Physics P5 Waves

Wave

An oscillation that transfers energy

Longitudinal wave

Is when the direction of vibration of air particles are parallel or the same direction as direction of wave travel. It has compressions and rare fractions which show when the air particles collide and transfer the energy in direction of wave travel

Transverse wave

Is a wave where the vibration of air particles are perpendicular to the direction of travel. Transverse waves have troughs and crests and a wavelength is measured from any point on the wave to the same point on the other wave.

Amplitude

Amplitude is measured by the distance from the middle of the wave to the crest or the trough. The amplitude shows how loud or quiet. The higher the amplitude the louder the sound and the more energy the wave transfers. Amplitude is the maximum displacement of the wave

Wavelength

Distance from one point on the wave to the same point on the next wave. Wavelength will stay the same for all mediums as wavelengths determine the characteristics of the wave e.g INFARED of gamma rays. Measure in meters

Frequency

The number of oscillations per second. The frequency determines the pitch of the wave for sound waves. The higher the frequency the higher the pitch and the more energy transferred in the wave measure in Hz

Time period

The time it takes for a wave to reach a certain point or pass a given point. Measured I’m seconds

Wave velocity

How fast a wave travels e.g sound wave has a wave velocity of 330m/s in air. This can be calculated from wave velocity = frequency * wavelength

Refraction

When a wave changes direction when it enters a different medium or area which changes the speed of the wave. TAG AGA. The normal is 90^ to the surface, just place a ruler and draw straight

Ultrasound

Ultrasound is sound with a frequency greater that 20KHz. Our natural hearing ability is only up till 20KHz but animals like dogs can hear.

Echo sounding

Where the distance is calculated when sound is sent out as a pulse to different objects e.g the sea bed from ship. When objects are hit the sound is reflected and the receiver then receives the echo and the time it takes can be calculated to find the distance

Natural frequency

Natural frequency is when an object vibrates to a frequency of its own depending on the objects characteristics

Resonance

When vibrations are applied to objects with their natural frequency

Spectrum

A merge of light with no gaps between e.g white light spectrum is a rainbow

Electromagnetic spectrum

Is a wider spectrum where there are different waves with different bands of frequencies. Our eyes have a narrow range of frequencies with seeing visible light. The lowest frequency but the highest wavelength is radio waves and the highest frequency but the shortest wavelength is gamma rays. Wavelength and frequency have an inversely proportional relationship

Source

Is something that emits electromagnetic waves e.g sun emits UV

Absorbers

Is something that absorbs electromagnetic waves e.g food in microwave. E-waves transfer energy from sources to absorbers.