Waves

Página 1

Waves

Parts of a Wave

Peak- Highest point above the rest position

Trough- Lowest point below the rest position

Rest Position- The undisturbed position of particles or fields when they are not vibrating

Amplitude- The maximum displacement of a point of a wave from its rest position

Wavelength- Distance covered by a full cycle of the wave

Period- The time taken for a full cycle of the wave

Frequency- The number of waves passing a certain point each second

Displacement- The distance that a certain point in the medium has moved from its rest position

Medium- A material through a wave can be transmitted

Longitudinal Waves

The vibrations are parallel to the direction of travel

Longitudinal waves show areas of compression and rarefaction

Compression- Regions of pressure due to particles being close together

Rarefaction- Regions of low pressure due to particles being spread further apart

Transverse Waves

The vibrations are perpendicular to the direction of travel

Wave Period and Wave Speed Calculations

Wave Speed (v) = frequency multiplied by wavelength

Period (T) = one divided by the frequency

Production of sound

Sound is produced by a vibrating object

Waves transfer energy not matter

The wave travels parallel to the direction of travel (longitudinal wave)

High Frequency = High Pitch

Big Amplitude = louder sound

Transmission of Sound

Once one molecule vibrates, it hits another and that molecule vibrates causing a chain reaction. This is how sound transfers.

Practicals:

Apparatus - form pad, alarm, vacuum, pump.

Put the alarm (turned on) into the vacuum on top of the foam psd. Using the pump take air molecules out of the vacuum. This will make the alarm much quieter because there will be less air molecules to hit and transfer through.

Sound can travel through both solids and liquids.

Cathode Ray Oscilloscopes

The C.R.O is an electron gun. It moves across a fluorescent screen from left to right at a certain speed. The electron gun shoots electrons and down according to the electric signal. It was used in old analogue televisions. The electrons would hit the fluorescent screen and with the light, form a picture.