are spread out

What is a Surface Wave?

Surface WavesA wave that travels along a surface separating two media